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Title:
INTERMEDIATES FOR DINUCLEOTIDE AND OLIGONUCLEOTIDE ANALOGUES
Document Type and Number:
WIPO Patent Application WO/1996/008503
Kind Code:
A1
Abstract:
A compound of formula (I) or salts thereof, where Ro is hydrogen or together with R7O denotes a C1-C15 hydrocarbylidenedioxy group, R1 is hydrogen, R1a or a group of formula (II), R1a is R1b or a protecting group Q, R1b is C1-C20 alkyl, C2-C20 alkenyl, C3-C10 cycloalkyl, C6-C15 aryl, C7-C16 aralkyl or a 5- or 6-membered heterocyclic group attached by a carbon atom in the heterocyclic group to the indicated phosphorus atom, R2 is R2a or -OR15 or together with R5 denotes an oxy group -O-, provided that R2 is -OR15 when R1 is a group of formula (II), R2a is a C1-C20 aliphatic group, a C3-C10 cycloaliphatic group, a C6-C15 aromatic group, a C7-C16 araliphatic group, or a 5- or 6-membered heterocyclic group attached by a carbon atom in the heterocyclic group to the indicated phosphorus atom, R3 is R3a or Z, R3a is hydrogen, halogen, hydroxy, R16, -OR16, OCOR16, -OSO2R16, or tri(C1-C15 hydrocarbyl)silyloxy, R4 is hydrogen, halogen or R17, R5 is R5a or Z or together with R2 denotes an oxy group -O-, R5a is hydrogen, halogen, hydroxy, R18, -OR18, -OCOR18, -OSO2R18, or tri(C1-C15 hydrocarbyl)silyloxy, or together with R6 denotes a C1-C15 hydrocarbylidenedioxy group, R6 is halogen, hydroxy, -OR19, -OCOR19, -OSO2R19 or B1, or together with R5 denotes a C1-C15 hydrocarbylidenedioxy group, provided that R6 is not B1 when R1 is a group of formula (II) in which R14 is B2, R7 is hydrogen or R7a, R7a is R20, -COR20, -SO2R20 or tri(C1-C15 hydrocarbyl)silyl, or together with the attached oxygen atom and Ro denotes a C1-C15 hydrocarbylidenedioxy group, R8 is hydrogen, halogen, hydroxy, R21, -OR21, -OCOR21, -OSO2R21 or together with R10 denotes a valence bond, R9 is hydrogen, halogen or R22, R10 is hydrogen, halogen, hydroxy, R23, -OR23, -OCOR23 or -OSO2R23, or together with R8 denotes a valence bond, R11 is hydrogen, halogen or R24, R12 is hydrogen or R12a, or R12O- together with R13 denotes a C1-C15 hydrocarbylidenedioxy group, R12a is R25, -COR25, -SO2R25 or tri(C1-C15 hydrocarbyl)silyl, R13 is R13a or Z, R13a is hydrogen, halogen, hydroxy, R26, -OR26, -OCOR26, -OSO2R26 or tri(C1-C15 hydrocarbyl)silyloxy, or together with R14 denotes a C1-C15 hydrocarbylidenedioxy group, or together with R12O- denotes a C1-C15 hydrocarbylidenedioxy group, R14 is halogen, hydroxy, -OR27, -OCOR27, -OSO2R27 or B2 or together with R13 denotes a C1-C15 hydrocarbylidenedioxy group, provided that R14 is not B2 when R6 is B1, R15 is hydrogen or R15a, R15a is a C1 to C10 aliphatic group, a C3 to C8 cycloaliphatic group, a C6 to C15 aromatic group or a C7 to C16 araliphatic group, R16, R17, R18, R19, R20, R21, R22, R23, R24, R25, R26 and R27 are independently a C1 to C10 aliphatic group, a C3 to C10 cycloaliphatic group, a C6 to C15 aromatic group or a C7 to C30 araliphatic group, B1 and B2 are independently each a monovalent nucleoside base radical, and Z is substituted or unsubstituted C6 to C10 aryloxythiocarbonyloxy.

Inventors:
Baxter
Anthony
David, Taylor
Roger
John, Collingwood
Stephen
Paul
Application Number:
PCT/GB1995/001955
Publication Date:
March 21, 1996
Filing Date:
August 17, 1995
Export Citation:
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Assignee:
CIBA-GEIGY AG BAXTER
Anthony
David, Taylor
Roger
John, Collingwood
Stephen
Paul
International Classes:
A61K31/70; A61K31/7024; A61K31/7042; A61K31/7048; A61K31/7052; A61K31/7064; A61K31/7068; A61K31/7072; A61K31/7076; A61K31/7135; A61P31/12; A61P35/00; A61P43/00; C07D405/04; C07F9/32; C07F19/00; C07H9/04; C07H13/02; C07H13/04; C07H13/06; C07H13/08; C07H19/01; C07H19/04; C07H19/06; C07H19/16; C07H21/00; C07H23/00; (IPC1-7): C07H21/00; A61K31/70; C07H9/04; C07H13/04; C07H13/08; C07H19/04
Domestic Patent References:
WO1991015499A1
WO1992020822A1
Foreign References:
EP0629633A2
EP0614907A1
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Claims:
CLAIMS
1. A compound of formula or salts thereof, where R° is hydrogen or together with R7O denotes a CjC^ hydrocarbylidenedioxy group, R1 is hydrogen, Rlt or a group of formula R1, is R^ or a protecting group Q. R^ is CrC2o alkyl, C2C20 alkenyl, C3C10 cycloalkyl, CgC^ aryl, C C16 aralkyl or a 5or 6 membered heterocyclic group attached by a carbon atom in the heterocyclic group to the indicated phosphorus atom, R2 is R2t or OR15 or together with R5 denotes an oxy group O, provided that R2 is OR13 when R1 is a group of formula II, R2a is a CrC2o aliphatic group, a C3C10 cycloaliphatic group, a C6C15 aromatic group, a C7 16 araliphatic group, or a 5 or 6 membered heterocyclic group attached by a carbon atom in the heterocyclic group to the indicated phosphorus atom, R3 is R3a or Z, R3. is hydrogen, halogen, hydroxy, R16, OR16, OCOR16, OSO2R16, or tri(CrCl5 hydrocarbyl)silyloxy, R4 is hydrogen, halogen or R17, R5 is R5 or Z or together with R2 denotes an oxy group O, R5a is hydrogen, halogen, hydroxy, R18, OR18, OCOR18, OSO;R18, or r Qs hydrocarbyl)silyloxy, or together with R6 denotes a CjC^ hydrocarbylidenedioxy group, R6 is halogen, hydroxy, OR19, OCOR19, OSO2R19 or B1, or together with R5 denotes a C 5 hydrocarbylidenedioxy group, provided that R6 is not B1 when R1 is a group of formula II in which R is B2, R 7 is hydrogen or R7a, is R20, COR20, SO2R20 or tri(Cr5 hydrocarbyl)silyl, or together with the attached oxygen atom and R° denotes a CjC hydrocarbylidenedioxy group, R8 is hydrogen, halogen, hydroxy, R, OR21, OCOR21, OSO2R21 or together with R10 denotes a valence bond, R9 is hydrogen, halogen or R22, R10 is hydrogen, halogen, hydroxy, R 3, OR23, OCOR23 or OSO2R23, or together with R8 denotes a valence bond, R11 is hydrogen, halogen or R2 , R12 is hydrogen or R12a, or R12O together with R13 denotes a CrCls hydrocarbylidenedioxy group, R12a is R25, COR25, SO2R25 or tri(CC15 hydrocarbyl) silyl, RI3 is R13. or Z, R13a is hydrogen, halogen, hydroxy, R26, OR26, OCOR26, OSO2R26 or tri(CrCl5 hydrocarbyl)silyloxy, or together with R14 denotes a hydrocarbylidenedioxy group, or together with R12O denotes a CJCJJ hydrocarbylidenedioxy group, R14 is halogen, hydroxy, OR27, OCOR27, OSO^27 or B2 or together with R13 denotes a CrC15 hydrocarbylidenedioxy group, provided that R14 is not B2 when R6 is B1, R15 is hydrogen or R15a, R I5a is a to C10 aliphatic group, a C3 to C8 cycloaliphatic group, a C6 to C^ aromatic group or a C to Cϊ6 araliphatic group. R16, R17, R18, R19, R20, R21, R22, R23, R24, R25, R26 and R27 are independently a Q to Cjo aliphatic group, a C3 to C10 cycloaliphatic group, a C6 to 5 aromatic group or a C to C30 araliphatic group, B1 and B2 are independently each a monovalent nucleoside base radical, and Z is substituted or unsubstituted C6 to C10 aryloxythiocarbonyloxy.
2. A compound according to claim 1, in which the aliphatic groups are substituted or unsubstituted alkyl or alkenyl groups, the cycloaliphatic groups are substituted or unsubstituted cycloalkyl groups, the aromatic groups are substituted or unsubstituted aryl groups and *_r.e araliphatic groups are substituted or unsubstituted aralkyl groups.
3. A compound according to claim 1 or 2, in which the alkyl groups are Cl to Cg alkyl, the alkenyl groups are C2 to C4 alkenyl, the cycloalkyl groups are C5 to Cg cycloalkyl, the aryl groups Cδ to C10 aryl, the C7 to C16 aralkyl group is C7 to C aralkyl and the C7 to C3 aralkyl groups arc C7 to C2Q aralkyl, any of which are substituted or unsubstituted.
4. A compound according to claim 3, in which the groups are unsubstituted or substituted by halogen, nydroxy, to C4 alkoxy, cyano, nitro, ammo, Cj to C4 aikyiamino, di(CrC4 alkyl) amino, ai(CrC15 hydrocarbyl)silyl, _ri(CrC15 hydrocarbyl)silyloxy or, in the case of R1 as to Cg alkyl, by a phosphonic ester group.
5. A compound according to any of the preceding claims in which R1 is Q, Q is a Cj to C20 hydrocarbyl group, substituted on the carbon atom thereof attached to the indicated phosphorus atom by at least one hydroxy, CJCJQ alkoxy, hydrocarbyl)silyloxy or αri(C1C1f hydrocarbyl)silyloxy group.
6. A compound according to claim 5, in which Q is of formula IΠA where R28 is hydrogen, CrC10 alkyl, C3C8 cycloalkyl, C6C10 aryl or C7Cu aralkyl, R29 and R30 are independently Cr0 alkyl, C2C4 alkenyl, C6C10 aryl or C7C13 aralkyl, R:* : and R32 are independently CrC10 alkyl, or R31 is CrC10 alkyl and R32 is C6Cιo _ιιyl. and R33 is hydrogen, di(CιCι5 hydrocarbyl)silyl or hydrocarbyDsilyl.
7. A compound according to claim 6, in which R28 is hydrogen or CjC4 alkyl and R29 and R30 are each CrC4 alkyl, R31 and R32 are CrC4 alkyl, and R33 is hydrogen or branched C2C,o alkyl di(C C4 alkyl)silyl.
8. A compound according to any of the preceding claims, in which hydrocarbyl)silyl group is present, it is a tri(C C6 alkyl)silyl, C5 alkyldi(C6C8 aryDsilyl, or branched C2Cl0 alkyl di (CrC4 alkyl)silyl.
9. A compound according to any of the preceding claims, in which when a hydrocarbylidenedioxy group is present, it is a group of formula where R34, R35, R36 and R37 are independently hydrogen, C. to C10 alkyl, C3 to C8 cycloalkyl or C6 to Cj0 aryl.
10. A compound according to claim 9, in which R34, R35, R36 and R37 are Cj to C4 alkyl.
11. A compound according to any of the preceding claims, in which R6 or R14 as a monovalent nucleoside base radical is unsubstituted or substituted thyminyl, uracilyl, cytosinyl or adeninyl.
12. A compound according to claim 1, in which: R1 is hydrogen, C Cj alkyl, C6Cl0 aryl, a protecting group Q of formula IH or UI A as defined in claim 6 or 7, or a group of formula II as defined in claim 1, R2 is R2a which is Cj to C4 alkyl, C2 to alkenyl, C5 to C8 cycloalkyl, C6 to C10 aryl, or C7 to C9 aralkyl, or R2 is OR15, where R15 is hydrogen or unsubstituted or substituted C4 alkyl, or R2 together with R5 denotes an oxy group, R3 is hydrogen, halogen, hydroxy, OCOR16 or OSO2R16 where R16 is substituted or unsubstituted to C alkyl or C6 to Cι0 aryl, tri(C1C6 alkyl)silyloxy or CrC4 alkyl or halogen substituted phenyloxythiocarbonyloxy, and R4 is hydrogen or halogen, R5 is hydrogen, hydroxy or OR18, OCOR18 or OSO2R18 where R18 is unsubstituted or substituted Ct to C4 alkyl, unsubstituted or substituted C6 to CI0 aryl, tritC C hydrocarby silyloxy, or together with R2 denotes an oxy group, or together with R6 denotes a hydrocarbylidenedioxy group of formula IV as defined in claim 9 where R34 and R33 are independently to C4 alkyl, R6 is a monovalent nucleoside base radical B1, hydroxy or OCOR19 where R19 is unsubstituted or substituted Cj to C4 alkyl, or together with R5 denotes a hydrocarbylidenedioxy group of formula IV as defined in claim 9, 12 I.t where R34 and R35 are independently C; to C4 aikyl, R7 is hydrogen, substituted or unsubstituted Ct to C4 alkyl, substituted or unsubstituted C7 to C20 aralkyl, COR20 or SO2R20 where R20 is substituted or unsubstituted Ct to C4 alkyl or substituted or .insubstituted C6 to C10 aryl, or (Ct to C6 alkyl) di (C6C8 aryl) silyl, or together with the attached oxygen atom and R° denotes a hydrocarbylidenedioxy group of formula IV as defined in claim 9 where R34 and R35 are independently to C4 alkyl, R8 is hydrogen, halogen, hydroxy, C{ to C4 alkyl, C to C alkoxy, C7 to C9 aralkyloxy, or OCOR21 or OSO2R21 where R21 is Cj to C4 alkyl or C6 to C10 aryl, or together with R10 denotes a valence bond and R9 is hydrogen, halogen or C, to C4 alkyl, R10 is hydrogen, halogen, hydroxy, Cl to C4 alkyl, C! to C4 alkoxy, C to C9 aralkyloxy, or OCOR23 or OSO^R23 where R23 is to C4 alkyl, or C6 to C!0 aryl. or together with R8 denotes a valence bond and R11 is hydrogen, halogen, or Ct to Cd alkyl, R12 is hydrogen, Cj to C4 alkyl, C7 to C9 aralkyl, or COR25 or SO1R25 where R is substituted or unsubstituted Ct to C4 aikyl or substituted or unsubstituted C6 to C10 aryl, R13 is hydrogen, hydroxy or OR26, OCOR26 or OSO^26 where R is substituted or unsubstituted to C4 alkyl, substituted or unsubstituted C7 to C13 aralkyl or substituted or unsubstituted C6 to CJQ aryl, or together with R14 denotes a hydrocarbylidenedioxy group of formula IVA as defined in claim 9 where R36 and R37 are independently Cj to C4 alkyl, and R14 is hydroxy or OCOR27 where R27 is substituted or unsubstituted Cj to C4 alkyl, or together with R13 denotes a hydrocarbylidenedioxy group of formula IVA where R36 and R37 are independently Cj to C4 alkyl.
13. A compound according to claim 12, in which R1 is hydrogen, methyl or methyl substituted by P(O)(OCH2CH3)2, phenyl, a protecting group Q of formula IH or IHA as defined in claim 7 or a group of formula _I as defined in claim 1, R2 is methyl, ethyl, vinyl, allyl, cyclophenryl. cyclohexyl, methylcyclohexyl, phenyl, tolyl, naphthyl, benzyl, hydroxy, methoxy. ethoxy, 2cyanoethoxy, or isobutoxy, or together with R5 denotes an oxy group, R3 is hydrogen, fluorine, chlorine, hydroxy, OCOR16 or OSO2R16 where R16 is methyl, ethyl, phenyl, tolyl or naphthyl, trimethylsilyioxy or ptolyloxythiocarbonyloxy and R4 is hydrogen, R3 is hydrogen, hydroxy or OR18, OCOR18 or OSO2R18 where R18 is methyl, ethyl, phenyl, tolyl or naphthyl, tenbutyldiphenylsilyloxy or thexyldimethylsilyloxy, or together with R denotes an oxy group or together with R6 denotes an isopropylidenedioxy group, R6 is thyminyl, benzyloxymethyl thyminyl, uracilyl, 5methylcytosinyl, adeninyl, Nbenzoyladeninyl, N(Nmethyl2pyrrolidinylidene)5methylcytosιnyl, hydroxy, or OCOR19 where R19 is methyl or ethyl, or together with R5 denotes an isopropylidenedioxy group, R7 is hydrogen, methyl, ethyl, benzyl, diphenylmethyl, tnphenyimethyl, dimethoxytπpnenylmehyl, COR20 or SO2R20 where R20 is phenyl, tolyl or naphthyl, or teπbutyldipnenylsilyl, or together with the attached oxygen atom and R° denotes an isopropylidenedioxy group, R8 and R10 are independently hydrogen, fluoπne, chlorine, hydroxy, meinyl, ethyl, methoxy, ethoxy, benzyloxy or OCOR21 wnere R2! is methyl, ethyl, phenyl or tolyl, or R8 together with R10 denotes a valence bond, and R9 and R11 are each hydrogen, R12 is hydrogen, methyl, ethyl, benzyl, or COR25 or SO2R25 wnere R25 is methyl, ethyl, phenyl, tolyl or naphthyl, R13 is hydrogen, hydroxy or OR26, OCOR26 or OSO2R26 where R26 is methyl, ethyl, benzyl, phenyl, tolyl or naphthyl, or together with R14 denotes an isopropylidenedioxy group, and R14 is hydroxy or OCOR27 where R27 is methyl or ethyl, or together with R13 denotes an isopropylidenedioxy group.
14. A compound according to claim 1 where R1 is hydrogen, methyl, methyl subsnruted by P(O)(OCH;CH3)2, phenyl, a group of formula HI where R28 is hydrogen or methyl and R29 and R30 are each ethyl, or a group of formula HIA where R31 and R32 are each methyl and R is hydrogen or teπbutyldimethylsilyl, R2 is methyl, hydroxy, methoxy, ethoxy, 2cyanoethoxy, or isobutoxy, or together with R5 denotes an oxy group, R3 is hydrogen, hydroxy, acetoxy, trimethylsilyloxy or ptolyloxythiocar bonyloxy, R4 is hydrogen, R5 is hydroxy, acetoxy, tenbutyldiphenylsilyloxy, thexyldimethylsilyloxy or together with R2 denotes an oxy group and R6 is hydroxy, acetoxy, thyminyl, Nbenzyloxymethylthyminyl, uracilyl, 5methylcytosιnyl, adeninyl, Nbenzoyladeninyl, or N(Nmethyl2pyπoIidinyUdene)5methylcytosιπyl or R5 and R6 together denote isopropylidenedioxy; and R7 is hydrogen, benzoyl, acetyl, benzyl, triphenylmethyl, dimethoxytπphenylmethyl or teπbutyldiphenylsilyl; or where R1 is a group of formula II where R8 is hydrogen or together with R10 denotes a valence bond, R9 is hydrogen, R10 is hydrogen or together with R8 denotes a valence bond, R11 is hydrogen, R12 is hydrogen, methyl, benzyl, benzoyl, naphthoyl or acetyl, R13 is hydrogen, hydroxy or acetoxy and R14 is hydroxy or acetoxy or R13 and R14 together denote isopropylidenedioxy, R2 is hydroxy, ethoxy or isobutoxy, R3 and R4 are hydrogen, R3 is hydroxy or acetoxy and R6 is hydroxy or acetoxy, or R3 and R6 together denote isopropylidenedioxy, and R7 is hydrogen, benzoyl, acetyl, benzyl, triphenylmethyl, dimethoxytriphenylmethyl or tenbutyl diphenylsilyl.
15. A compound according to claim 1 which is formula where R°, R2, R3, R4 and R7 are as defined in any of claims 1 to 4 and 8 to 14, Rl is hydrogen, R^ or a group of formula where R8 to R12 are as defined in any of claims 1 to 4 and 8 to 14, R3 is hydrogen, halogen, hydroxy, R18, OR18, OCOR18, OSO2R18, tri (CrC15 hydrocarbyl)silyloxy or Z as hereinbefore defined, or together with R2 denotes an oxy group, R6 is halogen, hydroxy, OR19, OCOR19. OS R19 or B1, R13 is hydrogen, halogen, hydroxy, R26, OR26, OCOR26, OSO2R26, tτi(CrC15 hydrocarby silyl or Z and R14 is halogen, hydroxy, OR27, OCOR27, OSOjR27 or B2 where R18, R19, R26, R27, B1, B2 and Z are as defined in any of claims 1 to 4 and 8 to 14; or of formula 0 == P R* where R°, R2, R3, R4 and R7 are as defined in any of claims 1 to 4 and 8 to 14„ R1 is hydrogen, R1, or a group of formula where R8 to R12 arc as defined in any of claims 1 to 4 and 8 to 14, R5 is hydrogen, halogen, hydroxy, R18, OR18, OCOR18 or OSO2R18 or together with R2 denotes an oxy group, or together with R6 denotes a C.C15 hydrocarbylidenedioxy group, R6 is halogen, hydroxy, OR19, OCOR19 or OSO2R19, or together with R3 denotes a Q to C15 hydrocarbylidenedioxy group, R13 is hydrogen, halogen, hydroxy, R26, OR26, OCOR26 or OSO2R26, or together with R14 denotes a C,, to C15 hydrocarbylidenedioxy group and R14 is halogen, hydroxy, OR27, OCOR27 or OSO2R27, or together with R13 denotes a Cl to C^ hydrocarbylidenedioxy group, where R18, R19, R26 and R27 are as defined in any of claims 1 to 4 and 8 to 14.
16. A method of preparing a compound according to claim 1, which comprises reacting a compound of formula where R° and R3a to R7 are as defined in claim 1, with a compound of formula xπ where R1. and R2 are as hereinbefore defined, in the presence of a free radical initiator.
17. A method according to claim 16, in which the reaction is carried out at 30 to 150°C.
18. A method of preparing a compound according to claim 1 where R1 is hydrogen, which comprises hydrolysing a compound of formula I where R1 is Q to replace Q by a hydrogen atom.
19. A method of preparing a compound according to claim 1 where R1 is a group of formula II in which R13 is OCOR26 and R14 is OCOR27, where R26 and R27 are the same, and R2 is OR13, which comprises esterification of a compound of formula where R3 to R6, R7a, R8 to R11 and R15 are as hereinbefore defined, with an acid of formula R26COOH or an anhydride or acid halide thereof.
20. A method of preparing a compound according to claim 1 where R1 is a group of formula π, R2 is OR13, R5 and R6 together and R13 and R14 together each denote a Cj to C15 hydrocarbylidenedioxy group and R7 is R7a, which comprises reacting a compound of formula XIV with a compound of formula where R° is hydrogen, R3a, R4, R7a, R° to Rn, R13 are as defined in claim 1 and R34 to R37 are independently hydrogen, C to C10 alkyl, C3 to C8 cycloalkyl or C6 to C10 aryl in the presence of a free radical initiator.
21. A method of preparing a compound according to claim 1 where R° and R7 are hydrogen which comprises hydrolysis of a compound of formula I where R° is hydrogen and R7 is R7a as defined in claim 1.
22. A method of preparing a compound according to claim 1 where R° is hydrogen, R1 is R1,, R3 is hydroxy and R4 is hydrogen which comprises reacting an aldehyde of formula where R5a, R6 and R7a are as defined in claim 1, with a compound of formula XII as defined in claim 16, in the presence of a base.
23. A method of preparing a compound according to claim 1 where R° is hydrogen, R1 is R1,, R3 is hydroxy and R4 is hydrogen which comprises reaction of a compound of formula XII as defined in claim 16 with a silylating agent to give a P(II) silyl compound and reacting the P(IIT) silyl compound with an aldehyde of formula XXIII as defined in claim 1") .
24. A method of preparing a compound according to claim 1 where R3 and R4 are each hydrogen which comprises deoxygenating a compound according to claim 1 in which R3 is hydroxy and R4 is hydrogen.
25. A method of preparing a compound according to claim 1 where R°, R3 and R4 are hydrogen and R' is R^ which comprises reacting a compound of formula where R5a, R° and R'a are as defined in claim 1 and L is a leaving atom or group, with a compound of formula XII as defined in claim 16.
26. A method of preparing a compound according to claim 1 where R1 is a group of formula II in which R8 and R10 together denote a valence bond which comprises reacting a compound of formula I where R° is hydrogen, R1 is an alkyl group substituted by a phosphonic ester group, R2 is OR15, R3 and R6 together and R13 and R14 together each denote a Cj to C*,$ hydrocarbylidenedioxy group and R7 is R7a, with an aldehyde of formula where R12 is as defined in claim 1 and R3 R37 R are as defined in claim 9, in the presence of a strong base.
27. Use of a compound according to any of claims 1 to 15 where R1 is hydrogen for the preparation of a dinucleotide analogue or precursor thereof by reaction, in the presence of a free radical initiator, with a compound of formula where R8 to R13 are as defined in any of claims 1 to 4 and 8 to 15 and R14 is halogen, hydroxy, OR:7, OCOR27, OSO2R27 or B2, where R27 and B2 arc as defined in claim 1, or together with R13 denotes a Cj to C15 hydrocarbylidenedioxy group.
28. Use of a compound according to claim 1 where R1 is a group of formula π, R2 is OR15, R5 is OCOR18, R6 is OCOR19. R13 is OCOR26 and R14 is OCOR27 for the preparation of a dinucleotide analogue by giycosylation with a base of formula B'H where B1 is as defined in claim 1.
29. A compound according to claim 1, substantially as described in any of Examples 1 to 27 and 30 to 105.
30. A method of preparing a compound according to claim I substantially as described in any of Examples 1 to 27 and 30 to 105.
31. Use according to claim 27 or 28 substantially as described in any of Examples 55 to 58, 89 and 91.
32. A pharmaceutical composition comprising as active ingredient a compound of formula I according to any of claims 1 to 15 or a pharmaceutically acceptable salt thereof.
Description:
1 -

Intermediates for Dinucleotide and Oligonucleotide Analogues

This invention relates to compounds which are intermediates for dinucleotide analogues and oligonucleotide analogues, the preparation of these compounds, and their use in preparing dinucleotide analogues and their use as pharmaceuticals.

