Hypophosphorous acid derivatives and their therapeutical applications

The invention relates to hypophosphorous acid derivatives having agonist or antagonist properties for metabotropic glutamate receptors (mGluRs), in particular agonist or antagonist properties for group III, subtype 4, metabotropic glutamate receptors (mGlu4Rs) and their therapeutical applications.

MGluRs are of particular interest in medicinal chemistry because they are believed to be suitable targets for treating a large variety of brain disorders such as convulsions, pain, drug addiction, anxiety disorders, and several neurodegenerative diseases.

The eight known subtypes of mGluRs are classified into three groups. Group III contains subtypes 4 and 6-8. Mainly located presynaptically, where they act as autoreceptors, group III mGluRs decrease adenylyl cyclase activity via a Gy ₁ Q protein and are specifically activated by L-AP4. Among this group, mGlu4R is thought to be a possible new target for Parkinson's disease, but the lack of a highly specific agonist has seriously impaired target validation studies. Furthermore, despite many chemical variations around the structure of glutamate, L-AP4 remains the strongest mGlu4R agonist with an ECs ₀ of only 0.32 μM and its α-methyl analogue, a competitive antagonist with an IC ₅₀ of lOOμm. New chemotypes of higher potency and specificity are to be found.

The inventors' researches in that field lead them to develop methods of synthesis of hypophosphorous acids making it possible to obtain a large number of valuable agonists or antagonists for mGlu4Rs, particularly analogs of 3-ammo-carboxy-propyl-2'-carboxy- ethylphosphinic acid (PCEP in short), with improved activity and selectivity compared to PCEP and valuable antagonists corresponding to the α-substituted derivatives thereof.

An object of the invention is then to provide new hypophosphorous acid derivatives, particularly having agonist or antagonist properties for group III mGluRs.

Another object of the invention is to provide new methods of synthesis of biologically active hypophosphorous acid derivatives with a large variety of substituents.

According to still another object, the invention takes advantage of the mGlu4Rs agonists or antagonist properties of the hypophosphorous acid derivatives thus obtained and aims to provide pharmaceutical compositions useful for treating brain disorders.

The hypophosphorous acid derivatives of the invention are diasteroisomers or enantiomers of formula (I)

wherein

. M is a [C(R ₃ ,R ₄ )],, _! - C,(E,COOR ₁ , N(H, Z)) group, or an optionally substituted Ar-CE,(COOR ₁ , N(H, Z)) group (Ar designating an aryl or an heteroaryl group), or an α, β cyclic aminoacid group such as ,

or a β, γ-cyclic aminoacid group such as

-C(E ₁ COOR ₁ , N(H, Z)) . R ₁ is H or R, R being an hydroxy or a carboxy protecting group, such as C ₁ -C ₃ alkyl, Ar (being aryl or heteroaryl),

. Z is H or an amino protecting group R% such as C ₁ -C ₃ alkyl, C ₁ -C ₃ acyl, Boc, Fmoc, COOR, benzyl oxycarbonyl, benzyl or benzyl substituted such as defined with respect to Ar; .E is H or a C1-C3 alkyl, aryl, an hydrophobic group such as (CH2) _n i -alkyl, (CH ₂ ) _n i-aryl (or heteroaryl), such as a benzyl group, or a xanthyl, alkyl xanthyl or alkyl thioxanthyl group, or - (CH ₂ ) _n i-cycloalkyl, -(CH ₂ ) _n -(CH2-Ar) ₂ , a chromanyl group, particularly 4-methyl chromanyle, indanyle, tetrahydro naphtyl, particularly methyl-tetrahydronaphtyl ; R ₂ is selected in the group comprising: D-CH(R ₆ )- C-(R ₇ , R ₈ ) - (R ₁₁ ,R ₁₂ )CH- C(R ₉ , R ₁₀ ) - D - CH(OH) - D- [C(R ₁₃ , Ru)]n3 -

C[(R ₁₅ , R ₁₆ , Rl ₇ )]n4 -

D-CH ₂ -

(R ₁₈ )CH = C(R ₁₉ ) -

PO(OH) ₂ -CH ₂ or (PO(OH) ₂ -CH ₂ ), (COOH-CH ₂ )-CH ₂ - with

- D = H, OH, OR, (CH ₂ ) _n2 OH, (CH ₂ ) _nl OR, COOH, COOR, (CH ₂ ) _n2 COOH, (CH ₂ ) _nl COOR,

SR, S(OR), SO ₂ R, NO ₂ , heteroaryl, C ₁ -C ₃ alkyl, cycloalkyl, heterocycloalkyl, (CH ₂ ) _n2 -alkyl,

(COOH, NH ₂ )-(CH ₂ ) _ul -cyclopropyl-(CH ₂ ) _u2 -, CO-NH-alkyl, Ar, (CH ₂ ) _n2 -Ar, CO-NH-Ar, R being as above defined and Ar being an optionally substituted aryl or heteroaryl group,

- R ₃ to R ₁₉ , identical or different, being H, OH, OR, (CH ₂ ) _n2 OH, (CH ₂ ) _nl OR, COOH, COOR, (CH ₂ ) _n2 COOH, (CH ₂ ) _nl C00R, C ₁ -C ₃ alkyl, cycloalkyl, (CH ₂ ) _nl -alkyl, aryl, (CH ₂ ) _nl -aryl,

halogen, CF ₃ , SO ₃ H, (CH ₂ ) _X PO ₃ H ₂ , with x = 0, 1 or 2, B(OH) ₂ , , NO ₂ , SO ₂ NH ₂ ,

SO ₂ NHR; SR, S(O)R, SO ₂ R, benzyl; one Of R ₁₁ or R ₁₂ being COOR, COOH, (CH ₂ )n ₂ -COOH, (CH ₂ )n ₂ -COOR, PO ₃ H ₂ the other one being such as defined for R ₉ and R ₁₀ ;

- one ofR ₁₅ , R ₁₆ and R ₁₇ is COOH or COOR, the others, identical or different, being such as above defined;

- one of R ₁₈ and R ₁₉ is COOH or COOR , the other being such as above defined;

- Mi is an alkylene or arylene group; - nl= 1, 2 or 3;

- n2= 1, 2 or 3, - n3= 0, 1, 2 or 3 and - n4= l, 2 or 3; - n5= l,2 or 3; - n6= 0 or 1,

- ul and u2, identical or different = 0,1 or 2,

Ar, and alkyl groups being optionally substituted by one or several substituents on a same position or on different positions, said substituents being selected in the group comprising: OH, OR, (CH ₂ ) _n i0H, (CH ₂ )m0R, COOH, COOR, (CH ₂ ) _nl C00H, (CH ₂ ) _n iC00R, C ₁ -C ₃

alkyl, cycloalkyl, (CH ₂ ) _n i-alkyl, aryl, (CH ₂ ) _n i-aryl, halogen, CF ₃ , SO ₃ H, (CH ₂ ) _X PO ₃ H _2, with

x , NO ₂ , SO ₂ NH ₂ , SO ₂ NHR; SR, S(O)R, SO ₂ R, benzyl;

R being such as above defined, with the proviso that formula I does not represent the racemic (3R, S) and the enantiomeric form (3R) of 3 amino,3-carboxy-propyl-2'-carboxy-ethylphosphinic acid; 3 amino,3-carboxy- propyl- 4'carboxy,2'carboxy-butanoylphosphinic acid; 3 amino^-carboxy-propyl- 2'carboxy- butanoylphosphinic acid; 3 amino,3-carboxy-propyl- 3'amino, 3'carboxy-propylylphosphinic acid; and 3 amino,3-carboxypropyl -7'amino-2', T'-dicarboxyheptylphosphinic acid..

In the above defined hypophosphorous acid derivatives of the invention, D is preferably Ar (optionally substituted), Ar-(CH ₂ ) _n2 (with Ar optionally substituted), C ₁ -C ₃ alkyl or cycloalkyl ; alkyl - (CH ₂ ) _n 2, or COOH. Preferably Ar is a phenyl group (optionally substituted) or a carboxyalkyl group (optionally substituted). Alternatively, Ar is an heterocyclic group (optionally substituted). Advantageous groups are thiophenyl or furanyl group (optionally substituted).

A first preferred family corresponds to hypophosphorous acid derivatives of formula (II)

D-CH(R ₆ ) — C-(R ₇ ,

wherein the substituents are as above defined.

In particularly preferred derivatives of this family, D is Ar or a substituted Ar, especially a phenyl group optionally substituted by 1 to 5 substituents. The substituents are in ortho and/or meta and/or para positions. Preferred substituents comprise: OH, OR, (CH ₂ ) _n2 θH, (CH ₂ ) _n2 OR, COOH, COOR, (CH ₂ )^COOH, (CH ₂ )^COOR, C1-C3 alkyl or cycloalkyl, (CH ₂ ) _n2 -alkyl, aryl, (CH ₂ ) _n2 -aryl, halogen, CF ₃ , SO ₃ H, PO ₃ H ₂ , B(OH) ₂ alkylamino, fluorescent

group (dansyl, benzoyl dinitro 3, 5', , NO ₂ , SO ₂ NH ₂ , SO ₂ (NH,R) SR, S(O)R,

SO ₂ R, OCF ₃ , heterocycle, heteroaryl, substituted such as above defined with respect to Ar.

δHvantaσpnnsiv R^ anH/nr R-, anrl/nr Ro are H C. ,.CA nilrvi ON f!F, NRo

wherein the substituents are as above defined.

In preferred derivatives, one of R ₁₁ or R ₁₂ is COOH.

Advantageously, the other one Of R ₁₁ or R ₁₂ , and/or R ₉ and/or R ₁₀ are H, C ₁ -C ₃ alkyl, OH,

NH ₂ , CF ₃ .

A third preferred family corresponds to hypophosphorous acid derivatives of formula (IV)

wherein the substituents are as above defined.

In preferred derivatives, D is as above defined with respect to formula (II)

In a fourth preferred family, the hypophosphorous acid derivatives have formula (V)

wherein the substituents are as above defined, one of R^ or R ₁₄ representing OH.

In preferred derivatives, D is as above defined with respect to formula (II).

The substituent R ₁₃ or R ₁₄ which does not represent OH is advantageously H, C ₁ -C ₃ alkyl,

OH, CF ₃ , NH ₂ .

In a fifth preferred family, the hypophosphorous acid derivatives have formula (VI)

wherein the substituents are as above defined.

In preferred derivatives, in the first group of the chain, one or two of R ₁₅ , R ₁₆ or R ₁₇ are

COOH, the other(s) advantageously being H. Ci-Gi alkvl. OH. NH? CF,

(VII) wherein the substituents are as above defined.

In preferred derivatives, D is as above defined with respect to formula (II).

In a seventh family, the hypophosphorous acid derivatives have formula (VIII)

(VIII) wherein the substituents are as above defined.

In preferred derivatives, R _1S is COOH.

Advantageously, R ₁₉ is H, C ₁ -C ₃ alkyl, OH.

An eighth family corresponds to hypophosporous acid derivatives of formula (LIX)

(LK) wherein the substituents are as above defined.

In preferred derivatives, either n6= O, or n6= 1 and Mi is an alkylene or arylene group such as above defined.

In a preferred embodiment of the invention, M is a [C(Ra,R ₄ )J _n I -C (E, COOR ₁ , N (H,Z)) group, in the above defined hypophosphorous acid derivatives. Preferably R ₃ and/or R ₄ are H and nl=l or 2, more preferably 2.

In another preferred embodiment, M is an Ar group or a substituted arylene group, particularly a C ₆ H ₄ group or a substituted C ₆ H ₄ group, the substituents being as above defined with respect to formula I.

In still another embodiment, M comprises a cyclic aminoacid group, particularly, M is an α, β

cyclic aminoacid group such as or a β, γ-cyclic aminoacid group such as

-C(E, COOR ₁ , N(H, Z))

The invention particularly relates to the above mentioned derivatives wherein E represents H, which are group III mGluR agonists, and more particularly mGlu4R agonists of great interest.

The invention also particularly relates to the above mentioned derivatives wherein E is different from H and is more especially a C1-C3, alkyl, an aryl, an hydrophobic group such as a (CHb) _nI - alkyl group, or a (CH2) _n i-aryl group, as above defined, particularly a benzyl group, or a methylxanthyl group or alkylxanthyl or alkylthioxanthyl.

Advantageously, such derivatives are valuable mGluR antagonists, particularly mGlu4 antagonists.

The invention also relates to a process for preparing hypophosphorous acid derivatives of formula I

wherein the substituents are as above defined.

According to method A), said process comprises al) treating a derivative of formula (IX)

with either trimethylsilylchloride (TMSCl) and triethylamine (Et3N), or N,O-(bis- triethylsilyl)acetamide (BSA), (Et representing a C ₂ H ₅ group). a2) adding to the reaction product one of the following derivatives having, respectively, formula X: D-C(R ₆ ) = C(R ₇ , R ₈ ), or formula XI: (R ₁₁ ,R ₁₂ )C= C(R ₉ , R ₁₀ ) formula XII:

formula XIII: D - CH(=O) formula XIV: D- [C(R ₁₃ , R ₁₄ )] _n3 - Br formula XV: [C(R ₁₅ , R ₁₆ , R ₁₇ )] _n4 - Br formula XVL- D - 1 formula XVII: (R ₁₈ )C ≡ C(R ₁₉ ) a3) treating the reaction product under acidic conditions or with catalysts to obtain the final desired product; a4) recovering the diastereoisomers or the enantiomer forms, a5) if desired, separating diastereoisomers, when obtained, into the enantiomers.

According to method B, said process comprises b 1 ) treating a derivative of formula (XVIII)

(R"SiO) ₂ - P-H

(XVIII) wherein R" is a C ₁ -C ₃ alkyl . with either a derivative of formula (X)

D - C (R ₆ ) = C(R ₇ , R ₈ ) (X)

or with a derivative of formula (XI)

(R _{1 1} ,R ₁₂ )C= C(R ₉ , R ₁₀ ) (XI)

wherein one of R ₉ or R ₁₀ is COOaIk, alk being a C ₁ -C ₃ alkyl b2) treating the condensation product with a dibromo derivative of formula (XIX)

(XIX) under reflux conditions; and adding HC(OaIk) ₃

wherein alk is a C1-C3 alkyl b3) treating the condensation product with a derivative of formula (XX)

NH(Z)-CH(CO ₂ R) ₂

(XX)

in the presence of K ₄ CO ₃ , BuO ₄ NBr, under reflux conditions;

b4) treating the condensation product under acidic conditions or with catalyts to obtain the final desired product; b5) recovering the diastereoisomers or the enantiomer forms, and b6) if desired, separating diastereoisomers, when obtained, into the enantiomers.