For several years there has been interest in structural analogues of natural oligonucleotides because of their utility as anti-sense probes for inhibiting gene expression in biological systems and as pharmaceuticals in the treatment of viruses such as influenza, herpes and HIV, and in the treatment of cancer. Amongst the analogues of recent interest are those in which the groups linking the sugar moieties of oligonucleotides are modified by the replacement of the 3 l and 5 1 oxy linkages by other linking groups.

WO 91/15499 describes oligonucleotides of formula

HX c where B is a nucleic acid base; A is -O- or -CH 2 -; X and Z are each -O-, -S-, -NH- or -CH 2 - where X and Z may be the same or different; V and W are =O, =S, =Se, -NH 2 , alkoxy, -OH or -SH, where V and W may be the same or different in a monomer unit; L is -H or a partner of a bonding pair, C is -OR where R is an alkyl, alkenyl or alkynyl group optionally substituted by one or more halogen, cyano, carboxy, hydroxy, nitro and/or mercapto radicals; and n is any integer.

No compounds of the above formula where X and Z are each -CH 2 - are disclosed in WO 91/15499 and there is no suggestion as to how such compounds might be prepared. The

- ? .

preparation of oligonucleotide analogues in which both the 3'oxy linkage and the 5'oxy linkage are replaced by carbon linkages has remained a significant problem. It has now been found that dinucleotide analogues, and hence oligonucleotide analogues, in which both the 3' oxy linkage and the 5' oxy linkage are replaced by carbon linkages can be obtained from certain novel intermediates. These intermediates may themselves be used as pharmaceuticals in the treatment of diseases such as cancer, viruses such as influenza, herpes and HIV, and diseases which are mediated through inhibition or activation of enzymes/receptors which recognize nucleotide 3' monophosphates as substrates or liganαs.

Accordingly, the present invention provides compounds of formula

or salts thereof, where

R° is hydrogen or together with R 7 O denotes a C r 5 hydrocarbylidenedioxy group, R l is hydrogen, R ! a or a group of formula

R 1 , is R ! b or a protecting group Q,

R' b is C r C 20 alkyl, C2-C 20 alkenyl, C 3 -C 10 cycloalkyl, C 6 -C 15 aryl, C r C l6 aralkyl or a 5- or 6- membered heterocyclic group attached by a carbon atom in the heterocyclic group to

the indicated phosphorus atom.

R 2 is R 2 a or -OR 15 or together with R 5 denotes an oxy group -O-, provided that R 2 is

-OR 15 when R 1 is a group of formula II,

R 2 a is a C j -C 2 o aliphatic group, a C 3 -CJO cycloaliphatic group, a C 6 -C 15 aromatic group, a

C 7 -C 16 araliphatic group, or a 5- or 6- membered heterocyclic group attached by a carbon atom in the heterocyclic group to the indicated phosphorus atom,

R 3 is R 3 a or Z,

R 3 a is hydrogen, halogen, hydroxy, R 16 , -OR 16 , OCOR 16 , -OSO 2 R 16 , or tri(C r C 15 hydrocarbyl)silyloxy,

R 4 is hydrogen, halogen or R 1 ,

R 5 is R 5 a or Z or together with R 2 denotes an oxy group -O-, R 5 a is hydrogen, halogen, hydroxy, R 18 , -OR 18 , -OCOR 18 , -OSO 2 R 18 , or tri(C r C 15 hydrocarbyl.silyloxy, or together with R 6 denotes a C Cj 5 hydrocarbylidenedioxy group,

R 6 is halogen, hydroxy, -OR 19 , -OCOR 19 , -OSO 2 R 19 or B 1 , or together with R 5 denotes a

C r C 15 hydrocarbylidenedioxy group, provided that R 6 is not B 1 when R 1 is a group of formula II in which R 14 is B 2 ,

R 7 is hydrogen or R 7 a ,

R 7 a is R 20 , -COR 20 , -SO 2 R 20 or t_-(C r 5 hydrocarbyl)silyl, or together with the attached oxygen atom and R° denotes a C..-C..5 hydrocarbylidenedioxy group,

R 8 is hydrogen, halogen, hydroxy, R 21 , -OR 21 , -OCOR 21 , -OSO 2 R 21 or together with R 10 denotes a valence bond,

R 9 is hydrogen, halogen or R 22 ,

R 10 is hydrogen, halogen, hydroxy, R 23 , -OR 23 , -OCOR 23 or -OSO2R 23 , or together with

R 8 denotes a valence bond,

R 11 is hydrogen, halogen or R 24 ,

R 12 is hydrogen or R 12 a , or R 12 O- together with R 13 denotes a C r C 15 hydrocarbylidenedioxy group,

R 12 a is R 25 , -COR 25 , -SU 2 R 25 or tri(C r C 15 hydrocarbyl) silyl,

R 13 is R 13 a or Z,

R 13 a is hydrogen, halogen, hydroxy, R 26 , -OR 26 , -OCOR 26 , -OSO 2 R 26 or tri(C r C 15 hydrocarbyl)silyloxy, or together with R 14 denotes a C j -C^ hydrocarbylidenedioxy group, or together with R 12 O- denotes a C1.-C 1 5 hydrocarbylidenedioxy group,

R 14 is halogen, hydroxy, -OR 27 , -OCOR 27 , -OSO j R 27 or B 2 or together with R 13 denotes a

Cι-C 15 hydrocarbylidenedioxy group, provided that R 14 is not B 2 when R 6 is B 1 ,

R 13 is hydrogen or R 15 a ,

R 15 t is a Cj to CJO aliphatic group, a C 3 to C 8 cycloaliphatic group, a C 6 to C 1 5 aromatic group or a C to C 16 araliphatic group,

R 16 , R 17 , R 18 , R 19 , R 20 . R 21 , R 22 , R 23 , R 24 , R 25 , R 26 and R 27 are independently a C,_ to C 10

aliphatic group, a C 3 to C 10 cycloaliphatic group, a C 6 to C 15 aromatic group or a C 7 to

C 30 araliphatic group,

B 1 and B 2 are independently each a monovalent nucleoside base radical, and

Z is substituted or unsubstituted C 6 to C 10 aryloxythiocarbonyloxy.

In compounds of formula I, generally the aliphatic groups are substituted or unsubstituted alkyl or alkenyl groups, the cycloaliphatic groups are substituted or unsubstituted cycloalkyl groups, the aromatic groups are substituted or unsubstituted aryl groups and the araliphatic groups are substituted or unsubstituted aralkyl groups. Suitable substituents include halogen, hydroxy, etherified hydroxy, esterified hydroxy, cyano, nitro, amino, C^Cg alkylamino, di (C r Cg alkyl)amino or phosphonic ester groups.

The substituted or unsubstituted alkyl groups may be, for example, substituted or unsubstituted methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, ten-butyl, n-pentyl, neopentyl, n-hexyl, n-octyl, 2-e.hylhexyl or n-decyl. R 1 or R 2 as substituted or unsubstituted Cj to C 20 alkyl may additionally be, for example, substituted or unsubstituted n-dodecyl, n-tetradecyl, n-hexadecyl, n-octadecyl or eicosyl.

The substituted or unsubstituted alkenyl groups may be, for example, substituted or unsubstituted vinyl, allyl, 1-propenyl, isopropenyl, methallyl, 2-butenyl, 1-butenyl, isobutenyl, pentenyl, hexenyl, octenyl or decenyl. R l or R 2 as substituted or unsubstituted alkenyl may additionally be, for example, dodecenyl, hexadecenyl, octadecenyl or eicosenyl.

The substituted or unsubstituted cycloalkyl groups may be, for example, substituted or unsubstituted cyclopropyl, cyclobutyl, cyclopentyl, methylcyclopentyl, cyclohexyl, methylcyclohexyl, dimethylcyclohexyl, tert-butylcyclohexyl, cycloheptyl or cyclooctyl. The substituted or unsubstituted aryl groups may be, for example, substituted or unsubstituted phenyl, o-tolyl, m-tolyl, p-tolyl, o-xylyl, m-xylyl, p-xylyl, alpha-naphthyl, beta-naphthyl, dimethylnaphthyl or anthryl.

R 1 , R 2 or R 15 as substituted or unsubstituted C to Cι 6 aralkyl may be, for example, substituted or unsubstituted benzyl, 4-methylbenzyl, 2-phenylethyl, 2-phenylpropyl, 3-phenylpropyl or diphenylmethyl. The other substituted or unsubstituted C 7 to C30 aralkyl groups may be, for example, substituted or unsubstituted benzyl, 4-me-hylbenzyl, 2-phenylethyl, 2-phenylpropyl, 3-phenylpropyl, diphenylmethyl or triphenylmethyl.

Preferably, the alkyl groups are C x to Cg alkyl, the alkenyl groups are C 2 to C 4 alkenyl, the

cycloalkyl groups are C 5 to C 8 cycloalkyl. the aryl groups C 6 to C 10 aryl, the C 7 to C J6 aralkyl group is C 7 to C aralkyl and the C 7 to C 30 aralkyl groups are C 7 to C 2 o aralkyl, any of which are substituted or unsubstituted. More preferably, these groups are unsubstituted or substituted by halogen, hydroxy, C.. to C 4 alkoxy, cyano, nitro, amino, C j to C 4 alkylamino, di(C r C 4 alkyl) amino, or, in the case of R 1 as Cj to C 8 alkyl, by a phosphonic ester group. Especially preferred are the unsubstituted groups and, for R 1 , methyl substituted by a diethylphosphonate group, i.e. a group of formula -P(O)(OCH 2 CH 3 ) 2 and, for R 15 , C j to C 8 alkyl substituted by cyano.

When R 1 in formula I is a protecting group Q, this may be any group which is known to be effective in proieciing P-H bonds whilst reactions are carried out which would affect such bonds and be readily removable after such reactions to generate a P-H bond. Such protecting groups may be, for example, those in compounds of formula la of EP 0009348, or those in compounds described in Aust. J. Chem. 33, 292 (1980) or US 4 933 478. Preferred protecting groups Q are Cj to C 2 o hydrocarbyl groups, preferably alkyl groups, substituted on the carbon atom thereof attached to the indicated phosphorus atom by at least one hydroxy, Cι-C 10 alkoxy, di(C C 15 hydrocarbyl)silyloxy or tri(Cι-Cι 5 hydrocarbyl)silyloxy group, including those of formulae

where R 28 is hydrogen, C r C 10 alkyl, C 3 -C 8 cycloalkyl, C 6 -C 10 aryl or C 7 -C π aralkyl, R 29 and R 30 are independently Cχ-C ϊ0 alkyl, C 2 -C 4 alkenyl, C 6 -C. 0 aryl or C 7 -C 13 aralkyl R 31 and R 32 are independently C r C 10 alkyl, or R 31 is C r C 10 alkyl and R 32 is C 6 -C 10 aryl, and R 33 is hydrogen, di(Cι-C 15 hydrocarbyl)silyl or -ri(C 1 -C 15 hydrocarbyl)silyl. Preferred groups of formula HI are those where R 28 is hydrogen or C ! -C 4 alkyl and R 29 and R 30 are each C..-C 4 alkyl. Preferred groups of formula ϋlA are those where R 31 and R 32 are -C alkyl, and R 33 is hydrogen or branched C 2 -C 10 alkyl di(C r C 4 alkyl)silyl. In especially preferred compounds, Q is a group of foπnula HI where R 28 is hydrogen or methyl and R 29 and R 30 are each methyl or ethyl or a group of formula HIA where R 31 and R 32 are each methyl and R 33 is hydrogen or ten-butyl dimethylsilyl.

When a hydrocarbyl)silyloxy group is present in compounds of formula I, the hydrocarb> Dsilyl radical may be, for example, trialkylsilyl such as trimethylsilyl, triethysilyl, tri-n-propylsilyl, tri-isopropysilyl, tri-n-butylsilyl, tri-isobutysilyl, tri-teπ-butylsilyl, isopropyldimethylsilyl, ten.butyldimethylsilyl or l,l,2,2-te_ramethylethyldimethylsilyl (thexyldimethylsilyl), aryldialkylsilyl such as phenyldimethylsilyl, phenyldiethylsilyl, phenyldiisopropylsilyl or phenyl di-teπ-butylsilyl, or alkyldiarylsilyl such as isopropyldiphenylsilyl or teπ-butyldiphenylsilyl, preferably tri(C ! -C 6 alkyl)silyl, especially trimethylsilyl, C C 6 alkyldi(C 6 -C 8 aryl)silyl, especially teπ-butyldiphenylsilyl, or branched Ci- o alkyl di (C r C 4 alkyl)silyl, especially thexyldimethylsilyl.

When a C C 15 hydrocarbylidenedioxy group is present in compounds of formula I, this may be a group of formula

where R 34 , R 35 , R 36 and R 37 are independently hydrogen, C * . to C 10 alkyl, C 3 to C 8 cycloalkyl or C 6 to C 10 aryl. Preferred such groups are those where R 34 , R 35 , R 36 and R 37 are C j to C 4 alkyl, particularly methyl or ethyl. An especially preferred -C 15 hydrocarbylidenedioxy group is an isopropylidenedioxy group.

R 3 , R 5 or R 13 as substituted or unsubstituted C 6 -CJO aryloxythiocarbonyloxy may be, for example, substituted or unsubstituted phcnyloxythiocarbonyloxy, preferably C j -C 4 alkyl- or halogen- substituted phenyloxythiocarbonyloxy. especially p-tolyloxythiocarbonyloxy or pentafluorophenoxythiocarbonyloxy.

R 6 or R 14 as a monovalent nucleoside base radical B 1 or B 2 respectively may be a radical of a naturally occuring nucleoside base, such as adeninyl, cytosinyl, thyminyl, guaninyl or uracilyl, which may be unsubstituted or substituted, for example on a carbon atom by an alkyl group, usually Cj-C 4 alkyl or on an amino nitrogen atom by an acyl group such as acetyl, an aralkyl oxyalkyl group such as benzyloxymethyl or an aracyl group such as benzoyl or nitrobenzoyl, or a synthetic base analogue thereof, or a radical of an imine derivative of a primary amino group containing base. Preferably, R 6 or R 14 as a monovalent nucleoside base radical is unsubstituted or substituted thyminyl, uracilyl,

cytosinyl or adeninyl, especially thyminyl, N-benzyloxymethylthyminyl. uracilyl, methylcytosinyl, adeninyl, N-benzoyladeninyl, or N-(N-me-hyl-2-pyτro.idinylidene)-5-rnethy.cy.osinyl.

R 1 is preferably hydrogen, C r C 4 alkyl, especially methyl or methyl substituted by -P(O)(OCH 2 CH 3 ) 2 , C^C^ aryl, especially phenyl, a protecting group Q of formula HI or in A as hereinbefore defined, or a group of formula II as hereinbefore defined.

R 2 as R 2 a is preferably Cj to C alkyl, more preferably methyl or ethyl; C 2 to C 4 alkenyl, more preferably vinyl or allyl; C 5 to C 8 cycloalkyl, more preferably cyclopentyl, cyclohexyl or methylcyclohexyl; C 6 to C 10 aryl, more preferably phenyl, tolyl or naphthyl; or C 7 to C 9 aralkyl, more preferably benzyl. R 2 as R 2 a is especially eihyl.

In compounds where R 2 is -OR 15 , R 15 may be hydrogen, or substituted or unsubstituted Cj to C 8 alkyl, C 2 to C 4 alkenyl or C 7 to C 13 aralkyl, for example n-hexy , n-octyl, 2-(tri(C 1 -C 15 hydrocarbyl)silyl)ethyl, 2-(C ! -C alkoxy)ethyl, allyl, benzyl or p-methoxybenzyl. R 15 is preferably hydrogen or unsubstituted or substituted C j -C 4 alkyl, especially hydrogen, methyl, ethyl, 2-cyanoethyl or isoburyl.

Preferably R 3 is hydrogen, halogen (usually fluorine or chlorine), hydroxy, -OCOR 16 or OSO 2 R 16 where R 16 is substituted or unsubstituted C j to C 4 alkyl or C 6 to C 10 aryl (more preferably methyl, ethyl, phenyl, tolyl or naphthyl), trK -Cg alkyl)silyloxy or Cj-C 4 alky!- or halogen- substituted phenyloxythiocarbonyloxy, and R 4 is hydrogen or halogen. In some especially preferred compounds R 3 is hydrogen, hydroxy, trimethylsilyloxy, acetoxy or p-tolyloxythiocarbonyloxy and R 4 is hydrogen.

R 5 is preferably hydrogen, hydroxy or -OR 18 , -OCOR 18 or -OSO 2 R 18 where R 18 is unsubstituted or substituted Cj to C alkyl (more preferably methyl or ethyl) or unsubstituted or substituted C 6 to CJ Q aryl (more preferably phenyl, tolyl or naphthyl), tri(C j -Ci 5 hydrocarbyl)silyloxy, or together with R 2 denotes an oxy group, or together with R 6 denotes a hydrocarbylidenedioxy group of formula IV where R 34 and R 35 are independently C j to C 4 alkyl. In certain especially preferred compounds, R 5 is hydrogen, hydroxy, acetoxy, ten-butyldiphenylsilyloxy, thexyldimethylsilyloxy, or together with R 2 denotes an oxy group, or together with R 6 denotes an isopropylidenedioxy group.

R 6 is preferably a monovalent nucleoside base radical B 1 as hereinbefore defined, more preferably unsubstituted or substituted thyminyl, uracilyl, cytosinyl or adeninyl, hydroxy or -OCOR 19 where R 19 is unsubstituted or substituted Cj to C 4 alkyl, more preferably

methyl or ethyl, or together with R 5 denotes a hydrocarbylidenedioxy group of formula IV where R 34 and R 35 are independently to C 4 alkyl. In certain especially preferred compounds, R 6 is thyminyl, N-benzyloxymethylthyminyl, uracilyl, 5-methylcytosinyl, adeninyl, N-benzoyladeninyl, N-(N-methyl-2-pyτTOlidinylidene)-5-methylcytosinyl, hydroxy or acetoxy, or together with R 5 denotes an isopropylidenedioxy group.

R 7 is preferably hydrogen, substituted or unsubstituted to C 4 alkyl (more preferably methyl or ethyl), substituted or unsubstituted C 7 to C 2Q aralkyl (more preferably benzyl, diphenylmethyl, triphenylmethyl, methoxytriphenylmethyl or dimethoxytriphenylmethyl), -COR 20 or -SO 2 R 20 where R 20 is substituted or unsubstituted C l to C 4 alkyl or substituted or unsubstituted C 6 to C 10 aryl (more preferably phenyl, tolyl or naphthyl), or ( to C 6 alkyl) di (C 6 -Cg aryl) silyl, or together with the attached oxygen atom and R° denotes a hydrocarbylidenedioxy group of formula IV where R 34 and R 35 are independently C j to C 4 alkyl. In certain especially preferred compounds, R 7 is hydrogen, benzoyl, acetyl, benzyl, triphenylmethyl, dimethoxytriphenylmethyl, ten-butyldiphenylsilyl or together with the attached oxygen atom and R° denotes an isopropylidenedioxy group.

R 8 is preferably hydrogen, halogen (usually fluorine or chlorine), hydroxy, to C alkyl (more preferably methyl or ethyl), Cj to C 4 alkoxy (more preferably methoxy or ethoxy), C 7 to C 9 aralkyloxy (more preferably benzyloxy), or -OCOR 21 or -OSO 2 R 21 where R 21 is C j to C 4 alkyl, particularly methyl or ethyl, or C 6 to Cι,o aryl, particularly phenyl or p-tolyl, or together with R 10 denotes a valence bond and R 9 is hydrogen, halogen (usually fluorine or chlorine) or C to C 4 alkyl, particularly methyl or ethyl. In especially preferred compounds, R 8 is hydrogen or together with R 10 denotes a valence bond, and R 9 is hydrogen.

Preferably R 10 is hydrogen, halogen (usually fluorine or chlorine), hydroxy, C j to C alkyl (more preferably methyl or ethyl), Cj to C 4 alkoxy (more preferably methoxy or ethoxy), C 7 to Cg aralkyloxy (more preferably benzyloxy), or -OCOR 23 or -OSO 2 R 23 where R 23 is Cj to C 4 alkyl, particularly methyl or ethyl, or C 6 to C l0 aryl, particularly phenyl or p-tolyl, or together with R 8 denotes a valence bond and R 11 is hydrogen, halogen (usually fluorine or chlorine) or C ! to C 4 alkyl, particularly methyl or ethyl. In especially preferred compounds, R 10 is hydrogen or together with R 8 denotes a valence bond, and R 1 ! is hydrogen.

R 12 is preferably hydrogen, Cj to C 4 alkyl (more preferably methyl or ethyl), C to C aralkyl (more preferably benzyl), or -COR 25 or -SO 2 25 where R 25 is substituted or unsubstituted C l to C 4 alkyl (more preferably methyl or ethyl) or substituted or

unsubstituted C 6 to C^ aryl (more preferably phenyl, tolyl or naphthyl). In some especially preferred compounds, R 12 is hydrogen, methyl, benzyl, acetyl, benzoyl or naphthoyl.

R 13 is preferably hydrogen, hydroxy or -OR 26 , -OCOR 26 or -OSO^ 26 where R 26 is substituted or unsubstituted to C 4 alkyl (more preferably methyl or ethyl), substituted or unsubstituted C 7 to C !3 aralkyl (more preferably benzyl) or substituted or unsubstituted C 6 to C 10 aryl (more preferably phenyl, tolyl or naphthyl), or together with R 14 denotes a hydrocarbylidenedioxy group of formula IVA where R 36 and R 37 are independently C r to C 4 alkyl. In certain especially preferred compounds, R 13 is hydrogen, hydroxy or acetoxy, or together with R 14 denotes an isopropylidenedioxy group.

Preferably. R 14 is hydroxy or -OCOR 27 where R 27 is substituted or unsubstituted to C 4 alkyl (more preferably methyl or ethyl), or together with R 13 denotes a hydrocarbylidenedioxy group of formula IVA where R 36 and R 37 are independently Cj to C 4 alkyl. In cenain especially preferred compounds, R 14 is hydroxy or acetoxy, or together with R 13 denotes an isopropylidenedioxy group.

More especially preferred compounds of the invention are compounds of formula I where R 1 is hydrogen, methyl, methyl substituted by -P(O)(OCH CH 3 ) 2 , phenyl, a group of formula ffl where R 28 is hydrogen or methyl and R 29 and R 30 are each ethyl, or a group of formula HIA where R 31 and R 32 are each methyl and R 33 is hydrogen or teπ-butykϋmethylsilyl, R 2 is methyl, hydroxy, methoxy, ethoxy, 2-cyanoethoxy or isobutoxy. or together with R 5 denotes an oxy group, R 3 is hydrogen, hydroxy, acetoxy, trimethyls-iyloxy or p-tolyloxythiocarbonyloxy, R 4 is hydrogen, R 5 is hydroxy, acetoxy, tert-butylc-iphenylsilyloxy, thexyldimethylsilyloxy or together with R 2 denotes an oxy group and R 6 is hydroxy, acetoxy, thyminyl, N-benzyloxymethylthyminyl, uracilyl, 5-methylcyιosinyl, adeninyl, N-benzoyladeninyl, or

N-(N-methyl-2-pyτrolidinylidene)-5-methylcytosinyl or R 5 and R 6 together denote isopropylidenedioxy; and R 7 is hydrogen, benzoyl, acetyl, benzyl, triphenylmethyl, dimethoxyiriphenylmethyl or ten-butyldiphenylsilyl; and compounds of formula I where R 1 is a group of formula II where R 8 is hydrogen or together with R 10 denotes a valence bond, R 9 is hydrogen. R 10 is hydrogen or together with R 8 denotes a valence bond, R 11 is hydrogen. R 12 is hydrogen, methyl, benzyl, benzoyl, naphthoyl or acetyl, R 13 is hydrogen, hydroxy or acetoxy and R 14 is hydroxy or acetoxy or R 13 and R 14 together denote isopropylidenedioxy, R 2 is hydroxy, ethoxy or isobutoxy, R 3 and R 4 are hydrogen, R 5 is hydroxy or acetoxy and R 6 is hydroxy or acetoxy, or R 5 and R 6 together denote isopropylidenedioxy, and R 7 is hydrogen, benzoyl, acetyl, benzyl, triphenylmethyl,

dimethoxy triphenylmethyl or ten-butyl diphenylsilyl.

Compounds of the invention may be in the form of one of the possible isomers, for example as a diastereomer, an optical isomer or a racemate, or a mixture thereof.

Preferred isomers of compounds of formula I are those of formula

where R°, R 2 , R 3 , R 4 and R 7 are as hereinbefore defined, R 1 is hydrogen, R 1 , or a group of formula

where R 8 to R 12 are as hereinbefore defined, R 5 is hydrogen, halogen, hydroxy, R 18 , -OR 18 , -OCOR 18 , -OSO : R 18 , tri (C r C 15 hydrocarbyl)silyloxy or Z as hereinbefore defined, or together with R 2 denotes an oxy group, R 6 is halogen, hydroxy, -OR 19 , -OCOR 19 , -OSO 2 R 19 or B 1 as hereinbefore defined, R 13 is hydrogen, halogen, hydroxy, R 26 , -OR 26 , -OCOR 26 , -OSO2R 26 , tri(C r Ci5 hydrocarbyDsilyl or Z as hereinbefore

defined and R 14 is halogen, hydroxy, -OR 27 , -OCOR 27 , -OSO 2 R 27 or B 2 as hereinbefore defined, and those of formula

0 :

where R°, R 2 , R 3 , R 4 and R 7 are as hereinbefore defined, R 1 is hydrogen, R^ or a group of formula

where R 8 to R 12 are as hereinbefore defined, R 5 is hydrogen, halogen, hydroxy, R 18 , -OR 18 , -OCOR 18 or -OSO 2 R 18 as hereinbefore defined or together with R 2 denotes an oxy group, or together with R 6 denotes a CJ-C- hydrocarbylidenedioxy group, R 6 is halogen, hydroxy, -OR 19 , -OCOR 19 or -OSO 2 R 19 as hereinbefore defined, or together with R 5 denotes a to C 15 hydrocarbylidenedioxy group, R 13 is hydrogen, halogen, hydroxy, R 26 , -OR 26 , -OCOR 26 or -OSO 2 R 26 as hereinbefore defined or together with R 14 denotes a C l to Cu hydrocarbylidenedioxy group and R 14 is halogen, hydroxy, -OR 27 , -OCOR 27 or -OSO2R 27 as hereinbefore defined or together with R 13 denotes a to 5 hydrocarbylidenedioxy group.

- 12 -

Specific especially preferred compounds are those hereinafter described in the Examples.

Compounds of formula I where R 1 is R may be prepared by reacting a compound of formula

where R° and R 3 a to R 7 are as hereinbefore defined, with a compound of formula

where R 1 , and R 2 are as hereinbefore defined, in the presence of a free radical initiator. Suitable initiators include azo compounds such as azobis (isobutyronitrile), peroxides such as benzoyl peroxide, ten-butyl peroxide or 2,2-bis(tert-butylperoxy)propane, peresters such as ten-butyl perbenzoate or ten-butyl per-2-ethylhexanoate, percarbonates such as diacetyl perdicarbonate, bis(cyclohexyl)perdicarbonate, or bis (4-tert-butylcyclohexyl)perdicarbonate or persalts such as potassium persulphate. The initiator is generally used in an amount of 0.1 to 100% mol, preferably 5 to 15, mol %, per mol of the compound r c formula XI. In general, 1 to 5 equivalents, preferably 1 to 2 equivalents, of the compound of formula XII are used per equivalent of the compound of formula XI. The reaction may be carried out without a solvent, but is preferably carried out in an organic solvent, usually an aromatic hydrocarbon such as benzene, toluene or xylene. It may be carried out at temperatures of 30 to 150°C preferably 70 to 100°C.

Compounds of formula XI where R 3 a and R 4 are each hydrogen and R s a and R 6 together denote a to C 15 hydrocarbylidenedioxy group can be obtained by a Wittig reaction of a

ketone of formula

where R°, R 7 a , R 34 and R 35 are as hereinbefore defined, with a methyltriphenylphosphonium salt and an alkyllithium, usually at a -emper-uurc increasing from within the range -60 to -80°C to ambient temperature, the resulting reaction mixture being acidified, usually with acetic acid. The reaction may be carried out in an organic solvent, for example tetrahydrofuran, a hydrocarbon such as hexane or a mixture thereof.

Compounds of formula XI where R 3 a and R 4 are each halogen and R 5 a and R 6 together denote a Cj to C 15 hydrocarbylidenedioxy group can be obtained by analogous reactions of compounds of formula XIII. Reaction of such compounds with carbon tetrachloride and triphenylphosphine in acetonitrile using the procedure described by J.M.J. Tronchet et al, Eur. J. Med. Chem - Chim. Ther. 11 (6), 489 (1976), gives compounds of formula XI where R 3 a and R 4 are each chlorine. Reaction of compounds of formula XHI with --ibromodifluromethane, hexamethylphosphorus triamide and zinc in tetrahydrofuran gives compounds of formula XI where R 3 a and R 4 are each fluorine.

Compounds of formula XIII where R° is hydrogen may be prepared from -C 15 hydrocarbylidenexy loses such as 1,2-isopropylidenexylose by reaction of the primary alcohol group with a compound of formula R 7 a X or (R^CO^O where R 7 a and R 20 are as hereinbefore defined and X is a halogen atom or a hydroxyl group, to convert the methylol group into a group -CH 2 OR 7 a or -CH 2 OCOR 20 , and reacting the product with an oxidising agent such as pyridinium dichromate, usually at 30-40°C in the presence of a dehydrating agent such as acetic anhydride and in an inert solvent such as methylene chloride to convert the 3'-hydroxyl group into a keto group. A suitable procedure is described by H.S. Mosher et al, J. Org. Chem 51,2702 (1986). Compounds of formula XH where R° and R 7 a O together denote a C \ to Cγζ hydrocarbylidenedioxy group may be prepared by reaction of glucose with a ketone of formula R 34 CO R 35 and oxidising the 3' hydroxy group of the di(hydrocarbylidenedioxy) reaction product as hereinbefore described.

The compounds of formula XI where R 5 a and R 6 together denote a to C 15 hydrocarbylidenedioxy group, prepared as described above, are of formula

where R°, R 3 a , R 4 , R 7 a , R 34 and R 35 are as hereinbefore defined. These compounds can be subjected to acid hydrolysis, for example by treatment with an acidic ion exchange resin, to hydrolyse the hydrocarbylidenedioxy group(s), usually at 40-100°C, to give corresponding compounds of formula XI where R 5 a and R 6 are each hydroxy and R° is hydrogen, which can in turn be esterified by reaction with an acid of formula R 18 COOH or an anhydride or acid halide thereof, to give compounds of formula XI where R 5 a is -OCOR 18 and R 6 is -OCOR 19 , R 18 and R 19 being the same. The esterification can be carried out using conventional procedures, for example using anhydride or acid halide in the presence of an organic base such as pyridine, dimethylaminopyridine or triethylamine, optionally in an organic solvent such as methylene chloride, an aromatic hydrocarbon such as toluene, an ether such as tetrahydrofuran or an ester such as ethyl acetate. The esterification can be effected at a temperature from -70°C to 80°C.

Compounds of formula XI where R 5 a is -OCOR 18 and R 6 is B 1 as hereinbefore defined can be prepared by giycosylation of compounds of formula XI where R 5 , is -OCOR 18 and R 6 is -OCOR 19 with a base of formula BΗ. Giycosylation is generally effected in the presence of a silylating agent such as trimethylsilyl chloride, bis(trimethylsilyl)acetamide or hexamethyldisilazane and a catalyst such as a fluoroalkanesulphonate salt in an organic solvent such as acetonitrile or 1,2-dichloroethane at a temperature of 40-90°C. Where the compound subjected to giycosylation contains a hydroxyl group, the giycosylation product may be reacted with an aqueous acid such as acetic acid to regenerate a hydroxyl group which has been silylated during giycosylation. The base of formula B'H is a readily available nucleoside base such as adenine, cytosine, guanine, thymine or uracil or a substituted derivative or analogue thereof prepared by known procedures.

Compounds of formula XI where R 5 a is hydroxy and R° and R 7 are hydrogen can be obtained by hydrolysis of a compound of formula XI in which R° is hydrogen, R 5 a is -OCOR 18 and R 7 is R 7 a using known procedures. Compounds of formula XI where R 5 a is halogen may be prepared by nucleophilic displacement reactions of compounds of formula XI where R 5 a is hydroxy, using known procedures. Compounds of formula XI where R 5 a is -OR 18 or _ri(C r C 15 hydrocarbyl)silyloxy can be prepared by etherification of compounds of formula XI where R 5 a is hydroxy, using known etherification procedures.

Compounds of formula XII where R 1 , is a protecting group Q of formula III as hereinbefore defined and R 2 is -OR 15 a where R 15 a is as hereinbefore defined are protected phosphinate esters which can be prepared by known methods, for example as described in EP 0 009 348, US 4 933 478 or Aust. J. Chem. 33,212 (1980).

Compounds of formula XII where R 1 , is a protecting group Q of formula IIIA as hereinbefore defined and R 2 is -OR 15 a where R 15 a is as hereinbefore defined are protected phosphinate esters, which can be prepared by esterifying a phosphinic acid of formula

,31 o

HO XV

R 32 OH with an alcohol of formula R 15 a OH where R 15 a , R 31 and R 32 are as hereinbefore defined.

The esterification may be carried out at -20 to 30°C, preferably 0 to 10°C. It is conveniently carried out in a solvent, preferably an ether such as tetrahydrofuran, preferably in the presence of a base, usually a tertiary amine such as dimethylaminopyridine, and a dehydrating agent such as N, N'-dicyclohexylcarbodiimide.

Phosphinic acids of formula XV can be prepared by reacting hypophosphorous acid with a ketone of formula

where R- : and R 32 are as hereinbefore defined, or by reacting hypophosphorous acid with a ketal of this ketone using the procedure described by S. J. Fitch, J. Amer. Chem. Soc. 86, 61(1964), followed by hydrolysis of the resulting phosphonous ester, for example by heating with water.

Compounds of formula XII where R l t is R and R 2 is R 2 a , where R^ and R 2 a are as hereinbefore defined, are phosphine oxides which are either commercially available or may be prepared by conventional methods. Compounds of formula XII where R ! a is a protecting group Q of formula HI as hereinbefore defined and R 2 is R 2 a as hereinbefore defined are protected phosphine oxides which can be prepared by reacting a protected phosphinate ester of formula

xvπ

OR 38 where R 38 is C C alkyl and Q is a group of formula HI as hereinbefore defined, with an organomagnesium halide of formula R 2 a Mg X or an organolithium of formula R 2 _Li, where R 2 a and X are as hereinbefore defined.

Compounds of formula XII where R 1 , is alkyl, particularly methyl, substituted by a phosphonic ester group, and R 2 is -OR 15 , as hereinbefore defined, may be prepared by reacting a phosphinate ester of formula

- 17

o ===== p R 39 XVΠA

OR 38 where Q is a protecting group Q of formula III as hereinbefore defined, R 38 is as hereinbefore defined and R 39 is a C r C 4 alkyl group, preferably methyl, with a strong base such as an alkyllithium, an alkali metal hydride or an alkali metal amide to deprotonate the ester of formula XVIIA and reacting the resulting anionic species with a halophosphonic ester such as diethyl chlorophosphate. Both reactions are generally carried out in an organic solvent, usually an ether such as tetrahydrofuran. Deprotonation is usually effected at a temperature from -100°C to -15°C and reaction with the halophosphonic ester at -100 to 30°C.

Compounds of formula I where R 1 is hydrogen may be prepared by hydrolysis of compounds of formula I where R 1 is a protecting group Q to replace Q by a hydrogen atom. This hydrolysis may be carried out using known procedures. For example, where the protecting group Q is of formula HI, it may be effected by reaction with a trialkylsilyl halide such as trimethylsilyl chloride, trimethylsilyl bromide or trimethylsilyl iodide. The reaction may be carried out at a temperature of -30°C to 100°C, preferably 0 to 40°C, preferably under anhydrous conditions, in an organic solvent, for example a halohydrocarbon such as chloroform or trichloroethane, an ether such as tetrahydrofuran or an aromatic hydrocarbon such as benzene, toluene or xylene, or a mixture of two or more of such solvents. When a trialkylsilyl chloride is used, the reaction is carried out in the presence of an alcohol such as ethanol. When R 2 in formula I is -OR 15 a , this group may also be affected by the hydrolysis: in general, use of a trialkylsilyl chloride gives a product in which R 15 a is unchanged, while use of a trialkylsilyl iodide gives a product in which R 15 a is replaced by hydrogen. When a trialkylsilyl bromide is used, a mixture of a compound in which R 2 is -OH and a compound in which R 2 is -OR 15 , is generally obtained.

Hydrolysis of compounds of formula I where R 1 is Q, to replace Q by a hydrogen atom, can also be effected by treatment with an acid, preferably under anhydrous conditions. It may be carried out with a mineral acid such as hydrochloric acid, in which case when R 2 is -OR 15 , it is also hydrolysed to -OH, or with an organic acid such as acetic acid, in which case when R 2 is -OR 15 , the product may be a compound in which R 2 is -OR 15 ,, a compound in which R 2 is -OH or a mixture thereof.

18

When R 1 in formula I is a protecting group Q of formula IIIA, hydrolysis to replace Q by a hydrogen atom can be effected by treatment with a base, for example by treatment with aqueous ammonia or a hindered base such as triethylamine or 1 , 8-diazabicyclo[5.4.0]undec-7-ene(DBU), optionally in the presence of alcoholic/aqueous solvent, at a temperature from ambient temperature to 100°C. When R 2 in formula I is -OR 15 a , this group is also affected by the basic hydrolysis; for example, when ammonia, DBU or an alkali metal hydroxide or carbonate is used for the hydrolysis, R 15 a is replaced by ammonium or an alkali metal ion respectively which in turn is replaced by hydrogen on acidification of the basic hydrolysis product. The resulting hydroxyl group can be re-esterified, if desired, for example by reaction with an alkyl chloroformate in the presence of a tertiary amine or by reaction with an alcohol and a carbodiimide such as dicyclohexylcarbodiimide, optionally in the presence of a base such as 4-dime-hy-aminopyridine.

Compounds of formula I where R 1 is hydrogen may be used in the preparation of dinucleotide analogues and precursors thereof, some of which precursors are novel compounds of formula I where R 1 is a group of formula II (R 14 being other than B 2 and R 2 being -OR 15 ). Accordingly, the present invention also provides the use of compounds of formula I where R 1 is hydrogen for the preparation of dinucleotide analogues or precursoπ thereof by reaction, in the presence of a free radical initiator, with a compound of formula

where R 8 to R 13 arc as hereinbefore defined and R 14 is halogen, hydroxy, -OR 27 , -OCOR 27 , -OSO 2 R 27 or B 2 , where R 27 and B 2 are as hereinbefore defined, or together with R 13 denotes a Cj to Cu hydrocarbylidenedioxy group. The free radical initiator and the reaction conditions may be as hereinbefore described for the reaction of compounds of formulae XI and XII. When R 2 is -OR 15 in the reactant of formula I where R 1 is hydrogen and R 14 is other than B 2 in the compound of formula XVIII when R 6 in the reactant of formula I is B 1 , the product is a compound of the invention where R 1 is a group of formula

II as hereinbefore defined.

Compounds of formula XVIII where R 8 to R 10 are hydrogen and R 13 and R 14 together denote a C j to C^ hydrocarbylidenedioxy group can be prepared by reacting a compound of formula

,35

where R 34 to R 37 are as hereinbefore defined, with a compound of formula R 12 a X or (R 25 CO) 2 θ, where R 12 , R 25 and X are as hereinbefore defined, to etherify or esterify the hydroxyl group and reacting the product with 80% acetic acid at ambient temperature to give a compound of formula

where R 12 „ R 36 and R 37 are as hereinbefore defined, reacting the compound of formula XX with methanesulphonyl chloride in the presence of a base to replace both of the indicated hydroxyl groups by methane sulphonyloxy groups, and reacting the product with sodium iodide in methyl ethyl ketone at 70-90°C to give an olefin of formula XVm where R 12 is R 12 „ which can be hydrolysed by treatment with potassium carbonate in aqueous methanol at ambient temperature to give an olefine of formula XIII where R 12 is hydrogen.

Compounds of formula XIX can be prepared using the procedure described (for the preparation of compounds where R 34 to R 37 are each methyl) in Carbohyd. Res. 24, 194-5 0972).

Compounds of formula I where R 1 is a group of formula II in which R 13 is -OCOR 26 and R 14 is -OCOR 27 , where R 26 and R 27 are the same, and R 2 is -OR 15 , can be prepared by esterification of a compound of formula

where R 3 to R 6 , R 7 ,, R 8 to R 11 and R 15 are as hereinbefore defined, with an acid of formula R^COOH or an anhydride or acid halide thereof. This esterification reaction may be carried out using conventional procedures, for example by reaction with an anhydride or acid halide in the presence of an organic base such as pyridine, dimethylaminopyridine or triethylamine, optionally in an organic solvent, for example a halohydrocarbon such as methylene chloride, an aromatic hydrocarbon such as toluene, an ether such as tetrahydrof uran or an ester such as ethyl acetate. The esterification can be effected at a temperature from -70°C to 80°C. Where, as in preferred embodiments, R 5 and R 6 in formula XXI are each hydroxy, the product is a compound of formula I in which R 5 is -OCOR 18 , R 6 is -OCOR 19 , and R 1 is a group of formula II in which R 13 is -OCOR 26 and R 14 is -OCOR 27 , R 18 , R 19 , R 26 and R 27 being the same. Compounds of formula I where R 1 is a group of formula II, R 2 is -OR 15 , R 5 is -OCOR 18 , R 6 is -OCOR 19 , R 13 is -OCOR 26 and R 14 is -OCOR 27 can be converted into dinucleotide analogues by giycosylation with a base of formula B'H where B 1 is as hereinbefore defined. Giycosylation is generally effected in the presence of silylating agent such as trimethylsilyl chloride, bis(trimethylsilyl) acetamide or hexamethyldisilazane and a catalyst such as a floroalkanesulphonate salt in an organic solvent such as acetonitrile or 1,2-dichloroethane at a temperature of 40-90°C The base of formula B'H is a readily available nucleoside base such as adenine, cytosine, guanine, thymine or uracil or a substituted derivative or analogue thereof prepared by known procedures.

Compounds of formula XXI can be prepared by acidic hydrolysis of a compound of formula I where R 1 is a group of formula II, R 2 is -OR 15 , R 5 and R 6 together and R 13 and R 14 together each denote a Cj to C 15 hydrocarbylidenedioxy group and R 7 is R 7 ,. The acidic hydrolysis can be carried out by reaction with an organic acid such as formic acid- acetic acid, trifluoroaceric acid or p-toluenesulphonic acid together with water and, optionally, an organic solvent such as dioxan or tetrahydrofuran. It may also be carried out with an aqueous inorganic acid such as hydrochloric acid or sulphuric acid. Hydrolysis with organic or inorganic acids may be effected at temperatures from -30°C to 50°C; usually it is effected at ambient temperature. The acid hydrolysis can also be carried out by heating with an acidic ion exchange resin and a mixture of water and a polar organic solvent such as dimethyl formamide or dichloromethane or an ether such as diethyl ether, tetrahydrofuran, diethoxymethane or dimethoxyethane, generally at a temperature of 40 to 100°C.

Compounds of formula I where R 1 is a group of formula II, R 2 is -OR 15 , R 5 and R 6 together and R 13 and R 14 together each denote a C j to C $ hydrocarbylidenedioxy group and R 7 is R 7 , can be prepared by reacting a compound of formula XTV as hereinbefore defined, in which R° is hydrogen, with a compound of formula

where R 8 to R 11 , R 15 , R 36 and R 37 are as hereinbefore defined, in the presence of a free radical initiator. Suitable initiators and reaction conditions may be as hereinbefore described for reaction of compounds of formula XI with those of formula XII.

Compounds of formula XXII can be prepared by reaction of an olefine of formula XVm, where R 13 and R 14 together denote a C j -C^ hydrocarbylidenedioxy group, with a phosphinate of formula XII, where R 1 , is a protecting group Q of formula HI as hereinbefore defined and R 2 is -OR 15 , as hereinbefore defined, in the presence of a free radical initiator, followed by hydrolysis to replace the protecting group Q by a hydrogen atom as hereinbefore described. The initiator and conditions for reaction of the

compounds of formulae XVIII and XII may be as hereinbefore described for reaction of compounds of formula XII with those of formula XI.

Compounds of formula I where R° and R 7 are hydrogen can be prepared by hydrolysis of compounds of formula I where R° is hydrogen and R 7 is R 7 a using known procedures, for example by reaction with a carboxylic acid such as acetic acid in the presence of a quaternary ammonium salt.

Compounds of formula I where R° is hydrogen, R 1 is R 1 -, R 3 is hydroxy and R 4 is hydrogen may also be prepared by reacting an aldehyde of formula

where R 5 ,, R 6 and R 7 , are as hereinbefore defined, with a compound of formula XII as hereinbefore defined, under basic, neutral or acidic conditions. When the reaction is carried out under basic conditions, the base is preferably a non-nucleophilic base, for example a hindered amine such as 1, 8-diazabicyclo[5.4.0]undec-7-ene (DBU) or 1.5-diazabicyclo[4.3.0]non-5-ene or an alkali metal alkoxide such as the teπ-butoxide of sodium or potassium. The reaction may be carried out at temperatures of -20 to 100°C, preferably 10 to 30°C. It is preferably effected in an organic solvent, for example a hydrocarbon such as benzene, toluene or xylene, a halohydrocarbon such as dichloroethane or methylene chloride or, preferably, an ether such as diethyl ether, dioxan or, especially, tetrahydrofuran.

When the reaction is performed under neutral conditions, compounds of formula I where R° is hydrogen, R 1 is R 1 ,, R 3 is hydroxy and R 4 is hydrogen may be prepared by reaction of a compound of formula XD with a silylating agent to give a P(HI) silyl compound and reacting the latter with an aldehyde of formula XXIH as hereinbefore defined. The silylating agent may be, for example, a dialkylhalosilane such as dimethylchlorosilane, trialkylhalosilane such as trimethylchlorosilane or triethylchlorosilane which is reacted with the compound of Formula XII in the presence of tertiary base such as pyridine or triethylamine. Another type of silylating agent which can be used is a bis(trialkylsilyl) derivative of an amide, for example bis(trimethylsilyl)acetamide or

bis(trimethylsilyl)trifluoroacetamide). The reaction between the compound of formula XII and the silane or the silyl amide may be carried out at temperatures ranging from -20°C to 150°C and can be effected with or without the use of a solvent such as diethylether, tetrahydrofuran, dioxan, dichloromethane or toluene. Alternatively, an excess of the silane can be used as diluent. The silylating agent may alternatively be hexamcthyldisilazide, which may be reacted with the compound of Formula XII in the absence of a solvent at 100-200°C. The reaction of the P(III) silyl compound with the aldehyde of formula XXIII may be carried out under conditions conventional for substitution reactions on P(III) species. It is preferably carried out by the Arbuzov method, e.g. at temperatures between ambient and elevated temperatures such as 160°C, followed by hydrolysis of the intermediate silyl species.