Alternatively, the reaction product obtained at step bl) is reacted according to step b2i), with a derivative of formula (XXI)

[(R ₃ , R ₄ )CJ _n1 = C (COOR ₁ , NH(Z))

(XXI)

In step b3i), the reaction product is treated under acidic conditions to give the final desired product.

According to method C, said process comprises cl) reacting, as defined in step al), a derivative of formula (XXII)

wherein Ar is as above defined and preferably an optionally substituted C ₆ H ₄ group and T CA) carrying oux reacπon step azj oy using one or me derivatives oi rormula (X; to (AVHj

c3) treating the reaction product with NBS, AIBN to have bromo derivatives with Ar substituted by T'-Br, with T'= CH ₂ c4) reacting the bromo derivative thus obtained with (CH) ₆ N ₄ in an organic solvent, then AcOHZH ₂ O to obtain cetone derivatives with Ar substituted by-C=O; c5) treating the cetone derivatives with KCN, NH ₄ Cl and NH ₄ OH to obtain aminocyano derivatives, with Ar substituted by -C (CN, NH ₂ ), c6) treating under acidic conditions to obtain derivatives with Ar substituted by -C (COOR, NH ₂ ), and c7) treating with catalysts to obtain the final desired product. In method A, according to a preferred embodiment . the use of derivatives of formula (X)

D-CH(R ₆ )=C(R ₇ , R ₈ ) _rø

with derivatives of formula (IX) results, in step a2), in intermediate derivatives of formula (XXIII)

D-CH(R ₆ )-C(R ₇ , R ₄ ) iJ-CH(COOR ₁ , NH(Z))

(XXIII)

and, in step a3), in a final product of formula (XXIV)

D-CH(R ₆ )-C(R _7> R ₄ ) iJ-CH(COOH, NH ₂ )

(XXIV)

the use of derivatives of formula (XI) or formula (XII)

(R _π ,R ₁₂ )C= C(R ₉ , R ₁ o)

(XI)

(XII)

results, in step a2), in intermediate derivatives of formula (XXV)

O

(R ₁₁ , R ₁₂ )CH-(R ₉ , R ₁₀ )C-P [C(R ₃ , R ₄ )J-CH(COOR ₁ , NH(Z))

(XXV) and, in step a3), in a final product of formula (XXVI)

O

(R ₁₁ , R ₁₂ )CH-(R ₉ , R ₁₀ )C-P [C(R ₃ , R ₄ )J-CH(COOH, NH ₂ )

(XXVI)

. the use of derivatives of formula (XIII)

D-CH (=0)

(XIII) results, in step a2), in intermediate derivatives of formula (XXVII)

R ₄ )J-CH(COOR ₁ , NH(Z))

(XXVII)

and, in step a3), in a final product of formula (XXVIII)

R ₄ )J-CH(COOH, NH ₂ )

CXXVIID

. the use of derivatives of formula (XIV)

D- [C(R ₁₃ , R] ₄ )]n ₃ - Br

(XIV)

results, in step a2), in intermediate derivatives of formula (XXIX)

D-[C(R ₁₃ , R ₄ )J-CH(COOR ₁ , NH(Z))

(XXIX)

and, in step a3), in a final product of formula (XXX)

O

D-[C(R ₁₃ , R ₁₄ )]- P-[C(R ₃ , R ₄ )J-CH(COOH, NH ₂ )

(XXX) . the use of derivatives of formula (XV)

[C(R ₁₅ , R ₁₆ , RnXU - Br

(XV)

results, in step a3), in intermediate derivatives of formula (XXXI)

C(R ₁₅ , R ₁₆ , R ₄ )J-CH(COOR ₁ , NH(Z))

(XXXI)

and, in step a3), in a final product of formula (XXXII)

O

C(R ₁₅ , R ₁₆ , R ₁₇ )- -P— [C(R ₃ , R ₄ )]-CH(COOH, NH ₂ ) n4

. the use of derivatives of formula (XVI)

D-I

(XVI) results, in step a2), in intermediate derivatives of formula (XXXIII)

R ₄ )J-CH(COOR ₁ , NH(Z))

(XXXIII)

.and, step a3), in a final product of formula (XXXIV)

(XXXIV)

. the use of derivatives of formula (XVII)

(R ₁₈ )C=C(R ₁₉ )

(XVII)

results, in step a2), in intermediate derivatives of formula (XXXV)

(XXXV)

and, in step a3), in a final product of formula (XXXVI)

(XXXVI)

. the use of derivatives of formula (LIX)

NH

(LIX) wherein M ₁ is as above defined with respect to M and n6= O or 1 , and results by oxidation in a product of formula (LXI)

NH ₂ )

(LXI)

In method B,

. the use, with derivatives of formula (XVIII),

(R ⁵⁵ SiO) ₂ - P-H

(XVIII) of derivatives of formula (X)

D—CH(R ₆ )—C(R ₇ , R ₈ )

(X)

results, in step bl), in intermediate derivatives of formula (XXXVII)

D-CH(R ₆ )-C (R ₇ ,R ₈ )-P-(OSiR ⁵⁵ ) ₂

(XXXVII)

in step b2), in intermediate derivatives of formula (XXXVIII)

D-CH(R ₆ )-C(R ₇ , R ₄ )J-Br πnrxvrm

in step b3), in intermediate derivatives of formula (XXXIX)

D-CH(R ₆ )-C(R ₇ , R

(XXXIX)

and, in step b4), in a final product of formula (XXXX)

. the use, with derivatives of formula (XVIII), of derivatives of formula (XI)

(R ₁₁ ,R ₁₂ )C= C(R ₉ , R ₁₀ ) (XI)

results, in step bl), in intermediate derivatives of formula (XXXXI)

(R ₁₁ , R ₁₂ )CH-C(R ₉ , R ₁ Q)-P-(OSi R") ₂

(XXXXI) in step b2), in intermediate derivatives of formula (XXXXII)

(R ₁₁ , R ₁₂ )CH-C(R ₉₁ r (XXXXII)

in step b3), in intermediate derivatives of formula (XXXXIII)

(R ₁₁ , R ₁₂ )CH-C(R ₉ , ππππrπτ\

in step b4), in final products of formula (XXXXIV)

(R ₁₁ , R ₁₂ )CH-CH-C(R ₉ , NH ₂ )

(XXXXIV)

or, alternatively,

. the use with derivatives of formula (XXXXI) obtained according to step bl)

(R ₁₁ , R ₁₂ )CH-C(R ₉ , R ₁ Q)-P-(OSi R") ₂

(XXXXI) of derivatives of formula (XXXXV)

(R ₃ , R ₄ ) C =C (COOR ₁ , NH(Z)

(XXXXV) results in intermediate derivatives of formula (XXXXVI)

(R ₁₁ , R ₁₂ )CH-C(R ₉ , C(COOR, NHZ)

(XXXXVI)

the treatment under acidic conditions giving the final product of formula (XXXXVII)

(R ₁₁ , (COOH, NH ₂ )

(XXXXVII)