When the reaction between the aldehyde of formula XXIII and the compound of formula XII is carried out under acid conditions, it may be carried out in the presence of a Lewis acid such as boron trifluoride or a titanium (TV) compound, for example a titanium tetrahalide such as TiCl 4 , a titanium dialkoxidedihalide such as Ti(OiPr) 2 Cl 2 or, preferably, a titanium tetraalkoxide such as titanium tetra-isopropoxide.

Aldehydes of formula XXHI may be prepared by reaction of the corresponding S'-iodo compound with carbon monoxide and tris(trimethylsilyl)silane in the presence of a free radical initiator such as 2,2 1 -azobis(isobutyronitrile), by reduction of the corresponding 3 l -cyano compound with diisobutylaluminium hydride or otherwise as described in WO 92/20823. Aldehydes of formula XXHI may also be prepared by treatment of the corresponding S^amino compound with nitrite as described by S. Shuto et al, Nucleosides & Nucleotides, 1 (3), 263-272(1982), or by hydrolysis of the corresponding 3 1 -C-(4,5-dihydro-5-methyl-l,3,5-dithia_tin-2-yl) compound as described by Bamford et al, J. Med. Chem. 1990, 33, 2494.

Compounds of formula I in which R 3 and R 4 are hydrogen can be prepared from corresponding compounds in which R 3 is hydroxy and R 4 is hydrogen by conventional deoxygenation methods, for example by reaction with a suitably substituted reagent to allow free radical mediated cleavage, such as by reaction with a substituted or unsubstituted C 6 -C I0 aryloxythiocarbonyl chloride such as p-tolylchlorothionoformate or pentafluorophenylchlorothionoformate to conven the hydroxy group R 3 into a substituted or unsubstituted C 6 -C JQ aryloxythiocarbonyloxy group, and then removing this group by reaction with a trialkylstannane such as tri-n-butylstannane or a tris(trialkylsilyl)silane, such as tri(-rimethylsilyl)silane, in the presence of a free radical initiator such as azobis(-sobutyronitrile) or the free radical initiators hereinbefore described Such

deoxygenation can be carried out using conventional procedures. Other standard methods for the deoxygenation of alcohols are described by Haπwig, Tetrahedron 39, 2609 (1983). Similarly, compounds of formula I where R 5 and or R 13 are hydroxy may be converted, by reaction with an aryloxy thiocarbonyl chloride as described above, into compounds of formula I where R 5 and or R 13 are aryloxythiocarbonyloxy, which can then be reacted with a trialkylstannane in the presence of a free radical initiator to give compounds of formula I where R 5 and or R 13 are hydrogen.

Compounds of formula I where R 3 is halogen and R 4 is hydrogen can be prepared from those in which R 3 is hydroxy and R 4 is hydrogen by nucleophilic displacement reactions using conventional procedures.

Compounds of formula I where R°, R 3 and R 4 are hydrogen and R 1 is R ! a may also be prepared by reaction of a compound of formula

where R 5 ,, R 6 and R 7 a are as hereinbefore defined and L is a leaving atom or group, with a compound of formula XH as hereinbefore defined.

The leaving atom or group L in formula XXTV may be, for example, a halogen atom or a residue of an organic or inorganic acid after removal of an acidic hydrogen atom therefrom, such as an organic sulphonate group, e.g. a methanesulphonate, trifluoromethanesulphonate or p-toluenesulphonate, or a sulphate anion. Preferably L is a chlorine, bromine or iodine atom or an organic sulphonate group, especially an iodine atom.

The reaction between the compound of formula XXTV and the compound of formula XH may be carried out under conventional conditions for substitution reactions at a P-H bond, for example in the presence of a base such as a tertiary amine, an alkali metal (usually sodium), an organometal of an alkali metal or magnesium (usually an alkyllithium), an alkali metal hydride (usually sodium hydride), or an alkali metal amide such as lithium diisopropylamide or, especially, potassium b_s(trimethylsilyl)amide. The reaction may be

carried out in an organic solvent, usually an ether such as diethyl ether or tetrahydrofuran, a hydrocarbon such as hexane or toluene, and at a temperature from -100°C to 100°C, usually from -80°C to 40°C.

Compounds of formula XXIV may be prepared by reducing an aldehyde of formula XXIH, for example using sodium borohydride, to the corresponding alcohol, and carrying out esterification and/or nucleophilic displacement reactions on the alcohol, for example esterifying the alcohol by reaction with an organic sulphonyl chloride optionally followed by reaction with an alkali metal halide to introduce a halogen atom, or reacting the alcohol with a halogenating reagent, in particular a phosphonium halide such as methyl(triphenoxy)phosphonium iodide to replace the alcoholic hydroxyl directly by halogen. These reactions may be carried out using conventional conditions and procedures.

Compounds of formula I where R 1 is a group of formula π in which R 8 and R 10 together denote a valence bond can be prepared by reacting a compound of formula I where R° is hydrogen, R 1 is an alkyl group substituted by a phosphonic ester group, R 2 is -OR 15 , R 5 and R 6 together and R 13 and R 14 together each denote a C j to C 1 hydrocarbylidenedioxy group and R 7 is R 7 a , with an aldehyde of formula

where R 12 , R 36 and R 37 are as hereinbefore defined, in the presence of a strong base such as an alkyllithium, an alkali metal hydride, or an alkali metal amide as hereinbefore described, or a mixture of triethylamine and lithium bromide or magensium bromide. The reaction is generally carried out in an organic solvent, usually an ether such as tetrahydrofuran and at a temperature from -100°C to 0°C, or, where a mixture of triethylamine and a bromide is used, at temperatures up to 30°C - See M. Prashad, Tetrahedron Letters, 34, 1585 - 88 (1993).

Aldehydes of formula XXV are available commercially or may be prepared by known methods.

Compounds of the invention containing salt-forming groups may be in the form of pharmaceutically acceptable, i.e. physiologically tolerable, salts. For example, a compound of formula I in which R 2 is hydroxy, which is a phosphinic acid, may in the form of a pharmaceutically acceptable salt with a base. Such salts include alkali metal salts such as sodium or potassium salts, alkaline earth metal salts such as magnesium or calcium salts, or ammonium salts with ammonia or organic amines, preferably tertiary monoamines and heterocyclic bases such as triethylamine, tri(2-hydroxyethyl)amine, N-ethylpiperidine or N, N^dimethylpiperazine.

Compounds of formula I in which R 6 or R 14 is a basic group may be in the form of acid addition salts with organic or inorganic acids. Acids which form suitable salts include hydrohalic acids, for example hydrochloric and hydrobromic acid, sulphuric acid, phosphoric acid, nitric acid or perchloric acid, or aliphatic, alicyclic, aromatic or heterocyclic carboxylic or sulphonic acids, such as formic, acetic, propionic, succinic, glycolic, lactic, malic, tartaric, citric, fumaric, maleic, hydroxymaleic, oxalic, pyruvic, phenylacetic, benzoic, p-aminobenzoic, anthranilic, p-hydroxybenzoic, salicyclic, p-aminosalicyclic acid, embonic acid, methanesulphonic, ethanesulphonic, hydroxyethyanesulphonic, ethylenedisulphonic, halobenzenesulphonic, toluenesulphonic, naphthalenesulphonic and sulphanilic acids, methionine, tryptophan, lysine, arginine and ascorbic acid.

Salts of the invention may be prepared by conventional salt-forming procedures.

When mixtures of diastereomers of compounds of formula I or intermediates are obtained, these can be separated by known methods, for example by fractional distillation, crystallisation or chromatography.

The invention also relates to the use of compounds of formula I, and their pharmaceutically acceptable salts, as pharmaceuticals, particularly as anti-viral agents. Accordingly, the present in > don also provides a pharmaceutical composition comprising as active ingredient a compound of formula I or a pharmaceutically acceptable salt thereof. The composition may contain a pharmaceutically acceptable carrier such as one conventionally used in pharmaceutical compositions. The compositions may be formulated for enteral or parenteral administration.

The invention is illustrated by the following Examples. Compounds used in the Examples are prepared as follows:

Compound A

n-Butyllithlium (1.6M in hexanes, 6.9ml, 11.1 mmol) is added to a suspension of methyltriphenylphosphium bromide (3.6g, lO.Ommol) in tetrahydrofuran (THF) (25ml) at -70°C. The mixture is allowed to warm to 20°C and then cooled to -10°C, whereupon a solution of a ketone of formula XIII where R° and R 7 a O together, and R 34 and R 35 together, denote isopropylidenedioxy groups (1.3g, 5.0 mmol) in THF (5ml) and DMPU (5ml) is added. The suspension is allowed to warm to 20°C. After 18 hours, saturated aqueous ammonium chloride is added. The aqueous layer is separated and then extracted with chloroform. The combined organic phases are dried over magnesium sulphate and evaporated. The resulting material is dissolved in ethyl acetate and washed with water, before drying as above, and evaporation. The resulting material is triturated with ether and subject to chromatography on silica gel, elating with a hexane/ether gradient. The product, Compound A is obtained as an oil.

H NMR (400 MHz, CDC1 3 ) δ 5.44 (d, 1H) 5.50 (d-d, 1H) ppm.

Compound B

CH 3 OCH 3

Commercial hypophosphorous acid (50%) is concentrated to 94% on a rotary evaporator. A mixture of hypophosphorous acid (94%, 210.6g, 3M) and 2,2-dimethoxypropane (917g, 8.8M) is allowed to stand at room temperature for 6 days. The mixture is evaporated under vacuum and distilled on a wiped-wall still to give Compound B, methyl(l-hydroxy-l-methylethyl)phosphinate (268g, 65%, b.p. 65°C 0.1mm).

31 P nmr (CDCI3, 24.15 MHZ) δ = 45 ppm, J PH 545Hz. (Fitch J.Amer.Chem.Soc. 1964, 86,

- 28 -

61).

Compound C

Ph

where Ph is phenyl n-Buryilithium (1.6M in hexaner "..Oml, 19.2mmol) is added to a suspension of methylmpenylphosphonium br- de (6.35g, 17.8mmol) in THF (67ml) at -65°C. The mixture is warmed to 20°C and rec led to -65°C, whereupon a solution of a ketone of formula XIII where R° and R 7 , together, and R 34 and R 35 together, denote isopropylidenedioxy groups (5.9g, 13.8 mmol) in THF (15ml) j s added over 14 minutes. After 2.5 hours, the mixture is allowed to warm to +15°C, then stored at -10°C for 16 hours. Ammonium chloride (saturated aqueous, 0.3ml) is added to the mixture which is then filtered. The filtrate is re-filtered after the addition of ether (200ml).

The filtrate is dried over magnesium sulphate, evaporated and purified by chromatography on silica gel, eluting with a hexane/ether gradient, to give the product as an oil.

l H nmr (CDC1 3 , 60MHz) 7.40-7.95 (m,10H), 5.91 (d,lH), 5.45 (mJH), 5.21 (m,lH), 4.90-5.20 (m,2H), 3.70-3.80 (m,2H), 1.52 (s,3H), 1.40 (s,3H), 1.06 (s, 9H) ppm.

Compound D

CH 3 OCH 2 CH(CH 3 )2

Compound B is heated with water (11) on a steam bath for 8 hours until conversion to 1-hydroxy-l-methylethylphosphonous acid is complete (monitored by 31 P nmr). The water is removed on a rotary evaporator and the residue is completely dried by co-evaporation

with toluene. A sample of this phosphonous acid (4.6g, 0.037M), isobutyl alcohol (3.02g, 0.041M) and dimethylaminopyridine (0.5g, 0.0041M) is stirred at 5°C in tetrahydrofuran. Dicyclohexylcarbodi-mide (8.4g, 0.041M) is added portionwise over 30 minutes. On completion of the reaction ( 31 P nmr), ether (50ml) is added and the precipitated diccylohexyl urea is filtered off. Evaporation of the ether liquors gives a pale yellow oil (6.7g) which is purified by chromatography on silica using ether, then ethyl acetate, as eluant to give Compound D, isobutyl (l-hydroxy-l-methyle-hyl)phosphinate.

Found: C 47.0, H 9.5, P 17.1%; C 7 H 17 O 3 P requires C 46.7, H 9.5, PI7.2%.

31 P nmr (CDC1 3 , 162 MHZ) δ = 42.2 ppm.

Compound E

(CH 3 CH2θ)2 P CH 2

OCH2CH 3

To a solution of diisopropylamine (15.7ml, 0.112 mol) in teσahydrofuran (200ml) at -20°C, n-butyllithium (1.6M in hexanes, 75.4ml) is added dropwise. The solution is allowed to warm to 0°C and cooled to -74°C after 15 minutes. Ethyl (1,1-diethoxyethyl) methylphosphinate prepared as described in EP 0 009 348 (25.0g, 0.112 mmol) is added dropwise by syringe over 5 minutes, maintaining the temperature at below -57°C. After 1 hour at -70°C, diethyl chlorophosphate (17.3ml, 0.119 mol) is added dropwise and, after a further hour, lithium diisopropylamide (0.112mol) (prepared by the addition of n butyllithium to diisopropylamine as above) in THF (75ml) is added over 20 minutes at -65°C. The reaction mixture is stirred for a further hour at -70°C, then warmed to 20°C, and stood for 18 hours. Saturated aqueous ammonium chloride (20ml) is added, and the reaction mixture is concentrated at below 35°C. Dichloromethane is added to the residue, which is then washed with water three times. The water layer is back-washed with ether. The combined organic phases are dried with a brine wash, then over magnesium sulphate, and evaporated to a brown oil.

The crude product is purified by short path distillation to give an intermediate product as clear viscous oil.

30 -

b.p. 165-175°C (0.005mmHg)

31 P nmr (CDC1 3 , 161MHZ) : 39.35 (d, Jpp 15.6 Hz), 21.30 (d) mass spectrum CI. (NH 3 ) 378 (MNH 4 + ), 117 (100)

The intermediate product is of formula

o o CH 3

(CH 3 CH 2 0)2 • CH 2 (OCH 2 CH 3 )2

OCH 2 CH 3

To a solution of the intermediate product (4.5g, 12.5mmol) in chloroform (10ml), chlorotrimethylsilane (5ml) is added dropwise over 5 minutes. The solution is stirred for 4 hours then ethanol (2ml) is added. After a further 1.5 hours, the solvent is evaporated and the residue distilled by short path distillation (160°C/0.02mmHg) Compound E is obtained as a clear oil.

31 P nmr (CDC1 3 , 161MHZ) 26.47 (d, Jpp, 5.4Hz) 18.95 (d, Jpp, 5.9Hz) ppm J PH 579Hz mass spectrum C.I.(NH 3 ) 262 (MNH 4 + )

Compound F

To a solution of Compound C (1.50g, 3.53 mmol) in THF 00ml) at 20°C, tetrabutylammonium fluoride (1.0M in THF, 3.89ml) is added When the reaction is complete, the solvent is evaporated and the residue purified by chromatography on silica gel, eluting with a hexane/ether gradient The product is distilled (short path) (125-130°C, 0.02 mmHg) to give further purified material.

! H nmr (CDC1 3 , 400 MHz) 5.86 (d, 1H, J=3.7Hz); 5.47 (s, 1H); 5.18 (s, 1H); 4.90 (d. 1H, J=2.5Hz); 4.81 (m, 1H); 3.87 (dJH, J=12Hz); 3.67 (dd, J=4.4, 11.9 Hz, 1H); 1.26 (s, 3H); 1.19 (s, 3H) ppm.

Compound G

H 2 C U CH 3

To a suspension of methyltriphenylphosphonium bromide (82.5g, 0.231 mol) in dry tetrahydrofuran (500ml) at -70°C under argon is added n-butyl lithium (1.6m in hexane, 144ml, 0.23 lmol) over about 10 minutes. The mixture is allowed to warm to 15°C during which time an orange solution forms. This mixture is re-cooled to -70°C, more n-butyl lithium (6ml) is added, and after a further 15 minutes, a solution of

5-O-benzoyl-l,2-di-O-acetonide-3-ketoxylose prepared as described by H.S. Mosher. J. Org. Chem. 1986, 51, 2702 (50.0g, 0.171mol) in dry tetrahydrofuran (100ml) is added in 5 batches over 35 minutes, whilst maintaining the reaction temperature at -66 to -70°C. The mixture is kept at -70°C for 2 hours, then allowed to warm to +10°C over 1.5 hours and maintained at this temperature for 3 hours. Acetic acid (3.5ml) is added, followed by hexane (500ml). The resultant precipitate is separated by filtration and the liquors passed through a pad of silica gel (ca 2cm deep). This pad is washed with ether (1 litre) and the filtrate is evaporated to yield a crude oil. The product is purified by flash column chromatography over silica gel (Merck, Art 15111, 10cm 0, 5cm L) eluting with hexane then hexane: ether (3:1) mixtures to yield Compound G as a colourless solid, mp 61-62°C. δH (CDC1 3 ) 8.10 (2H, d, Ph-H), 7.55 (IH, t, Ph-H), 7.41 (2H, t, Ph-H), 5.95 (IH, d, H-l), 5.50) (IH, s, C=CH), 5.35 (IH, s, C=CH), 5.10 (IH, m, H=4), 4.96 (IH, d, H-2), 4.55 (IH, dd, H-5), 4.40 (IH. dd, H-5), 1.55 (3H, s, CH 3 ), 1.40 (3H, s, CH 3 ) ppm.

δC (CDC1 3 ) 166.2 (COPh), 145.6, 133.1, 129.6, 128.3, 112.7, 112.6, 104.5, 81.6, 77.3, 65.6, 27.3, 27.0 ppm.

Found: C 66.5, H 6.4%; C 16 H 18 O 5 requires C 66.25, H 6.25%.

Compound H

A mixture of Compound G (20.0g, 68.9 mmol) in water (20ml) and tetrahydrofuran (150ml) and

DOWEX ® 50W x 2 50-100 mesh ion-exchange resin (100ml) is heated at reflux for 5 days. The mixture is filtered and the resin washed with dichloromethane (100ml). The filtrates are evaporated and co-evaporated with toluene (3 x 100ml) to yield a viscous orange oil. To a solution of this oil in dichloromethane (100ml) at 0°C is added pyridinc (22ml, 0.276mol) and acetic anhydride (19.3ml. 0.207mol) and the mixture is stirred at 0°C for 3 hours. The solvents are evaporated to yield the crude product which is purified by column chromatography over silica gel (Merck, Art 7734, 500g) eluting with ether hexane (1:10 to 4:10) mixtures. Fractions adjudged pure by thin layer chromatography are collected and evaporated to yield Compound H as a colourless oil, as a mixture 5:2 of α:β anomers at position 1.

Compound I

A suspension of thymine (4.38g, 34.7 mmol) and bis(trime-hylsilyl)acetamide (14.12g, 69.4 mmol) is heated to 70°C with stirring under argon for 2 hours. The resulting solution is allowed to cool to 22°C over 2 hours. A solution of Compound H (11.6g, 34.7 mmol) in 1,2-dichloroethane (15ml) is added to the above reaction mixture with stirring at 22°C. Trimethylsilyl trifluoromethane sulphonate (9.25g, 41.6mmol) is then added, dropwise, over 15 minutes. The reaction mixture is heated to 50°C, with stirring, for 3 hours. A solution of saturated aqueous sodium hydrogen carbonate (80 I) is added slowly to the mixture and, when effervescence ceases, this is transferred to a separating funnel. The products are extracted into chloroform (4 x 50 ml) and the extracts washed with brine before drying (magnesium sulphate). Evaporation affords the crude product 05.0g). Purification by flash column chromatography over silica gel (Merck, An 15111, 4cm x 10 cm L) eluting with hexane, then hexane:ethyl acetate (1:1) mixtures, affords after evaporation of those appropriate fractions ajudged pure by thin layer chromotagraphy, Compound I as a colourless glassy solid mpt. 55-58°C.

J H NMR (CDCI 3 ) δ 8.95 OH, bs, NH), 8.04 (2H, m, Ph-H). 7.61 (IH, m, Ph-H), 7.48 (2H, m, Ph-H), 7.17 (IH, d, J=1.3H thymine-H), 6.07 (IH, d, J=5.7Hz, H-l), 5.74 (IH, , H-2'), 5.49 (IH, m, C=CH), 5.41 (IH, m, C=CH), 5.03 (IH, , H-4 , 4.71 (IH, dd, J=12.3, 2.8 Hz, H-5 , 4.54 (IH,

dd, J=12.3, 4.4Hz, H-5'), 2.15 (3H, s. COCH 3 ), 1.65 (3H, d, J=1.0 Hz CH 3 ) ppm.

13 C NMR (CDC1 3 ) δ 170.29 (CH 3 C(O)), 166.04 (PhC(O)), 163.65 (C-2) 150.62 (C-4), 141.70 (C-3 1 ), 134.56 (C-6), 133.46, 129.43, 129.28, 128.60, (Ph), 112.76 C- ^ Ctiy , 111.85 (C-5), 86.72 (C-l 1 ), 78.20 (C-2 1 ), 75.32 (C-4 1 ), 65.42 (C-5 1 ), 20.65 (CH 3 C(O)), 12.15 (CH 3 )ppm.

Found: C 59.6, H 5.25, N 6.7%; C 20 H 20 N 2 O 7 requires C 60.0, H 5.03, N 7.00%.

Compound J

O CH,

(OCH 2 CH 3 ) 2

CH 3

To a solution of methyl(l,l-diethoxyethyl)phosphine oxide, prepared as described in EP 0 501 702 (89.3g, 0.5mol) in THF (900ml) at -78°C under an atmosphere of argon is added a solution of potassium bis(trimethylsilyl)amide (688ml, 0.521 mol) in toluene over 15 minutes. After stirring for 1 hour at -78°C, methyl iodide (34ml, 0.55mol) is added over 5 minutes and stirring at -78°C continued for 1 hour. The reaction is then quenched by the addition of a 1% solution of NaH 2 PO 4 (450ml) and slow warming to room temperature. Concentration gives an aqueous suspension to which dichloromethane (600ml) is added. The organic phase is separated and washed with 1% NaH 2 PO 4 (500ml), followed by water (500ml). Drying over MgSO 4 , concentration and purification by flash vacuum silica column chromatography (chloroform-ethanol 40:1) gives a clear oil which is distilled to give dimethyl (l,l-diethoxyethyl)phosphine oxide, b.p. 100°C at 0.05mmHg.

Found C 49.1, H 10.2, P 16.1%; C 8 H 19 O 3 P requires C 49.5, H 9.85, P 15.95%.

31 Pnmr l H decoupled (CDC1 3 , 36 MHz) δ 48.3 ppm.

Compound K

OSi(CH 3 )3

This is prepared as described in R. G. HALL et al. Tetrahedron 1989, 45, p3787.

Compound L

This aldehyde is available commercially.

Compound M

A solution of isobutyl(l -hydroxy- l-methylethyl)phosphinate (12.6g, 0.07M) and ten-butylcyclohexylperdicarbonate (0.5g) in toluene (2ml) is heated at 80°C under argon. The compound of formula

(19.34g, 0.07M) in toluene (2ml) is added portionwise over 2 hours. A further 2.5g perdicarboπate in toluene (6ml) is added over 2 hours. The reaction mixture is stirred for a further 10 hours, adding perdicarbonate (0.25g) every 2 hours when the reaction appears complete ( 31 P nmr). The mixture is cooled and evaporated to a gum which is purified on silica by flash chromatography using ethyl acetate, then 5% methanol in ethyl acetate, as eluants. The methanolic eluates were re-chromatographed on silica using 5% methanol in ethyl acetate as eluant to give Compound M.