In method C, the use, of a derivative of formula (XXII),

with a derivative of

formula X: D-C(R ₆ ) = C(R ₇ , R ₈ ), or formula XI: (Rn,Rn)C= C(R ₉ , R ₁₀ ) formula XII:

formula XIII: D - CH(=O) formula XIV: D- [C(R ₁₃ , R ₁₄ )] _n3 - Br formula XV: [C(R ₁₅ , R ₁₆ , Rπ∑U - Br formula XVI: D - I formula XVII: (R ₁₈ )C s C (R ₁₉ )

results in intermediate derivatives respectively having formulae (XXXXVIII) to (LIV)

D-CH(R ₆ )- C-(R ₇ ,

(XXXXVIII)

O

(R ₁₁ , R ₁₂ )CH-C(R ₉ , R ₁₀ )- P Ar-T

(D

(LI)

(LII)

(LIII)

(LIV)

ves of formula IX

(IX)

(LV) with a derivative of formula LVI

(R ₃ , R ₄ ) _H iC=CH-C(E,COOR ₁ , NH(Z))

(LVI)

Preferably, the derivative of formula (LVI) is Z-vinyl-glyOMe or a derivative thereof with E different from H, E being as above defined, and has formula (LVIa).

MeCyO

LE Cbz = carbobenzoxy

CbzN-^S H Il

Cbz-L-α-alkylvlnylglycine methyl ester

Z-vinyl-glyOMe is advantageously synthesized from methionine or glutamate according to references (1), (2) or (3).

Z-vinyl-glyOMe derivatives with E different from H can be prepared from α-alkyl methionine or alpha alkyl glutamate (see reference 4). Alpha amino acids can be stereoselectively α- alkylated using imidazolinones or oxazolidinones (references 5 and 6).

Other methods for obtaining Z-vinyl-glyOMe derivatives are given in Example 9. The reaction is advantageously carried out in the presence of AIBN by heating above 5O ⁰ C - 10O ⁰ C, preferably at about 80 ⁰ C.

In method B, the derivatives of formula (XVIII)

(R"SiO) ₂ - P-H

(XVIII) are advantageously obtained by reacting an hypophosphorous acid ammonium salt of formula (LVII)

O

Il

H— P— H

O ^" NH ₄ ⁺

(LVII) with a disilazane derivative of formula (LVIII)

(alk ₃ Si) ₂ -NH

(LVIII)

The reaction is advantageously carried out under an inert gas, by heating above 100 ⁰ C, particularly at about 120 ⁰ C, or by reacting hypophosphorous acid with N,O-(bis-triethylsilyl)acetamide (BSA) at room temperature. In method C, the derivatives of formula (XXII)

(XXII) are advantageously obtained by reacting a mixture of H ₃ PO ₂ , Ar-NH ₂ , Ar-Br and a catalyst Pd(O) Ln. (Ln=n ligands).

According to method D, intermediate derivatives of formula

are prepared as disclosed in example 8.

The hypophosphorous acid derivatives which are intermediates in the above disclosed process, enter into the scope of the invention.

As above mentioned, said hypophosphorous acid derivatives have mGluRs agonist or antagonist properties of great interest and therefore are particularly valuable as active principles in pharmaceutical compositions to treat brain disorders.

They are particularly mGlu4Rs agonists or antagonists of great value.

The invention thus also relates to pharmaceutical compositions, comprising a therapeutically effective amount of at least one of the hypophosphorous acid derivatives of formula I in combination with a pharmaceutically acceptable carrier.

The invention also relates to the use of at least one of hypophosphorous acid derivatives of formula I for preparing a drug for treating brain disorders.

The pharmaceutical compositions and drugs of the invention are under a form suitable for an administration by the oral or injectable route.

For an administration by the oral route, compressed tablets, pills, capsules are particularly used. These compositions advantageously comprise 1 to 100 mg of active principle per dose unit, preferably 2.5 to 50 mg.

Other forms of administration include injectable solutions for the intravenous, subcutaneous or intramuscular route, formulated from sterile or sterilizable solution. They can also be suspensions or emulsions.

These injectable forms, for example, comprise 0.5 to 50 mg of active principle, preferably 1 to 30 mg per dose unit.

The pharmaceutical compositions of the invention prepared according to the invention are useful for treating convulsions, pain, drug addiction, anxiety disorders and neurodegenerative diseases.

By way of indication, the dosage which can be used for treating a patient in need thereof, for example, corresponds to doses of 10 to 100/mg/day, preferably 20 to 50 mg/day, administered in one or more doses.

The conditioning with respect to sale, in particular labelling and instructions for use, and advantageously packaging, are formulated as a function of the intended therapeutic use.

According to another object, the invention relates to a method for treating brain disorders, comprising administering to a patient in need thereof an effective amount of an hypophosphorous acid derivative such as above defined.

According to still another object, the invention relates to the use of at least one hypophosphorous acid derivative such as above defined for preparing a drug for treating drug disorders.

Other characteristics and advantages of the invention will be given in the following examples illustrating the synthesis of hypophosphorous acid derivatives. In the examples, it

- IE: mGlu4 activation inhibition by DCG-IV by (3U)-PCEP

Experimental section:

Example 1: Synthesis of hypophosphorous acid derivatives according to Method A

Scheme 1

Reagents and conditions: (a) AIBN, CH ₃ OH, reflux at 80°C, 5h; (b) TMSCl, Et ₃ N; (c) ethyl acrylate, 6h; (d) 8N

HCl, reflux

(3S)-3-[((3-(iV-Benzyloxycarbonyl)amino-3-methoxycarbonyl)pr opyl)(hydroxy)phosphinyl] propanoic Acid Ethyl Ester (6). The compound 5 (180mg, 0.57mmol) was treated with a mixture of trimethylsilylchloride (TMSCl, 130.4mg, 1.2mmol)/ triethylamine (Et ₃ N, 121mg, 1.2mmol) in dichloromethane at 0°C , then stirred at room temperature for one hour under a argon atmosphere. Then again cooled to 0°C and ethyl acrylate was carefully added dropwise. The mixture was stirred at room temperature for 6h. The reaction mixture was treated with IN HCl and extracted with ethylacetate. The organic layer was dried over MgSO ₄ and evaporated under vacuum to give 6 (130mg, 55% yield). ¹ H NMR (CD ₃ OD): δ 1.26 (t, J= 7.0 Hz, 3H), 2.01 (m, 6H), 2.60 (m, 2H), 3.73 (s, 3H), 4.15 (q, J= 7.0 Hz, 2H), 4.29 (m, IH), 5.12(s, 2H), 7.34(m, 5H). ³¹ P NMR (CD ₃ OD): δ 53.6.