31 P nmr (CDC1 3 162 MHz) δ = 56.0, 56.2 ppm.

Compound N

phenyl

To a solution of aqueous ammonia (20ml, 20%), Compound M (0.95g, 2.1mmol) is added. The mixture is heated at 70°C for 12 hours, cooled, evaporated and then co-evaporated with toluene. The residue is dissolved in dichloromethane (9ml). To the resulting solution at -10°C is added triethylamine (0.32ml, 2.3mmol), followed dropwise by isobutyl chloroformate (0.55ml, 4.2mmol). After 45 minutes the reaction mixture is allowed to warm to 20°C. After 2 hours, the reaction mixture is evaporated and the residue purified by chromatography on silica gel, eluting with a gradient of methanol/ethyl acetate. The product, a mixture of two diastereoisomers, is obtained as a clear oil.

31 P nmr (36MHz, CDC1 3 ) δ 38.8, 39.1 ppm; J PH 540 Hz. m/z C1(NH 3 )399(MH + ), 416(MNH 4 + ), 341 (100) (M-iBu).

36 -

Compound O

A mixture of the compound of formula

(65g, 0.155M) and sodium iodide (94g, 0.62M) in butan-2-one (1.51) is heated to reflux for 5 hours. A further 10% of sodium iodide is added and heating continued for 3 hours. The solvent is removed and the dark brown residue is partitioned between chloroform and water. Sodium thiosulphate is added portionwise until the solution is colourless. The chloroform extracts are separated, washed with sodium bicarbonate then brine and dried (MgSO 4 ). Evaporation gives a pale yellow oil which is purified by chromatography on silica using hexane: ethyl acetate, 2:1, eluant, to give Compound 16. An analytical sample is obtained by bulb to bulb distillation (100°C/0.1mm Hg), [αlp 25 + 107.5, c 1.13 CHC1 3 ; Found C 58.0, H 7.0; C n H 16 O 5 requires C 57.9, H 7.1%.

Compound P

Compound O (15g 0.066M) dissolved in methanol (100ml) is added to a solution of potassium carbonate (22.7g, 0.165M) in water (100ml). After 15 minutes the reaction is complete (TLC).

The solvent volume is reduced to 50ml and after further co-evaporation with water the residue is washed with chloroform (3 x 100ml). The chloroform extracts are washed with brine then dried (MgSO 4 ). Evaporation gives a white solid, m.pt. 67-5-68°C, [a^+SH.lfc. 0.95 CHC1 3 . Found C57.8, H8.0; Calculated for G^O^ C58.05. H7.6%.

Compound Q

is prepared as described by Hall, Hough and Pritchard, J. Chem. Soc. 1961, 1541.

Compound R

To a solution of ethyl(l,l-diethoxyethyl)phosphinate (1.55g, 6.9mmole) in THF (30ml) at -78°C under an atmosphere of argon is added n-butyllithium (4.3ml, 1.6 molar solution in hexanes) slowly over 5 minutes. The resulting solution is stirred at -78°C for 1 hour. Boron trifluoridc etherate (0.85ml, 6.9mmole) is then added over 2 minutes followed by the dropwise addition of a solution of an oxetane of formula

prepared by the method of: J.P. Horwitz et al J. Org. Chem. 28, 942, (1963) (0.40g, 2.3mmole) in THF (10ml). The resulting solution is stirred for 2 hours at -78°C before the addition of NaHCO 3 (saturated, 5ml). The resulting mixture is allowed to warm to ambient temperature over 1 hour and is then concentrated in vacuo. Addition of dichloromethane and filtration gives a clear oil after concentration. Purification by flash silica column chromatography (chloroform-ethanol 40:1) gives Compound R as a thick oil.

Found: C 50.6%, H 8.4%, P 7.7%; C H 33 O 8 P.i H 2 O requires C 50.35%, H 8.45%, P 7.65%.

3lD P n„ m m,r- 1 Η decoupled (CDC1 3 , 36.4MHz) δ 51.3, 51.1 ppm.

Compounds S and T

Compound S

Compound T

A solution of dimethylsulphoxide (0.56ml, 7.9mmol) in dichloromethane (5ml) is added to a mixture of oxalyl chloride (0.3ml, 3.4mmol) in dichloromethane (45ml) maintained at -70°C. After 10 minutes, a solution of Compound R (1.05g, 2.64 mmol) in tetrahydrofuran 00ml) is added dropwise. maintaining the temperature at -70°C. After 15 minutes, triethylamine (2.76ml,

0.0198mol) is added dropwise and the mixture is allowed to warm gradually to ambient temperature. The mixture is diluted with ethyl acetate (150ml) and washed with water (2 x 50ml). Evaporation of the organic phase and co-evaporation with more ethyl acetate gives a mixture of Compounds S and T as a colourless oil which is pure enough for use in subsequent reactions. A sample (80mg) is purified by column chromatography over silica gel (Merck, Art 7734, 3g) eluting with dichloromethane: ethyl acetate (25:1) mixtures. Pure fractions are evaporated to give a mixture of Compounds S and T as a colourless oil. v max (thin film) 3600-3100 (br, OH), 1780, 1740 (CO) cm 1 31 P nmr (CDC1 3 ) δ 52.01, 51.72 and 48.30, 48.01 ppm.

Compound U

To a solution of the mixture of Compounds S and T (1.02g, 2.485mmol) in ethanol (50ml) at - 10°C is added sodium borohydride (113mg, 2.98mmol) in three portions over 15 minutes. The mixture is partitioned between ethyl acetate (200ml) and water (50ml). The organic phase is washed with water (2 x 50ml), dried (MgSO4), filtered and evaporated to yield Compound U as a colourless oil.

31 P (CDC1 3 ) δ 49.32 ppm.

l nmr (CDC1 3 ) δ 5.76 (IH, d, H-l), 4.58 (IH, m, H-2 1 ), 4.2 (2H, m, H-3, H-4), 3.7 (6H, m, OCH 2 x 3), 3.05 (IH, br d, OH), 2.15 - 1.7 (4H, m, PCH,CH,), 1.58 and 1.35 (2 x s, 2 x OC(CH 3 ) 2 ), 1.44 (3H, d, PCCH 3 ), 1.35 and 1.25 (6H, 2 x t, OCH ? CH,), 1.20 (6H, t, P COCH ? CH, x 2)ppm.

Compound V

To a solution of Compound U (0.97g, 2.447mmol) in chloroform (35ml) containing 0.6% ethanol at room temperature, under argon is added trimethylsilyl chloride dropwise over 30 minutes. The mixture is stirred at 24°C for 6 hours, then kept at -20°C for 18 hours. Evaporation gives crude product (780mg) as a colourless oil. Purification by column chromatography over silica gel (Merck, An 7734, 35g) eluting with 1-8% ethanol: chloroform mixtures. Appropriate fractions are collected and evaporated to give Compound V as a colourless oil.

31 P nmr (CDC1 3 ) δ 38.90 and 38.64 ppm.

*H nmr (CDC1 3 ) δ 7.80 (0.5H, m, P-H), 6.43 (0.5H, m, P-H), 5.75 (IH, m, H-l), 4.48 (IH, m, H-4), 4.15 (IH, m, POCH).4.08 (IH, m, POCH). 3.61 (IH, m, H-3), 2.1-1.8 (4H, m, P CH ? CH ? ), 1.55 (3H, s, CCH 3 ), 1.35 (6H, m, CCH 3 and POCH^CH,) ppm.

13 C nmr (CDC1 3 ) 112.47 (s), 103.54 (s), 79.30 (d), 78.54 (s), 75.29 (s), 62.36 (s), 26.38 (s), 26.28 (s), 24.71 (d), 16.210 (s) ppm.

Compound W

(CH 3 )3C l

To a solution of an aldehyde of formula XXIII where R 5 , is hydrogen, R 6 is 1-thyminyl and R 7 is ten-butyl diphenylsilyl, prepared as described in WO 92/20823, 01-2g 23 mmol) in anhydrous ethanol (120ml) at room temperature is added NaBH 4 (865mg, 23 mmol) portionwise over 5 minutes. After 1 hour, the reaction mixture is quenched with water, diluted with ethylacetate (500ml) and washed with water (2 x 50ml). After back extration of the aqueous phase, the combined organic phase is dried (MgSO 4 ) and concentrated to give Compound W as a white

solid

l nmr (CDC1 3 , 400MHz) δ 9.10 (IH, s, NH) 7.65 (4H, d, Ar 4 x CH ortho), 7.40 (7H, M, Ar 4 x CH meta, 2 x CH para + H6) 6.13 (IH, t, HI') 4.00 (IH, dd, H5'), 3.93 (IH, m, H4') 3.82 (IH, dd, H5'), 3.62 (2H, m, CH ? OH) 2.60 (IH, m, H3'), 2.32 (IH, m, H2'), 2.12 (IH, m, H2') 1.62 (3H, s, T-CH,) and 1.10 (9H, s, Ηu) ppm.

Compound X

Ph = phenyl T = 1-thyminyl

To a solution of Compound W (9g, lδ.lmmol) in dry DMF (100ml) at 0-5°C is added 2,6-lutidine (4.25ml, 36.5mmol) followed by methyltriphenoxyphosphonium iodide (9.45g 20.9 mmol). The resulting mixture is allowed to warm to room temperature. After 1 hour the mixture is diluted (200ml ethyl acetate) and washed with 0.1N NaS 2 O 3 (2 x 20ml), 0.5N Hydrochloric acid (2 x 20ml) and water (2 x 20ml). Drying, concentration and purification by flash silica column chromatography (gradient elution chloroform: ethylacetate 20:1 - 7:1) gives Compound X as a white solid.

l H nmr (CDC1 3 , 400 MHz) δlθ.2 (IH, s, NH) 7.66 (4H, d, 4 x CH ortho), 7.40 (7H, , 4 x CH meta, 2 x CH para + H6) 6.19 (IH, t, HI') 4.02 (IH, dd, US') 3.82 (IH, m, H4'), 3.78 (IH, dd, HS'), 3.17 (IH, dd, CH 2 D. 3.10 (IH, dd, CH ? I), 2.68 (IH, m. H3'), 2.30 (IH, m, ) 2.23 (IH, m, H2') 1.66 (3H, s, CH 3 -T), 1.10 (9H, s, tBu) ppm.

Example 1

Compound 1

A solution of Compound A (6.39g, 24.9mmol) and biscyclohexyl perdicarbonate (BCHPC) (0.99g, 2.5mmol) in toluene (2ml) is added dropwise to stirred Compound B (5.16g, 37.4 mmol) at 80°C under an argon atmosphere. After 4 hours, the reaction mixture is cooled, evaporated and purified by chromatography on silica gel, eluting with ethanol chloroform, to give the product, Compound 1, a solid m.p. 95 - 100°C, as a mixture of two epimers at phosphorus.

31 P nmr (CDC1 3 , 24MHz) δ 56.5, 56.3 ppm.

Elemental Analysis expected: C51.77%, H 7.92%, P 7.86%

Found: C 51.33%, H 7.79%, P 7.92%.

Recrystallisation of the above product from ether/hexane gives a single diastereomer (d.e. 96%) 31 P nmr (CDC1 3 , 24MKz) δ 59.9 ppm.

Example 2

Compound 2

A solution of Compound 1 (0.50g, 1.3mmol) in methanol (10ml) and aqueous ammonia (30%, 5ml) is heated to 80°C and additional quantities of aqueous ammonia are added (x 1 ml until the reaction is complete (60 hours). The reaction mixture is evaporated, triturated with ether and crystallised to give Compound 2.

31 P nmr (D 2 O, 24MHz) δ 23.3ppm.

Elemental Analysis: expected C44.8%, H7.8%, N4.0%, P8.9% C 13 H 26 NO 7 P.0.5H 2 O: Found C44.7%, H7.9%, N3.6%, P9.0%

Example 3

Compound 3

To a solution of Compound 2 (80mg, 0.25mmol) in dichloromethane (2ml) at 0°C, ethyl chloroformate (28μl, 0.30 mmol) and triethylamine (39μl, 0.27mmol) are added. After 2.5 hours, the reaction mixture is diluted with dichloromethane, washed successively with water and brine and then evaporated. The residue is purified by chromatography (silica gel; eluting with 5% e-hanol chloroform) to give Compound 3 as a mixture of two diastereoisomers.

31 P nmr (CDC1 3 , 24MHz) δ 34.56, 35.17 ppm

] H nmr (CDC1 3 , 400MHz) δ 6.56 (m, -H), 7.92 (m, _H, J PH 537Hz) ppm.

Example 4

Compound 4

To a solution of Compound 2 (274mg, O.δlmmol) in dichloromethane at 0°C, isobutvlchloroformate (0.13ml, l.Ommol) and triethylamine (0.13ml, 0.94mmol) is added. After 6.5 hours the mixture is evaporated and then purified by silica gel chromatography, eluting with 2% EtOH/CHC-3, to give Compound 4 as a mixture of two diastereoisomers.

31 P nmr (CDC1 3 . 24MHz) δ 36.9, 36.2 ppm, J PH 540 Hz.

l H nmr (CDC1 3 , 400MHz) δ 6.53 (m, .H), 7.90 (m, _H, P-H) ppm.

Example 5

Ph

Compound 5 (Ph = phenyl)

To isobutyl methylphosphinate (0.95g, 6.98 mmol) at 80°C under argon, is added over 2.5 hours a solution of Compound C (l.OOg, 2.35 mmol) and BCHPC (O.lg, 0.25 mmol) in toluene (1.5ml). After a further 1 hour the reaction mixture is cooled and solvent and excess reagents removed by short-path distillation (70-80°C, 0.05mmHg). The residue is purified by chromatography on silica gel, eluting with hexane/ethyl acetate, 50:50 - 0:100). The product, Compound 5, a viscous oil is obtained as a mixture of two diastereomers.

31 P nmr (CDC1 3 , 24MHz) δ 52.9, 52.3ppm.

Example 6

Compound 6

(Ph « phenyl)

A solution of Compound C (ll-5g, 27.1mmol) and BCHPC (0.5g, 1.3mmol) in toluene (15ml) is

added to stirred Compound D (5.9g, 32.5mmol) under argon at 75°C over 50 minutes. After 100 minutes, further BCHPC (O.lg) is added. After 3 hours, the reaction mixture is cooled, diluted with ethyl acetate and washed with water then brine. The organic phase is dried over magnesium sulphate, evaporated, and the residue purified by silica gel chromatography, eluting with a hexane/ethyl acetate gradient and then a methanol ethyl acetate gradient. Compound 6 is obtained as a mixture of two diastereomers, plus separated isomers.

31 P nmr (CDC1 3 , 24MHz) δ 54.0 ppm ISOMER A l H nmr (CDC1 3 , 400MHz) δ 4.84 (t, IH) ppm

31 P nmr (CDC1 3 , 24MHz) δ 54.1 ppm ISOMER B l H nmr (CDC1 3 , 400MHz) δ 4.92 (t, IH) ppm

Elemental Analysis Expected: C63.55%, H8.17%, P5.12%, Si4.64%

C 32 H 51 O 7 PSi Found: C63.1%, H8.1%, P5.2%, Si5.0% mass spectrum C.I.(NH 3 ) 605 (MH*)

Example 7

Compound 7 (Ph = phenyl) CH^OH

A solution of Compound C (0.50g, l.lδmmol) and BCHPC (47mg, 0.12mmol) in toluene (0.5ml) is added to stirred Compound B (0.325g, 2.36mmol) under argon at 80°C over 30 minutes. After 2.5 hours, BCHPC (47mg) is added After 5 hours (total), the reaction mixture is cooled, evaporated under vacuum and the residue purified by chromatography on silica gel, eluting with 2-5% EtOH/CHCl 3 to give the product as a mixture of two diastereomers.

31 P nmr (CDC1 3 , 24MHz) δ 56.3, 56.1 ppm

The isomers can be separated by chromatography with ethyl acetate as eluent:

31 P nmr (CDC1 3 , 24MHz) δ 57.1 ppm

l H nmr (CDC1 3 , 400MHz) δ 4.80 (t, Hz, J 4.0H2) ppm

31 P nmr (CDC1 3 , 24MHz) δ 57.0 ppm

l H nmr (CDC1 3 , 400MHz) δ 4.92 (t, H2, J 4.0Hz) ppm

Example 8

Ph

A solution of Compound C (2.90g, 6.83 mmol) and BCHPC (0.27g, 0.68mmol) in toluene (3ml) is added to stirred Compound E (2.00g, 8.19mmol) under argon at 80°C over 30 minutes. After 4 hours, the reaction mixture was cooled and purified by silica gel chromatography, eluting with 0-5% ethanol in ethyl acetate, to give Compound 8 as a mixture of two diastereoisomers.

31 P nmr (CDC1 3 , 24MHz) δ 45.81, 45.56, 45.35, 45.12, 20.04, 19.80 ppm

Elemental Analysis expected: C55.24%, H7.70%, P8.9% C 32 H 50 O 9 P 2 Si.l.5H 2 O found: C55.5%, H7.7%, P7.6%

Example 9

Compound 9

A solution of Compound F (0.55g, 3.0mmol) and BCHPC (0.24g, O.όmmol) in toluene (lml) is added dropwise to stirred Compound B (0.82g, ό.Ommol) at 80°C, under argon. After 4.5 hours, the reaction mixture is evaporated and subject to short path distillation to remove excess Compound B (80-100°C, 0.003 mmHg). The residue is chromatographically purified on silica gel, eluting with 5% EtOH in chloroform, to give Compound 9, an oil, as a mixture of his diastereomers.

31 P nmr (CDC1 3 , 24 MHz) δ 58.0, 57.6ppm

Elemental Analysis Expected: C 43.337c, H 8.11%, P 8.60% Found: C43.6%, H 8.1%, P8.9%

Example 10

Compound 10 (Ph = phenyl)

A solution of Compound 7 ( .lg, 2.8mmol) and 1,8 diazabicyclo[5.4.0]undec-7-ene (DBU) (0.63 ml, 42mmol) in methanol 05.3ml) is heated to 70°C. After 6 hours, the reaction mixture is cooled and evaporated to give a mixture of Compound 10 as a DBU salt and excess DBU.

31 P nmr (CDC1 3 , 161MHz) δ 22.2 ppm

Example 11

Compound II (Ph = phenyl)

OCH 2 CH(CH 3 >2

A solution of crude Compound 10 as obtained in Example 10 (12.0g, 14.5mmol) in dichloromethane 020ml) is cooled to -10°C and isobutyl chloroformate (2.65ml, 20.3mmol) is added dropwise over ten minutes. After 30 minutes, additional chloroformate (3.79ml, 29.0mmol) and triethylamine (4.04ml, 29.0mmol) are added dropwise at less than -10°C. The reaction mixture is allowed to warm to 20°C. After 3.5 hours, the mixture is evaporated, diluted with ethyl acetate and washed with water. The organic phase is dried over magnesium sulphate, evaporated, and purified by silica gel chromatography, eluting with ether then an ethanol/ethyl acetate gradient. Compound 11, a solid, is obtained as a mixture of two diastereomers.

31 P nmr (CDC1 3 , 24MHz) δ 36.4, 35.8ppm

! H nmr (CDC1 3 , 400MHz) δ 7.20 ppm (br.s., IH, J PH 540 Hz) ppm mass spectrum C.I.(NH 3 ) 547 (MH + ), 564 (MNH 4 + )

Example 12

Compound 1 (Ph -- phenyl)

C(CH 3 ) 2 OSi(CH 3 ) 2 C(CH3) 3

To a solution of tertbutyldimethylsilylchloride (0.77g, 5.1mmol), triethylamine (0.71ml, 5.1mmol) and Compound 7 (2.6g, 4.6mmol) in dichloromethane (6ml) at 0°C, 4-dimethylaminopyridine (62mg, 0.51mmol) is added. The mixture is allowed to warm to 20°C immediately and stood at 20°C for 18 hours. The solvent is evaporated and the residue purified by silica gel chromatography, eluting with an ether/hexane gradient, to give Compound 12 as a mixture of two diastereoisomers.

31 P nmr (CDC1 3 , 24MHz) 656.16, 56.37ppm

! H nmr (CDC1 3 , 400MHz) δθ.90 (s, Ηu), 0.70 and 0.73 (2 x s, < Bu), 0.00 (2 x s, 3H), -0.03 (2 x s, 3H) ppm

Example 13

C(CH 3 ) 2 OSi(CH 3 )2C(CH 3 > 3

To a solution of Compound 6 (2.2g, 3.6mmol) and triethylamine (0.66ml, 4.7mmol) in dichloromethane 00 ml) at 0°C, tertbutyldimethylsilylchloride (0.66g, 4.35mmol) is added dropwise, followed by 4-dimethylaminopyridine (40mg, 0.36 mmol). The reaction mixture is allowed to warm to 20°C and stirred for 45 hours, whereupon further quantities of the silyl chloride (0.27g) and triethylamine (0.28ml) are added. After a further 3.5 hours, the reaction mixture is evaporated, diluted with ether and filtered through 'Hyflo' and finally evaporated. The residue is purified by dry flash chromatography on silica gel, eluting with hexane/ ethylacetate (1:1 - 0:1) to give Compound 13.

31 P nmr (CDC1 3 , 24MHz) δ 54.2 ppm

J H nmr (CDC- 3 , 400MHz) δ 0.0 (s, 6H), 0.80 (s, 9H), 0.95 (s.9H) ppm.

Example 14

Compound 14 (Ph = phenyl)

C(CH 3 ) 2 OH

A solution of Compound G (12.18g, 41.96 mmol) and BCHPC (1.25g, 3.1 mmol) in toluene 09ml) is added dropwise over 35 minutes to Compound D (8.17g, 45.3 mmol) under argon at 80°C. After 75 minutes, further BCHPC (0.30g) is added. After a further 90 minutes, the reaction mixture is cooled, evaporated and dissolved in boiling ethyl acetate 05ml). Hexane is added until the solution becomes cloudy. The solid which precepitates upon cooling is collected and washed with cold ether. The filtrate is partially evaporated and ether is added, whereupon further solid is precipitated and filtered off. The filtrate is evaporated and the resulting residue purified by dry flash chromatography on silica gel, eluting successively with ether and an ethanol ethyl acetate gradient (0-5%) to give Compound 14 as a mixture of two ribo isomers and two xylo isomers, the former the major product.

31 P nmr (CDC1 3 , 24MHz) 54.17 (xylo); 53.81 (ribo) ppm

The solid precipitated during the purification procedure is a mixture of two ribo isomers of the product, enriched significantly in one isomer (25:4):

H nmr (CDC1 3 , 400MHz) δ 4.86 (t, IH) major isomer; 4.93 (t, H) minor isomer ppm.

Example 15

PhCOO

Compound 15 (Ph = pnenyl)

C(CH 3 >2θH

A solunon of Compound G (5.00g, 17.2mmol) and BCHPC (0.69g, 1.7 mmol) in toluene (5ml) is added dropwise over 1.25 hours to Compound B (2.85g, 20.7mmol) at 80°C under argon. After 3.75 hours, the reaction mixture is cooled, evaporated and the residue purified by chromatography on silica gel, eluting with an ethanol/ethyl acetate gradient. Compound 15 is obtained as a mixture of two ribo and two xylo-isomers in a 10:1 ratio. The product is recrystallised from hexane/ethyl acetate to remove the minor xylo isomers.

31 P nmr (CDC1 3 , 24MHz) δ 56.25, 55.96, 55.79 (ribo), 55.70 (ribo) ppm Elemental analysis expected: C56.07%, H6.82%, P7.23% C 20 H 29 O S P found: C55.6%, H7.2%, P7.6% mass spectrum CI. (NH 3 ) 429 (MH + )

Fuπher recrystallisation gives one isomer (Isomer A) pure (98%).

31 P nmr (CDC1 3 , 161MHz) 656.27 ppm

>H nmr (CDC1 3 , 400MHz) δ 4.83 (t, IH) ppm

Recrystallisation of the residue from ether/hexane gives the other isomer Osomer B)

! H nmr (CDC1 3 , 400MHz) δ 4.89 (t, IH) ppm

M/Z CI (NH 3 ) 429 MH +

The two xylo isomers are separated from the ribo isomers by HPLC.

! H nmr (CDC1 3 , 400 MHz) 65.00 (d, J=3.6Hz, IH); 5.09 (d, IH) ppm

Example 16

Compound 16

(Ph = phenyl)

CH 3 C (00.20.3)2

A solution of Compound G (4.13g, 14.2mmol) and BCHPC (0.57 g, 1.42mmol) in toluene (4ml) is added dropwise over 10 minutes to ethyl (ϋ-diethoxyethyl)phosphinate (4.49g, 21.3mmol) under argon at 75°C. Additional quantities of BCHPC (0.2g) are added every hour. After 6 hours, the temperature is raised to 90°C, for 3 hours. The reaction mixture is cooled and purified by chromatography on silica gel, eluting with a hexane/ethyl acetate gradient. Excess phosphinate reactant is distilled out of the product using a short path apparatus (90°C 0.2mmHg). The product. Compound 16 as a mixture of two major isomers, is further purified by chromatography, as above.