(3S)-3-[((3-Amino-3-carboxy)propyl)(hydroxy)phosphinyl]pr opanoic Acid (7). A solution of 6 (130mg, 0.31mmol) in 6N HCl was refluxed overnight and the solution was evaporated

NMR (D ₂ O): δ 1.69 (m, 2H), 1.89 (m, 2H), 2.08 (m, 2H), 2.55 (m, 2H), 4.00 (t, J= 5.9 Hz, IH). ³¹ P NMR (D ₂ O): δ 57.4. [α] _D +12.8° (c 1.0, H ₂ O) (lit. [α] _D +12.5° (c 1.2, H ₂ O), Ragulin e/ α/., JP-2001-213887) . Scheme 2

17 20

Reagents and conditions: (a) diethylglutaconate, CH ₂ CI ₂ , BSA, 15h; (b) 6N HCl, reflux; (c) dimethylitaconate,

CH ₂ Cl ₂ , BSA, 15h; (d) 6N HCl, reflux

Scheme 2a, 2b

(3iS)-3-[(((3-(iV-BenzyIoxycarbonyl)amino-3- methoxycarbonyl)propyl)(hydroxy)phosphinyl) -methyl] pentane-l,5-dioic Acid Diethyl Ester (15). To a solution of 5 (O.δramol) and diethylglutaconate (558mg, 3mmol) in 2 ml of methylene chloride at O ⁰ C under an argon atmosphere was added dropwise N,O-(bis-triethysilyl)acetamide (BSA) (1.49ml, βmmol). The mixture was allowed to warm to room temperature and stirred overnight, then cooled to 0 ⁰ C and 25ml of IN HCl were added, then extracted with ethyl acetate. The organic layer was concentrated in vacuo. This residue was dissolved in 10ml of water, the pH was adjusted to 7 using saturated NaHCO ₃ solution, then extrated with ethylacetate (2x50 ml). The organic layer was separated, and the aqueous phase was treated with IN HCl to adjust the pH to 1. The aqueous phase was extracted with ethyl acetate twice (2x50 ml). The combined acidic organic extracts were dried over MgSO ₄ , filtered and concentrated in vacuo. ¹ H NMR (CD ₃ OD): δ 1.26 (m, 6H), 2.40 (m, 9H), 3.74 (s, 3H), 4.13 (m, 4H), 4.37 (m, IH), 5.12 (s, 2H), 7.37 (m, 5H). ³¹ P NMR (CD ₃ OD): δ 54.80. ¹³ C NMR (CD ₃ OD): δ 13.78, 23.89 (d, J=90.70 Hz), 24.11, 31.85 (d, J=93.75 Hz), 33.17, 52.13, 54.92, 60.62, 66.84, 128.00, 128.20, 128.66, 137.19, 157.43, 171.81, 172.18, 172.71.

(3S)-3-[(((3-amino-3-carboxy)propyl)(hydroxy)phosphinyl)-met hyI]pentane-l,5-dioic Acid (16). Compound 15 was dissolved in 3ml of 6N HCl. The mixture was heated for 15h at reflux temperature, the resulting solution was cooled to room temperature. Volatile organic byproducts and water were removed under vacuo and the residue was purified using a Dowex AG50x4 column as described earlier (63% yield over two steps). ¹ H NMR (D ₂ O): δ 1.63 (m, 2H); 2.00 (m, 2H); 2.33 (m, 3H); 2.58 (m, 2H); 3.91 (t, J=6.1 Hz, IH). ³¹ P NMR (D ₂ O): δ 57.10. ¹³ C NMR (D ₂ O) : δ 23.17, 23.42 (d, J=90.81 Hz), 31.84 (d, J=93.07 Hz), 33.62, 53.76 (d, J=14.6 Hz), 166.08, 172.16, 176.32 (d, J=12.26 Hz).

3-[((hydroxy)phosphinyl)-methyl]pentane-l,5-dioic Acid (17). The title compound was formed as a byproduct during the preparation of compound 15 and deprotected in the next step (procedure described above). During the deposition of 16, compound 17 was not bound to the cation exchange resin (Dowex AG50x4) and recovered. ¹ H NMR (D ₂ O): δ 2.44 (m, 5H), 6.85 (d, J=568 Hz, IH). ¹³ C NMR (D ₂ O): δ 31.93, 31.97 (d, J=125.7 Hz), 175.41 (d, J=I 1.13 Hz).

Scheme 2c, 2d

(3S)-2-[(((3-(N-Benzyloxycarbonyl)amino-3-methoxycarbonyl)pr opyl)(hydroxy)phosphinyl) -methyl]butane-l,4-dioic Acid Dimethyl Ester (18). The compound was prepared from 5 (0.8mmol) and diethylitaconate (474mg, 3mmol) by a procedure similar to that for the preparation of compound 15 (61% yield). ¹ H NMR (CD ₃ OD): δ 2.10 (m, 6H); 2.83 (m, 2H); 3.20 (m, IH); 3.75 (s, 3H); 3.72 (s, 3H); 3.71 (s, 3H); 4.30 (m, IH); 5.13 (s, 2H) 7.38 (m, 5H). ³¹ P NMR (CD ₃ OD): δ 52.21. ¹³ C NMR (CD ₃ OD): δ 24.26, 25.88 (d, J=93.39 Hz), 29.93 (d, J=93.39 Hz), 3S.85, 36.27, 51.53, 52.05, 54.13, 54.62, 66.82, 127.99, 128.20, 128.64, 137.20, 157.47, 172.42, 172.71, 174.56 (d, J=9.94 Hz).

(3S)-2-[(((3-amino-3-carboxy)propyl)(hydroxy)phosphinyl)-met hyl]butane-l,4-dioic Acid (19). The compound was prepared from 18 by the removal of protecting groups following the same procedure as that followed for compound 16 and purified by Dowex AG50x4 column to afford 19 (quantitative yield). ¹ H NMR (D ₂ O): δ 1.82 (m, 3H); 2.17 (m, 3H); 2.78 (m, 2H); 3.08 (m, IH); 4.04 (t, J=6.1 Hz, IH). ³¹ P NMR (D ₂ O): δ 56.35. ¹³ C NMR (D ₂ O): δ 23.27, 25.49 (d, J=91.38 Hz), 30.34 (d, J=91.25 Hz), 36.02, 36.95 (d, J=7.61 Hz), 53.71 (d, J=I 5.09 Hz), 172.12, 175.92, 178.28 (d, J=8.81 Hz).

(3S)-2-[(hydroxy)phosphinyl]-bismethylbutane-l,4-dioic Acid (20). The title compound was formed as a byproduct during the preparation of compound 18 and then deprotected in the next step (procedure described above). During the deposition of 19 on cation exchange resin, the compound 20 was not bound to the resin. ¹ H NMR (D ₂ O): δ 1.84 (m, 2H); 2.08 (m, 2H); 2.56 (d, J=6.69 Hz, 4H); 2.92 (m, 2H). ³¹ P NMR (D ₂ O): δ 62.83. ¹³ C NMR (D ₂ O): δ 30.26 (d, J=91.88 Hz), 35.49, 36.69, 175.46, 177.52 (d, J=8.74 Hz).

Scheme 3

Reagents and conditions: (a) 2-formylmethylbenzoate, CH ₂ Cl ₂ , BSA, 18h; (b) 6N HCl, reflux; (c) 3- formylmethyl benzoate, CH ₂ Cl ₂ , BSA, 15h; (d) 6N HCl, reflux

(35)-2-[(((3-(iV-BenzyIoxycarbonyI)amino-3-methoxycarboMyl)p ropyl)(hydroxy)phosphinyl) -hydroxymethyl]benzoic Acid Methyl Ester (21). The compound was prepared from 5 (0.8mmol) and ethyl 2-formylbenzoate (492mg, 3mmol) by using the procedure described for preparation of compound 15 (37% yield). ¹ H NMR (CD ₃ OD): δ 1.84 (m, 2H); 2.22 (m, 2H); 3.73 (s, 3H); 3.88 (s, 3H); 4.32 (m, IH); 5.10 (s, 2H); 5.84 (d, J=8.12 Hz, IH); 7.32 (m, 5H); 7.70 (m, 4H). ³¹ P NMR (CD ₃ OD): δ 41.22.

(3S)-2-[(((3-amino-3-carboxy)propyl)(hydroxy)phosphinyl)- hydroxymethyl]benzoic Acid

(22). The removal of the protecting groups in compound 21 was accomplished following the same procedure as that followed for compound 16 and purified by anion exchange AGl x4 column using the procedurce as described for compound 10. The compound 22 was eluted

with 0.4-0.5M HCOOH (quantitative yield). ¹ H NMR (D ₂ O): δ 1.67 (m _> 2H), 2.08 (m, 2H), 3.98 (m, IH), 5.74 (d, JN5.43 Hz, IH), 7.63 (t, J=7.65 Hz, IH), 7.69 (d, J=7.66 Hz, IH), 7.79 (t, J=7.17 Hz, IH), 7.91 (d, J=7.63 Hz, IH). ³¹ P NMR (D ₂ O): δ 43.20. ¹³ C NMR (D ₂ O): δ 22.53 (d, J=89.68 Hz), 23.55, 54.16, 72.92 (d, J=107.11 Hz), 128.22, 129.13, 129.38, 130.10, 132.43, 138.77, 170.82, 172.49.

(35)-3-[(((3-(iV-Benzyloxycarbonyl)amino-3-methoxycarbonyl)p ropyl)(hydroxy)phosphinyI) -hydroxy methyl] benzoic Acid Methyl Ester (23). The compound was prepared from 5 (O.δmmol) and methyl 3-formylbenzoate (492mg, 3mmol) by using the procedure described for preparation of compound 15 (55% yield). ¹ H NMR (CD ₃ OD): δ 1.79 (m, 4H), 3.60 (s, 3H), 3.76 (s, 3H), 4.26 (m, IH), 4.95 (m, IH), 5.02 (s, 2H), 7.30 (m, 5H), 7.83 (m, 4H). ³¹ P NMR (CD ₃ OD): δ 53.09, 53.53.

(3S)-3-[(((3-ammo-3-carboxy)propyl)(hydroxy)phosphinyl)-h ydroxymethyl]benzoic Acid

(24). The removal of the protecting groups in compound 21 was accomplished following the same procedure as that followed for compound 16 and purified by Dowex AG50x4 column to afford 24 (quantitative yield). ¹ H NMR (D ₂ O): δ 1.77 (m, 2H), 2.11 (m, 2H), 3.99 (m, IH), 4.93 (d, J=9.45 Hz, IH), 7.50 (t, J=7.73 Hz, IH), 7.66 (d, J=7.46 Hz, IH), 7.92 (d, J=7.57 Hz, IH), 8.00 (s, IH). ³¹ P NMR (D ₂ O): δ 50.53. ¹³ C NMR (D ₂ O): δ 22.53 (d, J=89.68 Hz), 23.55, 54.16, 72.92 (d, J=107.11 Hz), 128.22, 129.13, 129.38, 130.10, 132.43, 138.77, 170.82, 172.49.

Scheme 4

26 28

Reagents and conditions: (a) ethylbromoacetate, CH ₂ Cl ₂ , BSA, 15h; (b) 6N HCl, reflux; (c) ethyl 4,4,4-trifluoro crotonate, CH ₂ Cl ₂ , BSA, 15h; (d) 6N HCl, reflux

(3S)-2-[((3-(N-Benzyloxycarbonyl)amino-3- methoxycarbonyl)propyl)(hydroxy)phosphinyl] ethanoic Acid Ethyl Ester (25). The compound was prepared from 5 (O.Smmol) and ethylbromoacetate (501mg, 3mmol) by following the procedure described for preparation of compound 15 (60% yield). ¹ H NMR (CD ₃ OD): δ 1.28 (t, J= 7.1 Hz, 3H), 2.07 (m, 4H), 3.00 (d, J= 17.3 Hz, 2H), 3.76 (s, 3H), 4.19 (q, J= 7.1 Hz, 2H), 4.31 (m, IH), 5.13 (s, 2H), 7.34 (m, 5H). ¹³ C NMR (CD ₃ OD): δ 13.5, 24.2, 25.6 (d, J= 99 Hz), 37.2 (d, J= 82 Hz), 51.9, 54.8, 61.6, 66.8, 127.9, 128.1, 128.5, 137.1, 157.6, 167.1, 172.7. ³¹ P NMR (CD ₃ OD): δ 45.7. MS (ESI): m/z 400.1 (M-I).

(3S)-2-[((3-amino-3-carboxy)propyI)(hydroxy)phosphinyl]ethan oic Acid (26). The removal of the protecting groups in compound 25 was accomplished using the same procedure as that used for compound 16 and purified by Dowex AG50x4 column to afford 26 (quantitative yield). ¹ H NMR (D ₂ O): δ 1.86 (m, 2H), 2.22 (m, 2H), 2.82 (d, J=I 6.9 Hz, 2H), 4.08 (t, J=6.2 Hz, IH). ³¹ P NMR (D ₂ O): δ 46.61. ¹³ C NMR (D ₂ O): δ 21.85, 21.18 (d, J=96.0 Hz), 36.83 (d, J=76.7 Hz), 51.85, 170.33, 170.70. Mass (ESI): 226.1 (M-I). [α] _D +14.8° (c 0.1, H ₂ O).

(35)-3-[((3-(iV-Benzyloxycarboαyl)amino-3-methoxycarbonyI)p ropyI)(hydroxy)phosphinyl]-3- trifluoromethylpropanoic Acid Ethyl Ester (27). The compound was prepared from 5 (0.8mmol) and ethyl 4,4,4-trifluorocrotonate (504mg, 3mmol) by following the procedure described for preparation of compound 15 (64% yield). ¹ H NMR (CD ₃ OD): δ 1.24 (m, 3H), 2.02 (m, 4H), 2.87 (m, 3H), 3.74 (s, 3H), 4.17 (q, J=6.8 Hz, 2H), 4.24 (m, IH), 5.12 (s, 2H), 7.36 (m, 5H). ³¹ P NMR (CD ₃ OD): δ 43.24.

(35)-3-[((3-amino-3-carboxy)propyl)(hydroxy)phosphinyI]-3-tr ifluoroinethypropanoic Acid (28). The removal of the protecting groups in compound 27 was accomplished using the same procedure as that used for compound 16 to afford 28. Compound 27 was purified by Dowex AG50x4 column (quantitative yield). ¹ H NMR (D ₂ O): δ 1.81 (m, 2H), 2.17 (m, 2H), 2.79 (m, 2H), 3.15 (m, IH), 4.07 (m, IH). ³¹ P NMR (D ₂ O): δ 43.93, 46.21.