31 P nmr (CDC1 3 , 24MHz) 646.97, 46.63 ppm

Example I *

Compound 17 (Ph * phenyl)

CH(OCH 2 CH 3 )2

A solution of Compound G (0.94g, 3.2mmol) and BCHPC (0.13g, 0.32mmol) in toluene 0ml) is added dropwise to ethyl (diethoxymethyl)phosphinate (0.95g, 4.86mmol) under argon at 75°C. When the reaction is complete (TLC), the reaction mixture is cooled and purified by silica gel

chromatography, eluting with an ethanol/ethylacetate gradient. The product, Compound 17 as a mixture of two isomers, is further purified by removing ethyl(diethoxymethyl)phosphinate by shoπ path distillation (110°C/O.02 mmHg).

31 P nmr (CDC1 3 , 24MHz) δ 43.65 ppm

Elemental analysis expected: C52.87%, H 7.56%, P 5.90% Cz . H 35 O 9 P.2H2O Found: C52.9%, H 7.2%, P 5.9% M/Z CI (NH 3 ) 487 MH *

Example 18

To a solution of Compound 16 (1.79g, 3.6mmol) in chloroform (14ml) and ethanol (3.6ml) at 0°C, chloromethylsilane (0.50ml, 3.9mmol) is added. The reaction solution is stood at 10°C for 64 hours and then at 20°C for 4 hours. The solvent is evaporated and the residue purified by chromatography on silica gel. The product, Compound 18 as a mixture of two isomers, is diluted by a gradient of 0-20% e-hanol in ethyl acetate.

31 P nmr (CDC1 3 , 24MHz) 6 34.34, 34.27 ppm J PH 557 Hz.

! H nmr (CDC1 3 , 400MHz. δ 7.22 (d, IH, J PH 550Hz), 5.89 (t, IH) ppm

Example 19

Compound 19 (Ph = phenyl)

A solution of Compound 15 (6.70g, 15.6mn.oI) in methanol (20ml) and aqueous ammonia (33%, 20ml) is stirred at 20°C for 1 hour then tetrahydrofuran (10ml) is added. After 48 hours, the solution is evaporated, and the residue dissolved in water and extracted with chloroform until the product is fully extracted. The combined organic phase is evaporated and co-evaporated, to give Compound 19.

31 P nmr (D20, 24MHz) 623 ppm

! H nmr (D 2 0, 400MHz) 57.05 (br. d, IH, J PH 510 Hz), 6.89 (d, IH) ppm

Example 20

Compound 20 (Ph = phenyl)

Compound 21 (Ph = phenyl)

C(CH 3 ) 2 OSi(CH 3 ) 2 C(CH 3 ) 3

To a solution of Compound 14 (262mg, 0.56mmol), triethylamine (0.068ml, 0.67 mmol) and 4-dimethylaminopyridine (7mg) in dichloromethane (2.5ml) at 0°C, t-butyldimethylchloro silane (0.16ml, O.όlmmol) is added. The reaction mixture is warmed to 20°C and srirred. After 24 hours, the reaction mixture is evaporated, ether is added, and the resulting solid separated by filtration. The filtrate is evaporated and the residue dissolved in dichloromethane (0.5 ml) and -rie-hylamine (0.078ml) further chlorosilane (84mg) and 4-dimethylaminopyridine (7mg) are added After 18 hours, the reaction mixture is evaporated and the residue is dissolved in ether and filtered. The filtrate is evaporated and the residue is purified by silca gel chromatography.

Compound 21 is eluted with ethyl acetate/hexane :1). and is a mixture two isomers (3:1)

Compound 20 is eluted with ethyl acetate, and is a 2:1 mixture of two isomers

Compound 20:

! P nmr (CDCI3, 24MHz) δ 35.3, 35.0 ppm (2:1) J PH 544 Hz.

! H nmr (CDC1 3 , 400 MHz) δ 7.22 (d, IH, J PH 545 Hz), 5.90 (m, IH) ppm

Compound 21:

31 P nmr (CDCI3. 24MHz) 654.1, 53.9 ppm (3.1)

*H nmr (CDC1 3 , 400MHz) δ 0.76 (s, l Bu), 0.74 (s. "Bu) ppm

Elemental analysis Expected: C59.57, H 8.45, Si 4.79, P 5.3% Found: C59.6, H 8.4, Si 4.6, P5.6%

Example 21

PhCOO

Compound 22 (Ph ' phenyl)

C(CH 3 ) OH

Trifluoroacetic acid (15ml) is added to a stirred solution of Compound 15 (2:1 ratio isomers) (1.55g, 3.62 mmol) in dichloromethane (30ml) at 20°C. After the addition of water (3.9ml), the solution is stirred for 2.25 hours, then evaporated and co-evaporated with toluene at 0.5 mmHg pressure to give Compound 22.

! H nmr (CDC1 3 , D 2 O, 400MHz) δ 5.38 (s), 5.40 (s), 5.46 (d), 5.47 (d) ppm

Example 22

PhCOO

Compound 23 (Ph ■ phenyl)

C(CH 3 )2θH

Compound 22 is dissolved in pyridine (2.9 ml) and acetic anhydride (2.1ml) is added After 43 hours, the reaction mixture is evaporated and the residue purified by silica gel chromatography, to give Compound 23 upon elution with a gradient of ethanol ethyl acetate. The product is obtained as a mixture of two alpha and two beta anomers.

31 P nmr (CDC1 3 , 24MHz) 655.9, 56.7 ppm

! H nmr (CDQ 3 , 400MHz) anomeric proton: 66.03 (s), 6.05 (s), 6.20 (d, J=4.OHz) 6.37 (d, J=4.2Hz) ppm

mass spectrum (CI, NH 3 ) 473 (MH + ), 490 (MNH 4 + ) Elemental analysis Expected: C51.40%, H6.38%, P6.32% C 21 H 29 O 10 P.H 2 O Found: C50.7%, H5.9%, P5.9%

Example 23

Compound 24 (Ph - phenyl)

C(CH 3 )2θH

PhCOO

)

Trifluoroacetic acid (60ml) and water (20ml) are added to a stirred solution of Compound 14 (15.6g, 33.2mmoI) in dichloromethane 000ml). After 3.75 hours, the solution is warmed to reflux for 30 minutes, and then stood at 20°C for 18 hours. The solution is evaporated and co-evaporated with toluene, and the residue dissolved in pyridine (27ml). Acetic anhydride (19ml) is added to the solution, which is then stood at 20°C for 24 hours, whereupon 4-dimethylaminopyτidine 050m g) and acetic anhydride (6ml) are added. After 2 days, the solution is evaporated and purified by silica gel chromatography, Compound 24, the major

product, a mixture of four isomers, is eluted by ethyl acetate and is further purified by chromatography in hexane/ethyl acetate.

31 P nmr (CDC1 3 , 161MHz) 6 54.9, 54.4, 54.0, 53.6 ppm

Compound 25, a single isomer, is obtained by trituration of the late column fractions with ether, to give a white solid

Elemental analysis: Expected: C54.27%, H 5.82%, P 7.78% Found: C54.3%, H 5.7%, P 7.7%

31 P nmr (CDCI 3 : d 4 McOH, 24MHz) 6 81.0 ppm H nmr (CDC1 3 , d 4 MeOH, 400MHz) 6 6.41 (s, IH), 4.80 (dd, IH, J2.1, 5.3Hz) ppm

Example 24

26 yl)

To a solution of Compound 24 00.3g, 20.0mmol) in dichloromethane (30ml), imidazole (4.1g, όOmmol) and then chlorotrimethyl silane (5.1ml, 40mmol) are added, the latter dropwise over 5 minutes. After 2.5 hours, the suspension is diluted with dichloromethane and extracted with water, then brine. The organic phase is dried over magnesium sulphate and evaporated. The residue is Compound 26.

31 P nmr (CDCI3, 161MHz) 654.3, 53.9, 53.4, 52.8 ppm l H nmr (CDCI3, 400MHz) 6 -0.02 - 0.06 (4s, 9H) ppm

Example 25

Compound 27

(Ph = phenyl, T = 1-ιhyminyl)

A suspension of thvmine (l.όόg, 13.2mmol) and bis(trimethylsilyl)acetamide (7.2ml, 29mmol) in 1,2 dichloroethane (20ml) is heated to 70°C for 2 hours, then cooled to 20°C. To this solution, a solution of Compound 26 (7.73g, 13.2mmol) in 1,2 dichloroethane (10ml) is added. Trimethylsilyltriflate (3.1ml, 15.8mmol) is added dropwise to then cooled, the above solution, which is then heated to 50-55°C for 2.5 hours. Aqueous sodium bicarbonate (30ml) is added to the reaction mixture which is stirred for 10 minutes and diluted with chloroform and the aqueous phase extracted three times. The organic phase is separated, washed with brine and dried over magnesium sulphate before evaporation. The residue is purified by chromatography on silica gel, eluting with ethyl acetate. The product, Compound 27, is obtained as two separate isomers.

Earlv fraction

31 P nmr (CDC1 3 , 161MHz) 653.50 ppm

! H nmr (CDC1 3 , 400MHz) 6 6.95 (s, IH) 5.70 (dJH), 5.31 (dd, IH), 4.22 (m, IH) ppm

Late fraction

31 P nmr (CDC1 3 , 161MHz) 653.1 ppm l H nmr (CDC1 3 , 400MHz) 66.88 (s, IH), 5.63 (d, IH), 5.38 (dd, IH), 4.16 (m, IH) ppm

Example 26

yl-deninyl)

Compound 29

(Ph _• phenyl. A j , = N - benzoyladeninyl)

A suspension of N-benzoyl adenine (0.46g, L9mmoI) and bis(trimethylsilyl)_-cetamide (0.96ml, 3.9mmol) in 1,2 dichloroethane (5ml) is heated to 60°C for 1 hour, then cooled. To this, a solution of Compound 26 (l.Og, 1.9mmol) in 1,2 dichloroethane (2ml) is added, Trimethylsilyl triflate (0.94ml, 4.9mmol) is added dropwise to the above solution, which is then heated to 60°C for 1.25 hours. The reaction mixture is subjected to the work-up and purification procedure of Example 25, except that the products, Compound 28 and 29, are eluted with 3% methanol ethyl acetate.

Compound 28 is obtained as two separable isomers the later of which is a mixture with N-benzoyladenine.

31 P __π_r (<_-DCl 3 , 24MHz) eluted first 552 J ppm eluted second S53.7 ppm

*H nmr (CDC1 3 , 400MHz) eluted first 55.85 (s, IH), 5.76 (d, LH), 0.00 (s, 9H) ppm eluted second 65.87 (s, IH), 5.70 (d, IH), 0.00 (s, 9H) ppm

Compound 29 is obtained as partly separable isomers:

31 P nmr (CDCl 3 , 24MHz) eluted third 653.3, 53.0 ppm (3:1 mixture) eluted forth 653.2 ppm

'H nmr (CDC1 3 , 400MHz) eluted third 66.08 (s,lH), 5.92 (d, IH), ppm minor isomer listed eluted forth 66.01 (s, IH), 5.86 (d, IH) ppm

Elemental Analysis Expected: C58.87%, H 5.81%, N 10.10%, P 4.47% Found: C58.6%, H6.0%, N10.0%, P 4.2%

Example 27

Compound 30

(Ph = phenyl. A j , - N - benzoyladeninyl)

A solution of Compound 29 (0.44g, 0.63mmol) is methanol (5ml) and aqueous ammonia (30%, 8ml) is heated to 50°C for 1 hour, then allowed to stand at 20°C for 18 hours prior to evaporating to dryness. The residue is taken up in water and extracted with chloroform three times. The aqueous layer is subjected to purification by ion exchange chromatography on Dowex 50W x 2H*\ eluting with H 2 O then 3.5% aqueous ammonia. The product containing fractions are further chromatographed on Dowex 50W x 2 - NH 4 * (water elurion). The product obtained is dissolved in water, filtered and then subjected to chromatography on Dowex - 50W x 2H* eluting with methanol then dilute aqueous ammonia. The product. Compound 30, is obtained as a white solid after freeze-drying.

31 P nmr (D 2 0, 24MHz) 643.4 ppm l H nmr (D 2 0, 400MHz) 68.15 (s, IH), 7.74 (s, IH), 5.86 (s, IH), 4.66(d, IH), 1.30 (s, 3H), 1.26 (s,

3H) ppm

Elemental Analysis Expected: C38.18%, H 6.65%. N 19.09%, P 7.04% C^H^iO^P.lH O Found: C38.7%, H 6.5%, N 18.4%, P 6.5%

Example 28

Compound 31

PhCOO (Ph * phenyl T _« 1-thyminyl)

To a solution of Compound I 0-Og, 2.5mmol) in methanol (10ml) a solution of potassium carbonate in water (0.17g/0.25ml) is added dropwise over 30 minutes. After 1 hour at 20°C, the reaction mixture is kept at -15°C for 50 hours, then warmed to 20°C for 5 hours. Acetic acid is added, until neutral, and the solution is evaporated The residue is purified by silica gel chromatography, eluting with ethyl acetate, to give Compound 31.

! H nmr (CDC1 3 , 400MHz) 6 7.24, (d, IH, J0.9Hz), 5.95 (d, IH, Jό.lHz), 5.57 (s, IH), 5.33 (s,: IH) ppm

Elemental Analysis: Expected: C60.33%, H 5.06%, N 7.82%, Found; C60.0%, H 5.2%, N 7.6%

Example 29

Compound 32

PhCOO (Ph = phenyl T = 1-thyminyl)

C(CH 3 >3

To a solution of Compound 31 (0.21g, 0.59mmol) in a mixture of dimethylformamide (1ml) and chloroform, (1ml), imidazole (60mg, 0.88mmol) and chlorodiphenyltertbutylsilane (0.17ml, 0.65mmol) are added. After 3 days the reaction mixture is diluted with water and extracted with ethyl acetate. The organic phase is washed with water and brine, dried over magnesium sulphate and evaporated The residue is purified by silca gel column chromatography, eluting first with 2:1 ethyl acetate hexane then rc-chromatographed with a 1:1 mixture of the above solvents, to give Compound 32.

! H nmr (CDC1 3 , 400MHz) δ 6.50 (s, IH), 5.98 (d, IH), 5.50 (s, = IH), 5.34 (s, = IH), 1.08 (s, IH) ppm

Example 30

33

l-thyminyl)

A solution of Compound 32 (0.20g, 0.34mmol) and BCHPC (13mg, 0.03mmol) in toluene (0.3ml) is added dropwise to Compound B (56mg, 0.40mmol) at 75°C under argon. After 3 hours, additional BCHPC (13mg) is added, and after a further 2.75 hours, BCHPC 03mg) is

added After a further 7 hours, the solution is cooled, evaporated, and the residue purified by silica gel chromatography, eluting with a gradient of hexane/ethyl acetate. The product, Compound 33, is obtained as a mixture of four isomers.

31 P nmr (CDC1 3 161MHz) 658.0, 57.7, 56.3, 56.1 ppm

The product can be further purified by HPLC, to give a mixture of three isomers.

*H nmr (CDC1 3> 400MHz) 66.18 (s, HI 1 ), 6.10 (d, HI 1 ), 6.01 (d, HI 1 ), 3.88 (d, OCH^), 3.80 (d, OCH- , 3.73 (d, OCHQ ppm

Example 31

---hyminyl)

A solution of Compound I (0.40g, l.OOmmol) and BCHPC (40mg, O.lmmol) in toluene (0.5ml) is added dropwise over 30 minutes to Compound B (0.28g, 2.0mmol) at 80°C under argon. After 2.2 hours the reaction mixture is cooled, evaporated and purified by chromatography as silica gel, during with tetrahydrofuran. The product Compound 34, is obtained as a mixture of four isomers.

31 P nmr (CDC1 3 , 24MHz) 655-2, 55.0 ppm

! H nmr (CDC1 3 , 400MHz) δ 3.73 (d), 3.75 (d), 3.78 (d), 3.85 (d) [P-O αy ppm

Elemental Analysis: Expected: C51.9, H 5.8, N 4.2, P 5.0%

Found: C51.80, H 5.99, N 5.03, P 5-57%

C_ 4 H3 1 - 2O.0P.H2O

Example 3.

35 1-thyπunyl)

A solution of Compound I (4.00g, lO.Ommol) and BCHPC (0.3g, 0.75mmol) in toluene (7ml) is added dropwise to ethyl 0.1-die-hoxyethyl)phosphinate (4.20g, 20.0mmol) over 85 minutes at 80°C, under an argon atmosphere. Further BCHPC (0.5g, 1.25mmol) is added to the reaction mixture over 16 hours. The resulting mixture is subjected to shoπ path distillation 000°C/0.03 mbar) and the residue is purified by silica gel column chromatography, eluting with a gradient of chloroform/methanol 000:0 - 98:2). The product is obtained as a mixture of ribo- and xylo- isomers.

31 P nmr (CDC1 3 , 24MHz) 546.0, 45.9, 45.8, 45.7 ppm

Further purification by column chromatography, using a gradient of 2% to 20% ethanol in chloroform gives Compound 35 as a mixture of two xylo-isomers.

31 P nmr (CDC1 3 , 24MHz) 6 46.0, 45.8 ppm l nmr (CDC1 3 , 400MHz) 66.07, (d, HI 1 ), 6.05 (d, HI 1 ), 5.54 - 5.48 (m, IH) ppm

Example 33

1-ιhymmyl )

To a solution of Compound 35 (0.35g, 0.57mmol) in chloroform (5ml) and ethanol (0.8ml), chlorotrimethylsilane (0.22ml. ' " mmol) is added dropwise. After 1 hour, a further quantity of the silane (1.0ml) is added Aft-x 4 hours, .e solution is evaporated to give crude Compound 36.

31 P nmr (CDC1 3 , 161MHz) 636.7, 36.5 ppm J PH 540 Hz

Example 34

37 « 1-thyminyl)

Aqueous ammonia (33%, 10ml) is added to a solution of crude Compound 36 (0.28g) in methanol (3.5ml). After 20 hours at 20°C, the solution is heated to 70°C for 1.5 hours. After cooling, the solution is evaporated, dissolved in water and extracted with chloroform. The aqueous phase is purified on an ion exchange resin (Dowex -H + ). The product is freeze-dried to give Compound 37 as a white solid.

31 P nmr (D 2 0, 161MHz) 6 31.7 ppm

Due to PH-PD exchange : 631.3 (t, J PD 83 Hz)

*H nmr (D 2 O, 400MHz) 67.09 (d, J PH 555 Hz), 5.71 (d, IH, J 7.0Hz) ppm

Example 35

To a solution of 5'O-mphenylme-hyluridine (21.5g, 0.044mol) in pyridine (25ml) at 0°C, chlorodimethylthexylsilane (9.2ml, 0.046mol) is added dropwise. The suspension formed is stirred for 12 hours and stood for 58 hours at 20°C. The solid is filtered off and the filtrate evaporated. The residue is purified by silica gel column chromatography, eluting with chloroform. The Compound 38, is further purified by crystallisation (ether/chloroform).

l U nmr (CDC1 3 , 400MHz) 6 -0.15 (s, 3H), 0.00 (s, 3H); 5.25 (d, IH, J8.1 Hz), 5.84 (d, IH, J3.7Hz), 7.75 (d, IH, J 8.2Hz) ppm

Example 36

Acetic anhydride (6.3ml, 67mmol) is added to a suspension of pyridinium dichromate in dichloromethane at reflux. After 10 minutes, a solution of Compound 38 04.0g, 22mmol) in dichloromethane (40ml) is added to the now black solution over 30 minutes. After 1 hour, ether/hexane (1:1) is added to the reaction mixture, which is then allowed to cool. The solution is filtered through 'Hi-flo', evaporated, dissolved in ether and refiltered through 'Hi-flo'. Evaporation of the filtrate under high vacuum gives Compound 39 which is used crude in Example 37.

H nmr (CDCI 3 , 400MHz) δ 4.12 (m,lH), 4.43 (d, 8.0Hz), 5.27 (dd, LH, J8.2, 2.0Hz), 6.13 (d, IH, J8.0Hz) 7.50 (d, IH, J 8.2Hz) ppm

Example 37

n-Butyllithium (1.6M in hexanes, 27.0ml, 43.2mmol) is added to a suspension of triphenylmethylphosphonium bromide 05.5g. 43.4 mmol) in tetrahydrofuran 015ml) at -60°C.

After 1 hour, a solution of Compound 39 (12.4g, 19.8mmol) in tetrahydrofuran (25ml) is added dropwise at -70°C. After 4 hours at -70°C, the suspension is allowed to warm slowly to 20°C. The suspension is receded to -20°C and acetic acid (1.85g) is added The solvent is evaporated and ether added to the residue. The mixture is filtered and the filtrate evaporated and purified by chromatography (silica gel), eluting the product with an ethyl acetate/ether gradient.

»H nmr (CDC1 3 , 400MHz) 67.73 (d, IH, J8.1H- , 5.85 (d, IH, J6.2Hz), 5.30 (t, IH, J2.0Hz), 5.21 (dd, IH, J2.2, 8.1 Hz), 5.10 (t, IH, J 2.0Hz) ppm

Example 38

A solution of Compound 40 (0.50g, 0.8mmol) and BCHPC (32mg, 80μmol) in toluene (2ml) is added to Compound B (0.33g, 2.4mmol) over 15 minutes at 80°C, under an argon atmosphere. After SO minutes, BCHPC (32mg) is added After a further 3 hours and 7 hours BCHPC (32mg) is again added. After a further 4 hours, the reaction mixture is cooled, evaporated and the residue purified by silica gel chromatography, eluting with ethyl acetate. The first product-containing fractions eluted give Compound 41 as a mixture of three isomers.

31 P nmr (CDC1 3 , 24MHz) 657.3, 55.8, 55.7 ppm

! H nmr (CDC1 3 , 400MHz) 65.90 (d, IH), 5.87 (d, H), 5.78 (s, lH)ppm

Later fractions contain mainly one isomer of the product, together with excess Compound B, the majority of which is removed by dissolving the mixture in ethyl acetate and washing the solution five times with water. The product is recovered by drying the solution with magnesium sulphate, and evaporation.

31 P nmr (CDC1 3 , 161MHz) 6 56.2 ppm

! H nmr (CDC1 3 , 400MHz) δ 5.78 (s, IH) ppm

Example 39

Compound 42 (Ph = phenyl)

(CH 3 >2 OH

A solution of Compound H (0.46g, 1.4mmol) and BCHPC (55mg, 0.14mmol) in toluene (1.5ml) is added dropwise to Compound B (0.22g, l.όmmol) in toluene (1ml) at 80°C, under argon. After 2.5 hours, further BCHPC is added After a further 2 hours more BCHPC is added and heating maintained at 70°C for 3 hours. The resulting mixture is evaporated and the residue purified by silica gel column chromatography. Compound 42, a mixture of four diastereoisomers, is obtained on eluting with an ethanol (0-5%) / ethylacetate gradient.

31 P nmr (CDC1 3 , 24MHz) 655.8, 55.4, 55.1, 54.7 ppm

! H nmr (CDC1 3 , 400MHz) 56.10 (sjil), 6.13 (s,Hl), 6.42 (d, HI, J4.1Hz), 6.44 (d, HI, J4.3Hz) ppm

Elemental Analysis: Expected: C53.39, H 6.19, P 6.56% Found: C53.2, H 6.3, P 6.1%

Example 40

Compound 43 (Ph = phenyl)

(OCH 2 CH 3 ) 2

Dowex 50w x -2 (H*) ion-exchange resin (iml) is added to a solution of Compound 17 (150mg : 0.31mmoi) in 1,2 dime hoxye-hane (2ml). The mixture i- heated to 70°C for 12 hours. The resin is filtered off and washed with tetrahydrofuran. The filtrate is evaporated and co-evaporated with toiuene three times, to give Compound 43 as a mixture of isomers.

31 P nmr (CDC1 3 , 24MHz) 645.7, 45.6 ppm

Example 41

PhCOO

Compound 44 (Ph = phenyl)

Pyridine (0.25ml) and acetic anhydride (0.17ml) are added to crude Compound 43. The solution is allowed to stand for 41 hours and then evaporated. The residue is dissolved in toluene and filtered The toluene is evaporated to give Compound 44 as a mixture of four isomers.

31 P nmr (CDC1 3 , 24MHz) δ 672, 65.0 ppm

! H nmr (CDC1 3 , 400MHz) 66.43 (s, HI), 6.34 (s, HI), 6.25 (s, HI), 6.11 (s, HI) ppm

Example 42

Compound 45 (Ph = phenyl)

To a solution of Compound 17 (150m g, 0.31mmol) in acetic acid (1.2ml) acetic anhydride (0.44ml) and p-toluenesulphonic acid 05mg) are added. After 50 hours, the reaction mixture is added to iced water, which is then neutralised with sodium bicarbonate solution, and extracted with chloroform three times. The organic phase is dried over magnesium sulphate and evaporated The residue is purified by silica gel chromatography, eluting with a petroleum spirit/ethyl acetate gradient. The product. Compound 45, is obtained as a mixture of two alpha anomers.

X nmr (CDC1 3 . 400MHz) 67.14 (d, PH, J 550 Hz), 6.28 (d, HI), 6.25 (d, HI), 1.50, 1.52, 1.54 (3 x s, (CH 3 ) : 0 ppm

Example 43

Compound 46

PhCOO (Ph = phenyl)

CH 3 CH 2 0

-2- (OCH 2 CH 3 )2

To a degassed solution of Compound E (2.8g, 1L7 mmol) in toluene (1ml) under an argon atmosphere at 80°C. a solution of Compound G (2.0g, 6.9mmol) and BCHPC (0.2g) in toluene (3ml) is added dropwise over 20 minutes. The reaction is maintained at 75-80°C and after 2 hours and 3 hours further BCHPC (2 x O.lg) is added After a further 5 hours, the reaction mixture is cooled and purified by silica gel column chromatography, eluting with an ethanol/ethyl acetate gradient, to give Compound 46 as a mixture of two diastereoisomers.

31 P nmr (CDC1 3 , 161MHz) 545.13, 45.09, 44.93, 44.90, 20.27, 20.25 ppm

mass spectrum CI. (NH 3 ) 536 (MH + ), 553 (MNH 4 " )

Example 44

Compound 47 (Ph = phenyl T » 1 - thyminyl)

OCH 2 CH(CH 3 )2

A solution of an aldehyde of formula XXHI where R 5 a is hydrogen, R 6 is l-thyminyl and R 7 is teπ-butyldiphenylsilyl, prepared as described in WO 92 20823 (2.00g, 4.05 mmol) in THF (18ml) is added dropwise over 20 minutes to a solution of isobutyl methylphosphinate (0.55g, 4.1mmol) and DBU (0.60ml, 4.1mmol) in THF (7ml). After 3 hours, more of the phosphinate (0.06g) is added. After 4 hours, additional DBU (0.30ml) and the phosphinate (0.27g) are added. The reaction is then stored at -18°C for 60 hours, warmed to 20°C for 2 hours and then evaporated. The residue is purified by silica gel chromatography, eluting with 7% ethanol/chloroform. Compound 47 is obtained as a mixture of four isomers.

31 P nmr (CDC-3, 161MHz) δ 52.9, 52.5, 51.9, 51.4ppm

! H nmr (CDC1 3 , 400MHz) 6.20 (t, HI 1 ), 6.27 (t, HI 1 ), 6.32 (t, HI 1 ) ppm

- /•

Example 45

Compound 48

= 1 - rJπyminyl pt = p - tolyl

OCH 2 CH(CH 3 >2

To a solution of Compound 47 (0.79g, 1.26mmol) and 4-dimethylaminopyridine (0.46g, 3.8mmol) in dichloromethane/acetonitrile (1:4, 25ml) at 0°C, p-tolylchlorothionoformate (0.39ml, 2.5mmol) is added over 5 minutes. After 0.5 hours, the reaction mixture is stored for 18 hours at - 18°C. The mixture is then warmed to 20°C and an additional amount of the formate (0.27ml) added in two batches over 6 hours. The reaction mixture is diluted with dichloromethane, evaporated onto silica gel, and purified by column chromatography. The product, Compound 48 as a mixture of four isomers, is eluted using a gradient of 0-10% ethanol/ethyl acetate.

31 P nmr (CDC1 3 , 161MHz) δ 47.6, 47.4, 46.3, 45.6 ppm *H nmr (CDC1 3 , 400 MHz) δ 2.28 (s, Ar-CH 3 ) ppm

Elemental Analysis: Expected: C60.28, H 6.70, N 3.52, S 4.02, P 3.89% j oH5.N2O j .PSSi.H2O

Found: C60.95, H 6.9, N 3.8, S3.6, P 3.8%

Example 46

Compound 49 T = 1 - thyminyl)

OCH ; CH(CH 3 )2

A solution of Compound 48 (0.38g, 0.49mmol) and tris(trimethylsilyl) silane (0.30ml, 0.98mmol) in toluene 03ml) is heated to 100°C, under an argon atmosphere, and azo bis(isobutyronitrile) (AIBN) (21mg) in toluene (l.όml) is added batchwise in ten portions over 5.5 hours. The resulting mixture is cooled, evaporated, and the residue purified by silica gel chromatography, eluting the product with 0-5% ethanol in chloroform. Compound 49 is obtianed as a mixture of two diastereoisomers (1:1).

31 P nmr (CDC1 3 , 161MHz) 6 52.4, 52.3 ppm

! H nmr (CDC1 3 , 400MHz) 61.45 (d, PCH 3 , J 13.5Hz), 1.46 (d, PCH 3 , J13.5 Hz)

Elemental Analysis: Expected: C60.93, H 7.46, N 4.44, Si 4.45, P 4.91% C 2 _H 45 N 2 O 6 PSi.H 2 O Found: C60.8, H 7.6, N 4.6, Si 3.9, P 4.

Example 47

ompound SO 1 - thyminyl)

(CH 3 CH 2 }NH

Sodium hydroxide solution (1M, 0.6ml) is added to a solution of Compound 49 069mg, 0.275mmol) in methanol (1.2ml). The solution is heated to 40°C for 19 hours and then additional sodium hydroxide solution OM, 2ml) and lithium hydroxide solution (1.5M, 0.9ml) are added at 20°C and the mixture is stirred at 20°C for 48 hours. Triethylammonium Dowex W x 2 - ion exchange resin is added to the reaction mixture. The resin is washed with water and methanol, and the washings are evaporated The residue is triturated with ether five times to give Compound 50 as a white solid

31 P nmr (d 4 -MeOH, 161MHz) 6 38.7 ppm

! H nmr (d 4 -MeOH, 400MHz) δ 1.18 (d, PCH 3 ), 6.00 (d, IH) ppm mass spectrum (FAB * ) 341 (MNa + )

Example 48

Ph

CH 3 . (OCH 2 CH 3 ) 2

To a solution of the aldehyde used in Example 44 (0.75g, 1.49 mmol) in THF, Compound J (0.32g, 1.79mmol) is added, followed dropwise by DBU (0.22ml, 1.5mmoI). After 6 hours, the reaction is concentrated and the residue purified by silica gel column chromatography. The product is eluted with a gradient of 0-8% methanol/chloroform to give Compound 51 as a mixture of four diastereoisomers.

31 P nmr (CDCI3, 161MHz) δ 52.1, 51.4, 50.5, 48.1 ppm mass spectrum (FAB + ) 673 (MH + ), 695 (MNV)

Example 49

Ph

Compound 52 = phenyl T = 1 - thyminyl)

CH 3 - (OCH 2 CH 3 )2

A solution of Compound 48 (0.76g, l.lmmol) and acetic anhydride (0.16ml) in pyridine (0.27ml) is stirred for 20 hours and then evaporated. The residue is purified by silica gel chromatography, eluting with an ethanol ethyl acetate gradient. Compound 52 is obtained as a mixture of two isomers.

31 P nmr (CDC1 3 , 161MHz) δ 50.2, 46.6 ppm l H nmr (CDC1 3> 400MHz) δ 3.20 (m, H3 1 ), 3.30 (m, H3 1 ) mass spectrum (FAB * ) 715 (MH + ) 737 (MNa÷)

Example 50

Ph

Compound 53 1 - thyminyl)

H C (OCH 2 CH 3 )2

Compound K (0.16ml, O.όmmol) is added dropwise to a solution of the aldehyde used in Example 44 (250mg, 0.51mmol) in pyridine (0.01ml) and dichloromethane (3ml). After 4 houπ, DBU (0.022ml) is added, and after a further hour, the solution is concentrated and co-evaporated with methanol then toluene. The residue is purified by silica gel column chromatography,

eluting with 5% ethanol/chioroform to give Compound 53 as a mixture of two isomers.

31 P nmr (CDC1 3 , 161MHz) 6 38.9, 38.7 ppm

Further chromatography of impure fractions gives the product as a mixture of four isomers.

31 P nmr (CDC1 3 , 161MHz) δ 38.9, 38.7, 38.1, 37.8 ppm mass spectrum (FAB * ) 689 (MH~), 711 (MNa * )

Example 51

Ph

Compound 54

- thyminyl)

OCH 2 CH 3

To a solution of ethyl phenylphosphinate (83mg, 0.49mmol) in dichloromethane (2ml), bis(trime-hylsilyltrifiuoroace-amide) (0.52ml, 1.95mmol) is added. After 0.25h, a solution of the aldehyde used in Example 44 (0.195g, 0.39mmol) in dichloromethane (2ml) is added. The resulting solution is stored at 10°C for 50 hours, then evaporated. The residue is purified by dry flash chromatography on silica gel. The product, Compound 54 as a mixture of isomers, is eluted bv 1% ethanol/ethvl acetate.

31 P nmr (CDC1 3 , 161MHz) δ 38.2, 37.9 ppm l H nmr (CDC1 3 , 400MHz) δ 6.17 (t, HI 1 ), 6.11 (t, HI 1 ), 6.03 (t, HI 1 ) ppm

Example 52

Compound 55 (Ph = phenyl)

To a solution of Compound 8 (0.83g, 1.23mmol) in tetrahydrofuran (6ml) at -70°C, n-butyllithium (0.85ml, 1.35mmol) is added over 1 minute. After 10 minutes, a solution of Compound L (0.25g, 1.23mmol) in tetrahydrofuran (4ml) is added over 1 minute. After 2 hours at -70°C, the mixture is slowly warmed to 0°C, then re-cooled to -55°C, whereupon saturated ammonium chloride solution (10ml) is added The aqueous mixture is extracted with dichloromethane three times. The organic phases are dried over magnesium sulphate, evaporated, and the residue purified by chromatography on silica gel. The product, Compound 55, consists of two separable isomers.

Less polar isomer

31 P nmr (CDC1 3 , 24MHz) δ 39.7 ppm

] H nmr (CDC1 3 , 400MHz) 66.50 (dd, IH), 6.60 (dd, IH) ppm

More polar isomer

31 P nmr (CDC1 3 , 24 MHz) 639.9 ppm

*H nmr (CDC1 3 , 400MHz) 66.18 (ddd, IH), 6.89 (ddd, IH) ppm mass spectrum CI. (NH 3 ) 717 (MH + )

Example 53

CϋiupϋUΩu 5u

(Ph = phenyl)

A solution of Compound G (0.394g, I.36mmol) and BCHPC (52mg, O.Wmmol) in toluene (0.2ml) is added over 10 minutes to a solution of Compound N (0.515g, 1.29mmol) in toluene (0.2ml) at 80°C, under argon. BCHPC (50mg) is added over the next 9 hours in small batches. Also, after 5 hours an additional quantity of Compound G (O.lOg) is added. The reaction mixture is purified by silica gel column chromatography, and the product, Compound 56 as a mixture of two isomers, is eluted with ethyl acetate.

31 P nmr (CDC1 3 , 161MHz) 6 54.8, 54.5 ppm

J H nmr (CDC1 3 , 400MHz) 6 5.81 (d, J 3.5 Hz, IH), 5.65 (d, J 3.8Hz), 5.61 (d, J 3.8Hz) ppm

Example 54

PhCOO

und 57 phenyl)

A solution of Compound 56 (O.lόg, 0.23mmol) in 1,2 dimethoxyethane (2ml) containing Dowex 50 w x 2- H + ion exchange resin (8ml) is heated to 80°C for 15 hours. The reaction is cooled, filtered, and evaporated. Proton NMR shows the loss of both isopropylidene groups and the iso-butyl ester group. The residue is dissolved in a solution of acetic anhydride (0.94ml), pyridine (l.όml) and dichloromethane (2ml). After 18 hours, the solution is evaporated, diluted with water and extracted with chloroform. The organic phase is dried over magnesium sulphate, and evaporated. Compound 57 is obtained as a mixture of isomers.

31 P nmr (CDC1 3 , 161MHz) 6 84.0, 83.5, 83.1 ppm

Example 55

Compound 58 (Ph = phenyl)

A solution of Compound O (0.107g, 0.47mmol) and BCHPC (24mg, 0.062mmol) in toluene (0.75ml) is added dropwise over 12 minutes to a solution of Compound 18 (0.24g, 0.62mmol) in toluene (0.5ml) at 80°C, under an argon atmosphere. The mixture is heated for 6 hours and BCHPC (4 x lOmg) is added during the course of the reaction. The resulting mixture is evaporated and the residue purified by silica gel chromatography. The product, Compound 58 as a mixture of two isomers, is eluted by a gradient of ethanol (0 to 5%) in ethyl acetate.

31 P nmr (CDC1 3 , 161MHz) 6 54.8, 54.4 ppm

! H nmr (CDC1 3 , 400MHz) 6 5.86 (t, IH), 5.75 (d), 5.71 (d) ppm

Example 56

Compound 59 (Ph phenyl)

A solution of Compound 58 0I7mg, 0.19mmoi) in trifluoroacetic acid (1.2ml) water (0.3ml) and dichloromethane (1.9ml) is stirred at 20°C for 5 hours, then evaporated and coevaporated with toluene three times. The residue is dissolved in pyridine (0.2ml) and acetic anhydride (0.11ml) is added After 24 hours, additional acetic anhydride (0.04ml) is added After a further 60 hours, the mixture is co-evaporated with toluene, and the residue is purified by silica gel chromatography, eluting with ethyl acetate. Compound 59 is obtained as a mixture of eight isomers.

31 P nmr (CDC1 3 , 161MHz) 6 55.2, 54.4, 53.9, 53.2, 53.1, 53.0, 52.9, 52.8 ppm mass spectrum CI. (NH 3 ) 717 (MNH 4 + )

-_,Xά-T.p_£ 5 I

Compound 60

(Ph __ phenyl)

A solution of Compound Q (58mg, 0.31mmol) and BCHPC (12mg, 0.03mmol) in toluene (0.5ml) is added dropwise to a solution of Compound 4 (llOmg, 0.31mmol) in toluene (0.5ml) at 80°C under argon. The mixture is heated for 13 hours, with additions of extra BCHPC throughout this time. The reaction mixture is evaporated and the residue purified by chromatography on silica gel. The product, Compound 60 as a mixture of two isomers, is eluted with 5% ethanol/chloroform.

31 P nmr (CDQ 3 , 24MHz) 6 57.7, 56.9 ppm

J H nmr (CDC- 3 , 400MHz) 65.79 (d, IH), 5.91 (m, IH) ppm

Elemental Analysis: Expected: C53.31, H 8.03, P 5.49%

Found: C52.9, H 7.8, P 5.2%

mass spectrum C.I. 565 (MH * )

Example 58

Ph

Compound 61 (Ph - phenyl)

A solution of Compound P (2.05g, U.Ommol) and BCHPC (0.31g, 0.8mmol) in toluene (6.5ml) is added over 1.5 hours to a solution of Compound 11 (6.03g, U.Ommol) in toluene (5ml) at 75°C under an argon atmosphere. Further portions of BCHPC (5 x 30 mg) are added over 2 hours, at 30 minute intervals. After this time the mixture is cooled, pre-adsorbed onto silica gel, and purified by chromatography. The product is eluted by a gradient of me_hanol (0-100%) in ethyl acetate. The two isomers of the product, Compound 61 are separated by chromatography.

Less polar isomer

31 P nmr (CDG 3 . 161MHz) 6 61.9 ppm

More polar isomer

31 P nmr (CDC1 3 , 161MHz) 6 62.2, 61.9 (2:1) ppm

Elemental Analysis Expected: C62.27, H 7.84, P 4.23% Found: C62.0, H 8.1, P 4.0%

mass spectrum CI. (NH 3 ) 733 (MH + )

Example 59

Ph

Compound 62 (Ph = phenyl)

To a solution of Compound 61 (1.0g, 1.4mmol) in dichloromethane (3ml) and pyridine 0-lml), acetic anhydride (0.64ml) and 4-dimethylaminopyridine (lOmg) are added The mixture is stirred for 1.5 hours, then evaporated and the residue is purified by chromatography on silica gel, eluting with ethyl acetate. Compound 62 is obtained as a mixture of two isomers.

31 P nmr (CDC1 3 , 161MHz) 6 55.3, 55.8 ppm

Elemental Analysis: Expected: C6I.28, H 7.71, P 3.95, Si 3.57%,

Found: C61.3, H 7.6, P 3.6. Si 3.5% mass spectrum CI. (NH 3 ) 775 (80%, MNH 4 + )

Example 60

Compound 63

To a solution of crude Compound 62 04.6g, 15.3mmol) in tetrahydrofuran (30ml) water (1ml) and pyridine (1ml), a solution of tetra n-butylammonium fluoride trihydrate (5.3g, 16.8mmol) in tetrahydrofuran (25ml) is added over 1.5 houπ. The reaction mixture is maintained at 10°C for 18 hours, then 20°C for 5 houπ before evaporation of solvent, and co-evaporation with toluene to give a residue containing Compound 63.

Example 61

Compound 64

The residue from Example 60 is dissolved in pyridine (3ml) and dichloromethane (25ml), cooled to 0°C, and acetic anhydride (3ml) added The solution is allowed to stand at 20°C for 18 hour, then evaporate The residue is purified by silica gel column chromatography, eluting with 5% methanol/chloroform. Compound 64 is obtained as a mixture of two isomeπ.

31 P nmr (CDC1 3 , 24MHz) 6 54.6, 54.2 ppm

Example 62

Compound 65

To a solution of Compound 61 (2.45g, 3.34mmol) in tetrahydrofuran (8ml), water (1ml) and pyridine (1ml) a solution of tetra n-butyl ammonium fluoride trihydrate(1.05g, 3.34mmol), in tetrahydrofuran (7ml) is added over 1 hour. After 3.5 houπ, a further amount of the fluoride

(1.05g) is added in batches as a solid. The reaction is stood at 20°C for 40 houπ, then evaporated and co-evaporated with toluene. A portion of the material is purified by silica gel chromatography, eluting with 10% methanol/ethyl acetate to give Compound 65 and the remainder is used in subsequent Examples.

! H nmr (CDC1 3 , 400MHz) 65.82 (d,lH), 5.76 (dJH), 1.56 (s,CH 3 ), 1.50(s,CH 3 ), 1.36 (s, CH 3 ), 1.31 (s, CH 3 ) ppm

Example 63

Compound 66 (Ph = phenyl)

To a rapidly stirred solution of crude Compound 65 (255mg, 0.35mmol) in dry tetrahydrofuran (2ml) at 0°C, sodium hydride (31mg, 0.77mmol) is added batchwise over 10 minutes. The mixture is allowed to warm to 20°C, and after 10 minutes, cooled to 0°C, whereupon benzylbromide (0.091ml, 0.77mmol) is added dropwise. The mixture is warmed to 20°C and after 4 houπ, additional sodium hydride (I4mg) is added. After 22 houπ, further benzylbromide (0.013ml) is added, followed 2 houπ later by aqueous ammonium chloride. The aqueous phase is extracted with ethyl acetate, and the organic phase dried over magnesium sulphate and evaporated. The residue is purified by chromatography on silica gel, eluting with gradient of petroleum ether/ethyl acetate, to give Compound 66 as a mixture of two isomeπ.

! H nmr (CDC1 3 , 400MHz) δ 7.38-7.22 (m. 10H), 5.82 (d, IH), 5.69 and 5.66 (2 x d, IH) ppm

- 89 -

Example 64

Compound 67

Acetic anhydride (3.0ml) is added to a solution of Compound 65 0-5g, 3.34mmol) in pyridine

(5ml) and dichloromethane (3ml). After 20 houπ at 20°C, the mixture is concentrated under vacuum and co-evaporated with toluene. The residue is dissolved in ether and filtered The filtrate is evaporated and the residue purified by silica gel chromatography, eluting with 0-5% methanol in ethyl acetate to give Compound 67 as a mixture of two isomeπ:

31 P nmr (CDCI3, 161MHz) 654.8, 54.4 ppm l K nmr (CDC1 3 , 400MHz) 6 2.15 and 2.08 (2 x s, Ac) ppm

Elemental Analysis: Expected: C53.97, H 7.49, P 5.35%

Found: C54.3, H 7.8, P 5.1%

Example 65

Compound 68

A solution of trifluoroacetic acid (0.5ml) in water (0.5ml) is added to a solution of Compound 61 (71mg, O.lmmol) (3:20 ratio isomeπ) in 1,4 dioxan (0.5ml). After 1.5 houπ the solution is evaporated and co-evaporated with toluene three times. Pyridine (0.39ml) and acetic anhdyride (0.18ml) are added to the resulting residue. After 20 houπ, the solution is evaporated and the residue purified by chromatography on silica gel, eluting with ethyl acetate, to give Compound 68 as a mixture of 3 isomcπ.

31 P nmr (CDσ 3 , 24MHz) δ 53.8, 53.5, 53.3 ppm

: H nmr (CDC1 3 , 400MHz) 6 1.33, 1.51 (2 x s, CH^) ppm

Example 66

A solution of trifluoroacetic acid (5ml) in water Oml) is added to a solution of Compound 67 (0.50g, 0.86mmol) in dichloromethane 0-5ml). The resulting solution is stirred for 4 houπ, evaporated, co-evaporated with toluene and the residue is purified by ion exchange chromatography on Dowex 50 W x 2-H + , eluting with water, to give Compound 69 as a mixture of isomeπ.

31 P nmr (D 2 0, 161MHz) δ 63.2, 63.0, 62.8, 62.7, 62.6, 62.4, 62.3 ppm

Example 67

Compound 70

To a solution of Compound 69 in dichloromethane (1ml), pyridine (1.1ml) at -10°C, acetic anhydride (0.5ml) and 4-dimethylaminopyridine (6.5mg) are added The reaction mixture is maintained at 10°C for 60 houπ, 20°C for 18 houπ and then evaporated The residue is purified by silica gel chromatography, eluting with 0-5% methanol in ethyl acetate, to give Compound 70 as a mixture of eight isomeπ.

31 P nmr (CDC1 3 , 161MHz) δ 54.6, 54.5, 54.4, 54.0, 53.9, 53.3, 53.1, 53.0 ppm mass spectrum CI. (NH 3 ) 684 (MNH 4 + )

Example 68

o a solution of Compound 61 (0.81g, l.llmmol) in dry dichloromethane (3ml) at 0°C, pyridine

(0.13ml) and 1-naphthoylchloride (0.20ml, 1.33mmol) are added dropwise. Finally 4-dimethylaminopyridine (8m g) in dichloromethane (0.1ml) is added dropwise. After 22 houπ, the reaction mixture is evaporated, and the residue is purified by silica gel chromatography. The product. Compound 71 as a mixture of two isomeπ, is eluted with ethyl acetate.

31 P nmr (CDC1 3 , 24MHz) 6 54.5, 54.0 ppm

Example 69

To a solution of Compound 71 (0.70g, 0.79mmol) in dichloromethane (2ml) at 0°C, tetra n-butyl ammonium fluoride (1M solution in THF, 1.0ml) is added dropwise. The solution is allowed to warm to 20°C and after 2 houπ, additional tetra-n-butylammonium fluoride (0.5ml) is adde After 4 houπ the reaction is evaporated, and the residue is purified by dry flash chromatography on silica gel, eluting with ether then ethyl acetate, to give Compound 72 as a mixture of two isomeπ.

J H nmr (CDC1 3 , 400MHz) 65.90 (m, IH), 5.78 and 5.75 (2 x d, IH), 5.04 (t, IH) ppm

Example 70

To a solution of Compound 72 (0.33g, 0.51mmol) in pyridine (0.24ml) acetic anhydride (0.23ml) and 4-dimethylaminopyridine (6mg) are added. The mixture is stood overnight, then evaporated The residue is purified by chromatography on silica gel. Compound 73, a mixture of two isomeπ, is eluted with ethyl acetate.