Scheme 5

Reagents and conditions: (a) CH ₂ Cl ₂ , BSA, 15h; (b) LiOH, EtOH, 12h; (c) 4N HCl, 75°C, 4h

(35)-4-[((3-(iV-Benzyloxycarbonyl)ainino-3-methoxycarbonyl)p ropyl)(hydroxy)phosphinyl]-4- hydroxy-3-methyI-2-butenoic Acid Ethyl Ester (29). The compound was prepared from 5 (0.8mmol) and ethyl-3-methyl-4oxocrotonate (426mg, 3mmol) by following the procedure described for preparation of compound 15. ¹ H NMR (CD ₃ OD): δ 1.26 (m, 3H), 2.16 (m, 7H), 3.74 (s, 3H), 4.19 (m, 3H), 4.48 (d, J= 13.69 Hz, IH), 5.12 (s, 2H), 5.86 (m, IH), 7.36 (m, 5H). ³¹ P NMR (CD ₃ OD): δ 49.0. ¹³ C NMR (CD ₃ OD): δ 13.96, 17.65, 22.63 (d, J= 89.68 Hz), 24.15, 52.17, 54.76, 60.73, 66.92, 74.05 (d, J= 101.52 Hz), 117.03, 127.98, 128.23, 128.68, 137.07, 155.87, 172.09, 172.81.

(3iS)-4-[((3-(iV-Benzyloxycarbonyl)amino-3-carboxy)propyI)(h ydroxy)phosphmyl]-4- hydroxy-3-methyl-2-butenoic Acid (30). Compound 29 (472mg) was dissolved in 10 ml of ethanol and 10 ml of water. Lithium hydroxide (144mg, 6mmol) in 5 ml water was added to the solution, which was stirred at room temperature for 12h. Following removal of ethanol under vacuo, the resulting solution pH was adjusted to 1. Then extracted with ethyl acetate twice. The organic layer was washed with brine and dried with anhydrous MgSO ₄ , and the solvent was evaporated in vacuo (66% yield over two steps). ¹ H NMR (CD ₃ OD): δ 1.88 (m, 7H), 4.21 (m, IH), 4.39 (d, J= 12.1 Hz, IH), 5.11 (s, 2H), 5.93 (m, IH), 7.39 (m, 5H). ³¹ P NMR (CD ₃ OD): δ 49.4.

(3S)-4-[((3-amino-3-carboxy)propyl)(hydroxy)phosphinyl]-4-hy droxy-3-methyI-2- butenoic Acid (31). The removal of the benzyloxy carbonyl group was accomplished by adding 4N HCl (5ml) to the compound 30 (140 mg). The resulting solution was stirred at 75 ⁰ C for 4h and cooled to room temperature. Volatile organic byproducts and water were removed under vacuo. The compound 31 was purified by anion exchange AGl χ4 column using the procedure described for compound 10. Compound 31 was eluted with 0.3M HCOOH (quantitative yield). ¹ H NMR (D ₂ O): δ 1.86 (m, 2H), 2.16 (m, 5H), 4.10 (m, IH), 4.43 (d, J= 13.34 Hz, IH), 5.99 (d, J= 3.85 Hz, IH). ¹³ C NMR (D ₂ O): δ 17.2, 22.40 (d, J= 100.23 Hz), 23.19, 53.5, 75.25 (d, J= 106.91 Hz), 116.35, 157.19, 170.54, 171.79. ³¹ P NMR (D ₂ O): δ 53.14.

Scheme 6

(3S)-2-[(((3-(λ ^r -Benzyloxycarbonyl)amino-3-methoxycarbonyI)propyl)(hydroxy)p hosphinyl) -hydroxymethyl]cydopropane-l-carboxylic Acid Ethyl Ester (32). The compound was prepared from 5 (0.8mmol) and trans ethyl 2-formyl-l-cyclopropanecarboxylate (426mg, 3mmol) by following the procedure described for preparation of compound 15 (55% yield). ¹ H NMR (CD ₃ OD) : δ 1.19 (m, 5H), 1.96 (m, 6H), 3.40 (m, 0.5H), 3.67 (m, 0.5H), 3.73 (s, 3H), 4.12 (m, 2H), 4.29 (m, IH), 5.11 (s, 2H), 7.37 (m, 5H). ³¹ P NMR (CD ₃ OD) : δ 50.53.

(3iS)-2-[(((3-amino-3-carboxy)propyl)(hydroxy)phosphinyl)-hy droxyinethyl]cyclopropane-l- carboxylic Acid (33). The removal of the protecting groups in compound 27 was accomplished using the same procedure as that used for compound 16 to afford 33 and 34 (1:1, quantitative yield). The mixture (26mg) of the isomers 33 and 34 was separated by Dowex 50x4 (H ⁺ , 200- 400 mesh, 44x2.2cm, water elution) chromatography. Diastereoisomers 33 and 34 were separated in fractions 9-14 (4.4mg) and 33-37 (3.1mg) respectively. 33: ¹ H NMR (D ₂ O): δ 1.12 (m, IH), 1.25 (m, IH), 1.80 (m, 4H), 2.13 (m, 2H), 3.40 (m, IH), 3.96 (m, IH). ³¹ P NMR (D ₂ O): δ 51.50. 34: ¹ H NMR (D ₂ O): δ 1.14 (m, IH); 1.34 (m, IH); 1.82 (m, 4H); 2.15 (m, 2H); 3.15 (m, IH); 4.00 (m, IH). ³¹ P NMR (D ₂ O): δ 51.50. ¹³ C NMR (D ₂ O): δ 13.32 (d, J=78.49 Hz), 18.37 (d, J=42.77 Hz), 22.63 (d, J=79.30 Hz), 23.23 (d, J=78.93 Hz), 23.26, 53.94, 70.56 (d, J=109.05 Hz), 72.31 (d, J=I 12.07 Hz), 172.47, 178.52.

Scheme 7

Reagents and conditions: (a) CH ₂ Cl ₂ , BSA, 15h; (b) 6N HCl, reflux

(3S)-3-[(((3-(N-Benzyloxycarbonyl)amino-3- methoxycarbonyl)propyl)(hydroxy)phosphinyl] furanone (3S). The compound was prepared from 5 (O.Smmol) and 2-(5H)-furanone (252mg, 3mmol) by following the procedure described for preparation of compound 15 (75% yield). ¹ H NMR (CD ₃ OD): δ 1.88 (m, 2H), 2.15 (m, 2H), 2.73 (m, 2H), 3.01 (m, IH), 3.76 (s, 3H), 4.36 (m, IH), 4.51 (m, 2H), 5.13 (s, 2H), 7.36 (m, 5H). ³¹ P NMR (CD ₃ OD): δ 49.2. ¹³ C NMR (CD ₃ OD): δ 24.05, 24.69 (d, J= 80.81), 28.63, 34.5 l(d, J= 96.66), 51.93, 54.90, 66.82, 67.71, 127.91, 128.13, 128.55, 137.12, 157.64, 172.76, 177.27 (d, J= 9.94).

(3S)-4-[((3-amino-3-carboxy)propyl)(hydroxy)phosphmyl]furano ne (36). The removal of the protecting groups in compound 3S was accomplished using the same procedure as that used for compound 16 and purified by Dowex AG50χ4 column to afford 36 (quantitative yield). ¹ H NMR (D ₂ O): δ 1.72 Qn, 2H), 2.15 Qn, 2H), 2.80 Qn, 3H), 4.10 (d, J= 6.4 Hz, IH), 4.42 Qn, IH), 4.61 Qn, IH). ³¹ P NMR (D ₂ O): δ 51.21. ¹³ C NMR (D ₂ O): δ 23.19, 24.45 (d, J=93.71 Hz), 29.47, 34.86 (d, J=96.14 Hz), 54.2, 69.44, 172.03, 180.73 (d, J= 10.2).