31 P nmr (CDG 3 , 24MHz) 653.6, 54.0 ppm

Example 71

Compound 74 1 - thyminyl)

A solution of Compound 27 015mg, 0.177mmol) in a solution of tetrahydrofuran, acetic acid and water (5ml, 4:1:1) is heated to 60°C for 6 houπ, cooled, evaporated and the residue is co-evaporated with toluene three times.

The product Compound 74, is used directly in the next Example.

31 P nmr (CDC1 3 , 24MHz) 6 53.4 ppm

Example 72

Compound 75

\

A solution of Compound 74 (124mg, 0.21mmol) in methanol (6ml) and DBU (0.16ml, Llmmol) is stirred at 20°C for 2 hours, then evaporated The residue is purified by ion exchange chromatography, on Dowex 50W x 2 -H + resin. The product is eluted with water, and freeze-dried to give Compound 75 as a white solid

31 P nmr (D j O, 161MHz) 6 33.3 ppm l nmr 0- 2 0, 400MHz) 6 7.08 (d, PH, J PH 550 Hz) ppm

Example 73

Compound 76 (T " 1 - thyminyl)

A solution of Compound 27 060mg, 0.246mmol) in methanol (3ml) and aqueous ammonia (33%, 6ml) is stiired for 3 days at 20°C, then evaporated. The residue is purified by ion exchange resin - Dowex - 50W x 2 H* - to give Compound 76 as a white solid after freeze -drying

31 P nmr (D 2 0, 161MHz) δ 53.7 ppm H nmr (D 2 O, 400MHz) 6 1.35 (s, 3H), 1.40 (s, 3H) ppm

Example 74

Compound 77

(Ph = phenyl)

Compound V (260mg, 1.0mm) is dissolved in dry toluene (2ml) and evaporated in vacuo to afford an oily gum. To this product, under argon, is added, at 90°C with stirring, a mixture of Compound G (285mg, 1.0mm), biscyclohexylperdicarbonate (40mg, 0.1mm) and toluene (0.4 ml) over 20 minutes. When addition is complete, the mixture is heated at 80°C for 30 minutes. A few milligrams of biscyclohexyl perdicarbonate is added and heating continued for 30 minutes. This process is repeated 3 times until thin layer chromatography indicates significant product formation. The reaction mixture is purified by column chromatography over silica gel, eluting with chloroform, then 1-15% ethanol: chloroform mixtures. Further purification by column chromatography over silica gel, eluting with 2-8% ethanol: chloroform mixture gives Compound 77 as a colourless oil.

J H nmr (δ, CDC1 3 ) 8.10 (2H, m, Ph-H), 7.70 ( , Ph-H), 7.42 (2H, m, Ph-H), 5.84 (IH, t, C-l), 5.78 (IH, d, C-l*) ppm

31 P nmr (δ, CDC1 3 ) 61.7 and 61.4 ppm.

Example 75

Compound 78 (Ph _- phenyl)

Compound 77 (80mg) is partitioned between dichloromethane (2.0ml) and water (0.3ml) and trifluoroacetic acid 0-2ml) is added. The resulting solution is allowed to stand at room temperature for 1 hour, when L1.C. shows reaction to be complete. Toluene (2ml) is added to the reaction mixture and the solvents evaporated. The resulting residue is co-evaporated with more toluene (3 x 2ml) and dried at high vacuum to afford Compound 78.

31 P nmr (CDC1 3 , D4 MeOH) δ 59.74, 59.60, 58.82, 58.66

Example 76

Compound 79 (Ph » phenyl)

Compound 78 (60mg) is dissolved in acetic anhydride (1ml) and pyridine (1ml). The solution is allowed to stand at room temperature for 3 houπ. Evaporation of the solvents leaves a residue which is co-evaporated with toluene (3 2 ml). Drying at high vacuum gives crude product which is purified by column chromatography over silica gel, eluting with ethyl acetate, to give Compound 79.

31 P nmr (CDC1 3 ) 654.40, 54.22, 53.92, 53.56, 53.27, 53.10, 52.95

Example 77

Ph

To a mixture of the aldehyde used in Example 44 (3I6mg, 0.64mmol) and ethyl (U-diethoxyethyDphosphinate (200mg, 0.95mmol) in THF 05ml) is added DBU (95μl, 0.64mmol) and the resulting mixture is stirred at room temperature for I hour. Concentration and passage through a shoπ coiumn of silica with dichloromethane - ethanol (3:1) and reconcentration gives a crude product which is further purified by flash silica column chromatography (eluant ethyl acetate; ethanol, 30:1) to give Compound 80 as a white solid, isolated as a mixture of four diastereoisomeπ.

31 P nmr ! H decoupled (CDC1 3 , 162MHz) δ 42.1, 40.9, 40.0 and 39.7 ppm

Example "8

To a stirred solution of Compound 80 (300mg, 0.42mmol) and dimethylaminopyridine (51mg, 042mmol) in dry dichloromethane (10ml) under an argon atmosphere is added triethylamine (78μl, 0.56mmol). The resulting mixture is cooled to 0°C and p-tolychlorothionoformate (86μl, 0.56mmol) is added dropwise over 2 minutes. The resulting solution is stirred at room temperature for 24 houπ, followed by the addition of further quantities of triethylamine (58μl, 0.42mmol) and p-tolylchlorothionoformate (65μl, 0.42mmol). The resulting mixture is heated under reflux for 6 houπ. Concentration and purification of the product by flash silica column chromatography (eluant: hexane-ethylacetate 1:1) gives Compound 81.

31 P nmr H decoupled (CDC1 3 , 162MHz) 637.4 and 35.7 ppm

Example 79

The aldehyde used in Example 44 and Compound D are reacted in the presence of DBU

following the procedure of Example 77, but stirring at room temperature for 2.5 houπ. Acetic acid (1.1 equivs) is added and the mixture is concentrated under vacuum. Purification by repetitive flash chromatography fiπtly with ethyl acctate-ethanol (25:1) as eluant followed by chloroform-ethanol (30:1) as eluant, gives Compound 82 as a white solid isolated as a mixture of 4 diastereoisomers.

Found: C59.4, H 7.2. N 4.1%;

C 34 H 49 N 2 O 8 PSi.H 2 O requires C 59.1, H 7.45, N 4.05%

31 P nmr : H decoupled (CDC1 3 , 162MHz) 6 49.0, 48.4, 48.2 and 48.0 ppm

Example 80

Compound 83

thyminyl)

To a solution of ethyl (1,1-diethoxyethyl) phosphinate (5.51g, 26.2mmol) in dry THF (170ml), under argon, at -78°C is added a solution of potassium bis(trimethylsilyl) amide (34.6ml, 0.75M solution in toluene) dropwise over 5 minutes. The resulting solution is stirred at -78°C for 1 hour. A solution of Compound X (5.0g, 8.25 mmol) in dry THF (20ml) is then added dropwise over 5 minutes. Stirring is continued at -78°C for 1 hour before warming to room temperature over 2 houπ. Saturated aqueous ammonium chloride (50ml) is then added and the whole mixture extracted with ethyl acetate (500ml). The organic phase is washed with saturated ammonium chloride (2 x 50ml) and water (2 x 50ml), dried over magnesium sulphate and concentrated Purification by flash silica column chromatography (eluant ethylacetate: ethanol 30:1) gives compound 83 as a mixture of 2 diastereoisomeπ.

Example 81

Ph

Trimethylsilychloride (4.44ml, 35mmol) is added dropwise (2 minutes) at room temperature to a stirred solution of Compound 83 (2.4g, 3.5mmol) in chloroform (25ml) containing ethanol 0%) under argon. After standing at -20°C for 60 houπ, a further portion of trimethylsilylchloride (2.22ml, 17.5mmol) is added along with ethanol (200μl) and the resulting solution stirred at room temperature for 7 houπ. Concentration and co-evaporation with chloroform (50ml) gives a white solid which is purified by flash silica column chroma'tography (eluant chloroform: ethanol 13:1) to give Compound 84 as a white solid isolated as a mixture of 2 diastereoisomeπ.

Found: C 59.95, H 7.25, N 4.65% ^N^SU^O C60.1, H 6.95, N 4.85%

31 P nmr J H decoupled (CDC1 3 , 162MHz) 6 34.5 and 34.3 ppm

Example 82

Ph

Compound 85 T = 1 - thyminyl)

To a solution of Compound 84 (1.2g, 2.1 mmol) in dry THF (30ml) containing acetone (3.2ml) is added in titanium (TV) isopropoxide (738μl, 2.48 mmol). After 15 minutes, concentration and passage through a shoπ column of silica (eluant ethyl acetate: ethanol 4:1) (500ml) gives Compound 85 isolated as a mixture of 2 diastereoisomeπ.

31 P nmr H decoupled (CDC1 3 , 162MHz) δ 55.0, 54.7 ppm

Found: C 57.7, H 7.05, N 4.05% C 32 H 45 N 2 O 7 PSi.2H 2 O requires C 57.8, H 7.4, N 4.2%

Example 83

Compound 86 I - thyminyl)

C(CH 3 >20H o a solution of Compound 85 (1.02g, 1.62mmol) and acetic acid (92μl, lό.lmmol) in THF OOmI) s added a solution of tetra-n-butyl ammonium fluoride (1.63ml, l.OMolar). After stirring at

room temperature for 1 hour, the mixture is concentrated and co-evaporated with chloroform (50ml). Purification by flash silica column chromatography (eluant chloroform ethanol 9:1) gives Compound 86 isolated as a mixture of two diastereoisomcπ.

Found: C 45.55, H 6.85, N 6.4% C 16 H 27 N 2 θ 7 P.1 . H 2 O requires C 45.7, H 7.25, N 6.6% 31 P nmr H decoupled (CDC1 3 , 162MHz) δ 56.7, 56.5 ppm.

Example 84

= 1 - thyminyl)

To a solution of Compound 86 (550mg, 1.41mmol) in pyridine (10ml) is added dimethoxytrirychloride (958mg, 2.83mmol). After stirring at room temperature for 20 houπ, concentration and purification by flash silica column chromatography (eluant chloroform, methanol, triethylamine 100:5:1) gives Compound 87, isolated as a mixture of 2 diastereoisomers.

31 P nmr ^coupled (CDC1 3 , 162MHz) 6 54.9, 54.7 ppm.

Example 85

• thy iryl)

To a solution of Compound 87 (0.85g, 1.22mmol) in anhydrous methanol (10ml) is added sodium methoxide 0-5ml 4.4N solution in methanol). After stirring for 16 houπ at room temperature, concentration and purification by flash silica column chromatography (gradient elution - chloroform, methanol, triethylamine 100:20:1 - 100:35:1) gives Compound 88 as a white powder.

31 P nmr J H decoupled (CD 3 OD, 162MHz) 623.7 ppm.

Example 86

C(CH 3 )2θH

To a solution of 1,2,4-triazole (69mg, Immole) in anhydrous pyridine (2ml) at 0°C under argon is added triethylamine (300μl, 4mmol) followed by phosphorus oxychloride 08μl, 0.2mmol) dropwise over 2 minutes. To the resulting solution is added Compound 87 (75mg, O.llmmol) in pyridine (0.5ml). After stirring at room temperature for 1 hour, further portions of triethylamine (300μl, 4mmol) and phosphorus oxychloride 08μl, 0.2mmol) are added. After standing at room temperature for 20 houπ, the solution is concentrated, dissolved in chloroform 00ml) and washed with sodium bicarbonate (satd) (5ml). The aqueous phase is reextracted with chloroform 00ml) and the combined organic phase dried over Na 2 SO 4 , filtered and concentrated to give Compound 89 as a mixture of 2 diastereoisomeπ.

31 P nmr *H decoupled (CDC1 3 , 162MHz) δ 55.2, 55.0 ppm.

Example 87

QO OH

Compound 89 (50mg) is dissolved in cone, ammonia solution (5ml). After standing at room temperature for 18 houπ, concentration, co-evaporation with toluene and purification by flash silica column chromatography (gradient elution: ethyl acetate, methanol, triethylamine 100:12:1 100:20:1) gives Compound 90 as a mixture of 2 diastereoisomeπ.

31 P nmr ! H decoupled (CDC1 3 , 162MHz) δ 55.1 55.0 ppm.

Example 88

Compound 91

H

Compound 91 is prepared from Compound 90 using the procedure of Example 85. Purification by flash silica column chromatography (eluant: chloroform, methanol, triethylamine 100:67:1) gives Compound 91 isolated as the triethylamine salt.

31 P nmr l H decoupled (CD 3 OD, 162MHz) 6 23.7 ppm.

Example 89

To a suspension of N-benzoyladenine (59mg, 0.25mmol) in 1,2-dichloroethane (1ml) bistrimethylsilylacetamide (123μl, 0.50mmol) is added. The suspension is heated to 75°C for 0.75 houπ, and the resulting solution is cooled to 20°C To the above a solution of Compound 70 (76mg, O.llmmol) in 1,2-dichloroe thane 0-3ml) is added, followed dropwise by trimethylsilyl trifluoromethanesulphonate (57μl, 0.29mmol). The mixture is stirred at 20°C for 0.25 houπ, then heated to 45-50°C for a period of 8 houπ. The solution is allowed to cool and pyridine (0.5ml) is added. The reaction mixture is evaporated and purified by chromatography on silica gel, eluting with a gradient of ethanol/chloroform. Compound 92, a white solid is obtained as a mixture of diastereoisomers.

31 P nmr (162MHz, CDC1 3 ) δ 52.9, 53.1 ppm m/z (FAB*, thioglycerol) 1025 (MH * )

Example 90

Compound 93 (A = adeninyl)

To a solution of Compound 92 Olmg, llμmol) in methanol (4ml) DBU (50μl) is added, giving an immediate precipitate. After 20 houπ at 20°C the reaction mixture is evaporated and subjected to chromatography on the acid form of a sulphonic acid ion exchange resin, eluting with water then 5% aqueous ammonia. The product collected is further purified by chromatography on an ammonium ion exchange resin, eluting with water. Evaporation of the relevant fractions gives Compound 93 as a white solid.

31 P nmr (162MHz, CDC1 3 ) δ 42.9 ppm

m/z (FAB * , thioglycerol) 593 (MH ÷ -NH 3 )

Example 91

To a suspension of thvmine (0.33g, 2.6mmol) in 1,2 dichloroethane (4ml) bistrimethylsilylacetamide (1.3ml, 5.3mmol) is added The suspension is heated to 65°C for 45 minutes, and the resulting solution is cooled to 20°C A solution of Compound 70 (0.8g, 1.2mmol) in 1,2 dichloroethane (6ml) is added, followed dropwise by trimethylsilyltrifluoromethanesulphonate (0.64ml, 3.3mmol). The mixture is stirred at 20°C for 15 minutes, then heated to 65°C for 2.5 houπ. After cooling, saturated aqueous sodium bicarbonate (10ml) is added slowly. The resulting mixture is extracted with chloroform three times. The combined organic phase is washed with brine, dried over magnesium sulphate and evaporated. The residue is purified by chromatography on silica gei, eluting with ethyl acetate/methanol gradient. Compound 94, a white solid, is obtained as a mixture of diastereoisomers.

31 P nmr (162MHz, CDC1 3 ) δ 54.0, 54.2 ppm m/z (FAB * , thioglycerol) 799 (MH * )

Example 92

Compound 95 (T = 1 - thyminyl)

To a solution of Compound 94 (200mg, 0.25mmol) in methanol (7ml) DBU (50μl) is added. After 15 houπ at 20°C, a further amount of DBU is added (200μl). After 4 houπ, the reaction mixture is evaporated and the residue is purified on a sulphonic acid ion exchange resin, eluting with water. Compound 95 is obtained as a white solid after lyophilization.

31 P nmr (162MHz, D 2 O) δ 55.2 ppm m/z (FAB + , thioglycerol) 575 (MH * ) 597 (MNV)

Example 93

Compound 96 H (A = adeninyl)

NH 3 .

A solution of Compound 28 (202mg, 0.264 mmol) in a mixture of acetic acid, water and THF (1:1:4, 6ml) is heated to 55-60°C for 6 houπ, then evaporated to give crude Compound 29. The latter (0.18g) is dissolved in methanol (7ml) and DBU (0.19ml, 1.32mmol) is added. After 1.75houπ the solvent is evaporated The residue is passed down a column of Dowex - 50W X -2 H* from ion exchange resin, and product - containing fractions pooled and evaporated. The residue is dissolved in aqueous ammonia and stood at 20°C for 3 days, after which time it is evaporated and purified by ion exchange chromatography fiπt using a H* form coiumn, and then an ammonium ion exchange resin. Compound 96 is obtained as a white solid after freeze-drying.

31 P nmr (D 2 0, 161MHz) 6 26.1 ppm.

Example 94

1 - thyminyl)

To a solution of Compound 87 (780mg, 1.12mmol) in dry dichloromethane (5ml) is added bis(trimethylsilyl) trifluoroacetamide 0-5ml, 5.65 mmol). The resulting mixture is stirred at room temperature for 2.5 houπ, stood at 5°C for 60 houπ and stirred for a further 18 houπ at room temperature. Concentration and purification by flash silica column chromatography (eluant 200:4:1 ethyl acetate: ethanol: triethylamine) gives a thick oil. Dissolution in dichloromethane, washing with water and drying (Na SO 4 ) then gives Compound 97, isolated as a mixture of two diastereoisomeπ. 31 P nmr l H decoupled (CDC1 3 , 162MHz) 654.1, 54.0 ppm.

Example 95

To a solution of 1,2,4-triazole 096m , 2.84mmoI) in anhydrous pyridine (4ml) at 0°C under argon is added triethylamine (1.25ml, 9mmol) followed by phosphorus oxychloride (66μl, 0.71 mmol) dropwise over 1 minute. The resulting solution is stirred at 0-5°C for 5 minutes. To this solution is added a solution of Compound 97 (217mg, 0.284mmol) in anhydrous pyridine (2+2ml) dropwise over 2 minutes. The resulting mixture is stirred at 0-5°C for 10 minutes and stood at room temperature for 16 houπ. The solution obtained is concentrated dissolved in dichloromethane (30ml) and washed with saturated aqueous sodium bicarbonate. The aqueous phase is re-extracted with dichloromethane and the combined organic phase dried over Na 2 SO 4 , filtered and concentrated to give Compound 98 as a mixture of 2 diastereoisomeπ.

31 Pnmr ! H decoupled (CDC1 3 , 162MHz) 554.2, 53.8ppm.

Example 96

Compound 99 is prepared from Compound 98 by the method of Example 87. Purification by flash silica column chromatography (gradient elution : dichloromethane : ethanol : triethylamine 200: 13: 1 - 200:20: 1) followed by further flash silica column chromatography (gradient elution : ethyi acetate : ethanol : triethylamine 200:13:1 - 200:70:1) gives Compound 99 as a mixture of 2 diastereoisomeπ.

31 P nmr l U decoupled (CDC1 3 , 162MHz) 654.3, 54.1 ppm.

Example 97

A solution of Compound 99 (470mg, O.όlmmol) in methanol (10 ml) containing DBU (0.46ml) is heated at 60°C for 3 houπ. Concentration, dissolution in wateπtriethylamine (200:1) and passing through a Dowex 50W x 2 column presarurated with triethylamine gives on elution with water/triethylamine (200:1) Compound 91 isolated as the triethylamine salt

Example 98

To a solution of Compound 91 (420mg, 0.59mmol) in methanol 00ml) containing triethylamine (0.17ml, I.22mmol) is added N-methylpyrolidone dimethvlether (0.43ml, 2.97mmol). After standing at room temperature for 18 hours, a further portion of the ether is added (0.20ml, 1.38mmol) and the mixture is stirred for a further 3 houπ. Concentration and purification by flash silica column chromatography (chloroform:me_hanol:triethylamine 200:60:1) gives Compound 100 as a white foam.

31 P nmr ! H decoupled (CD 3 OD, 162MHz) 6 23.7ppm.

Example 99

Compound 101 phenyl T = 1 -dvymmyi)

A solution of Compound 84 (0.78g, 1.37mmol) in ethanol (2.7ml), water (1.4ml) and triethylamine (2.7ml) is stined at room temperature. After 3 hours, the reaction mixture is diluted with ethyl acetate (25ml), and washed successively with 0.05M aqueous HCl 0 x 10ml) and water (1 x 10ml). The organic extract is dried over magnesium sulphate and evaporated to give Compound 101 as a clear colourless viscous oil.

31 P (162MHz, CDC1 3 ) 635.47ppm.

Example 100

Compound 102 1 -thyminyl)

Dicyclohexylcarbodiimide (109mg, 530μmol) is added to a solution of Compound 101 (230mg, 424μmol) and 2,6-dimethyl-4-amino pyridine (0.6mg, 5μmoI) in methanol (21.5μl, 530μmol) and tetrahydrofuran (4.2ml) at 0°C After stirring for 4 houπ at room temperature, the reaction mixture is filtered and then evaporated

Flash column chromatography of the evaporation residue on silica, eluting with 95% ethyl acetate, 5% methanol gives Compound 102 as a viscous clear colourless oil.

31 P (162MHz, CDC1 3 ) 6 37.32, 37.08ppm.

Example 101

Compound 103 T = 1 -thyminyl)

Dicyclohexylcarbodiimide (104mg, 506μmol) is added to a solution of Compound 101 (220mg, 405μmol) and 2-cyanoethanol (35μl, 506μmol) in tetrahydrofuran (4.1ml) at 0°C After stirring for 4 houπ at room temperature, the reaction mixture is filtered and evaporated to give Compound 103 as a viscous clear colourless oil.

31 P (162MHz, CDC1 3 ) 537.79, 37.54ppm.

Example 102

Benzyl chloromethyl ether 073μl, l.lmmol) is added dropwise to a solution of Compound 83 (380mg, 553μmol) and l,8-diazabicyclo[5.4.0]undec-7-ene. (DBU) (145μl, 968μmol) in acetonitrile (11 ml) at 0°C After stirring for 2 houπ at room temperature, saturated aqueous sodium hydrogen carbonate (20ml) is added and the aqueous layer extracted with (3 x 20ml) ethyl acetate. Drying of the organic extracts over magnesium sulphate and evaporation yields

the crude product. Purification via flash column chromatography on silica, eluting with 98% dichloromethane. 2% methanol, gives Compound 104 as a viscous clear colourless oil.

Example 103

Compound 105 = N-benzyloxymeιhyl-1-thymιnyl)

Trime-hylchlorosilane (613μl, 4.83mmol) is added dropwise at 0°C to a solution of Compound

104 in chloroform containing ethanol 00%) under argon. After stirring for 18 houπ at room temperature, saturated aqueous sodium hydrogen carbonate (20ml) is added, the aqueous layer is extracted with dichloromethane 0 x 20, 2 x 10ml) and the organic extracts dried over magnesium sulphate. Evaporation gives the crude product which is purified by flash column chromatography on silica, eluting with 95% dichloromethane, 5% methanol, to give Compound

105 as a viscous clear colourless oil-

Example 104

Compound 106

(CHVnC _» N-benzyloxymethyl-l-thyminyl)

A solution of Compound 105 (0.29g, 420μmol) in ethanol (1.7ml), water (0.8ml) and triethylamine (1.7ml) is stirred at room temperature for 4 houπ. After dilution with ethyl acetate (30ml), the reaction mixture is washed with cold 0.05 M aqueous HCl (2 x 20ml), then water (2

x 20ml) and dried over magnesium sulphate. Evaporation yields Compound 106 as a viscous clear colourless oil.

31 P (162MHz, CDC1 3 ) 635.62ppm.

Example 105

Compound 107

(CH 3 )3C • N-beπzyloxymethyl-l-thyminyl)

Dicyclohexylcarbodiimide (105mg, 509μmol) is added to a solution of Compound 106 (270mg, 407μmol), 2,6-dimethyI-4-aminopyridiπe (0.6mg, 5μmol) and methanol (21μl, 509μmol) in tetrahydrofuran (4.1ml) at 0°C After stirring for 3 hours at room temperature, the reaction mixnire is evaporated Flash column chromatography of the evaporation residue on silica, eluting with 95% ethyl acetate, 5% methanol yields Compound 107 as a viscous clear colourless oil.

31 P (162MHz, CDC1 3 ) 637.37, 37.08 ppm.