Scheme 8

Reagents and conditions: (a) 3-nitro-4-(trifluoromethyl)benzaldehyde, CH ₂ Cl ₂ , BSA, 15h; (b) 6N HCl, reflux; (c) 4-formylmethyl benzoate, CH ₂ Cl ₂ , BSA, 15h; (d) 6N HCl, reflux

(3S)-3-[(((3-(N-Benzyloxycarbonyl)amino-3-methoxycarbonyl)pr opyl)(hydroxy)phosphinyl) -hydroxymethyl]-6-trifluoromethyI-l-nitrobenzene (37). 37 was prepared from 5 (0.8mmol) and 3-nitro-4-(trifluoromethyl)benzaldehyde (657mg, 3mmol) by following the procedure described for preparation of compound 15. ¹ H NMR (CD ₃ OD): δ 2.04 (m, 4H), 3.75 (s, 3H), 4.33 (m, IH), 5.15 (s, 2H), 6.21 (m, IH), 7.36 (m, 5H), 8.15 (m, 3H). ³¹ P NMR (CD ₃ OD): δ 48.14.

(3S)-3-[(((3-amino-3-carboxy)propyl)(hydroxy)phosphmyI)-6 -trifluoromethyI-l- nitrobenzene (38). The removal of the protecting groups in compound 37 was accomplished using the same procedure as that used compound 16 and purified by Dowex AG50x4 column

to afford 38. ¹ H NMR (D ₂ O) : δ 1.75 (m, 2H), 2.10 (m, 2H), 4.01 (m, IH), 5.97 (d, J= 10.95 Hz, IH), 8.02 (m, 2H); 8.35 (s, IH). ³¹ P NMR (D ₂ O) : δ 48.25.

(3>S)-4[(((3-(iV-Benzyloxycarbonyl)amino-3-methoxycarbony l)propyl)(hydroxy)phosphinyl) -hydroxymethyljbenzoic Acid Methyl Ester (39). 39 was prepared from 5 (0.8mmol) and methyl 4- formylbenzoate (492mg, 3mmol) by using the procedure described for preparation of compound 15. ¹ H NMR (CD ₃ OD): δ 2.03 (m, 4H), 3.73 (s, 3H), 3.92 (s, 3H), 4.29 (m, IH), 5.21 (s, 2H), 5.47 (m, IH), 7.37 (m, 5H), 7.65 (m, 2H), 8.03 (m, 2H). ³¹ P NMR (D ₂ O): δ 48.81. ¹³ C NMR (CD ₃ OD): δ 23.39 (d, J= 91.57 Hz), 24.12, 51.82, 66.88, 72.16 (d, J= 108.61 Hz), 127.41, 127.86, 128.13, 128.60, 129.34, 129.66, 137.06, 143.48, 157.65, 167.53, 172.78.

(3S)-4-[(((3-amino-3-carboxy)propyl)(hydroxy)phosphinyl)-hyd roxymethyl]benzoic Acid (40). The removal of the protecting groups in compound 39 was accomplished following the same procedure as that followed for compound 16 and purified by Dowex AG50x4 column to afford 40. ¹ H NMR (D ₂ O): δ 1.65 (m, 2H), 1.94 (m, 2H), 3.94 (m, IH), 4.90 (d, J=10.4 Hz, IH), 7.48 (d, J=7.19 Hz, 2H), 7.93 (d, J=8.22 Hz, 2H). ³¹ P NMR (D ₂ O): δ 49.89. ¹³ C NMR (D ₂ O): δ 22.71 (d, J=90.3 Hz), 23.70, 54.52, 73.44 (d, J=104.96 Hz), 127.34, 129.21, 130.00, 144.38, 170.89, 172.73.

Scheme 9

(25)-2-(iV-Beiizyloxycarbony l)amino-4- [(hy droxy)phosphinyl] butanoic Acid Methyl Ester (5). A mixture of hypophosphorous acid (660mg, 5mmol, 50% aqueous), Z-Z- vinyl glycine methyl ester (250mg, Immol) and α,α'-azoisobutyronitrile (AIBN, 8.1mg, 0.05mmol) in methanol (ImI) was refluxed at 8O ⁰ C for 5 h. Then the methanol was evaporated under vacuum and the residue was extracted with ethyl acetate, dried over MgSO ₄ . The organic layer was evaporated under vacuum and purified by Silica gel chromatography (CH ₂ Cl ₂ :Me0H, 1:0 to 9:1) to afford 5 (90% yield); ¹ H NMR (CD ₃ OD): δ 1.98 (m, 4H), 3.72

(S ₅ 3H), 4.11 (m, IH), 5.12 (s, 2H) ₅ 7.34 (m ₅ 5H). ¹³ C NMR (CD ₃ OD): δ 13.8, 23.4, 26.1 (d, J= 92 Hz), 52.2, 54.7, 66.9, 128.0, 128.3, 128.7, 137.2, 157.5, 172.7. ³¹ P NMR (CD ₃ OD): δ

35.3.

Scheme 10

42 44

Reagents and conditions: (a) diethylvinylphosphonate, CH ₂ Cl ₂ , BSA, 15h; (b) 8N HCl, reflux; (c) triethyl-4- phosphonocrotonate, CH ₂ Cl ₂ , BSA, 15h; (d) 8N HCl, reflux

(3 _* S)-2-[((3-(N-Benzyloxycarbonyl)amino-3- methoxycarbonyl)propyl)(hydroxy)phosphinyl] ethylphosphonate Diethyl Ester (41).

The compound was prepared from 5 (0.8mmol) and diethylvinylphosphonate (492mg, 3mmol) by using the procedure described for preparation of compound 15 (87.8% yield). ¹ H NMR (CD ₃ OD): δ 1.29 (m, 6H), 1.99 (m, 8H), 3.73 (s, 3H), 4.14 (m, 4H), 4.31 (m, IH), 5.12 (s, 2H), 7.37 (m, 5H). ³¹ P NMR (CD ₃ OD): δ 32.57 (d, J=65.87 Hz), 52.31 (d, J=65.59 Hz). MS (ESI): m/z 480.1 (M+l).

(3S)-3-[((3-Amino-3-carboxy)propyl)(hydroxy)phosphinyl]ethyl phosphonate (42). The removal of the protecting groups in compound 21 was accomplished following the same procedure as that followed for compound 16 and purified by anion exchange AGl x4 column using the procedurce as described for compound 10. The compound 42 was eluted with 0.8- l.OM HCOOH (quantitative yield). ¹ H NMR (D ₂ O) : δ 1.75 (m, 6H), 2.00 (m, 2H), 3.97 (t, J=5.79 Hz, IH). ³¹ P NMR (D ₂ O) : δ 38.21 (d, J=65.00 Hz), 61.99 (d, J=65.13 Hz). MS (ESI): m/z 276.1 (M+l).

(3S)-2-[(((3-(N-Benzyloxycarbonyl)amino-3-methoxycarbonyl)pr opyl)(hydroxy)phosphinyl) -methyl]-2-(diethylphosphonomethy)-propanoic Acid Ethyl Ester (43). The compound was prepared from 5 (0.8mmol) and triethyl-4-phosphonocrotonate (750mg, 3mmol) by a procedure similar to that for the preparation of compound 15 (83.8% yield). ¹ H NMR (CD ₃ OD): δ 1.28 (m, 9H), 2.19 (m, 6H), 2.81 (m, 3H), 3.73 (s, 3H), 4.12 (m, 6H), 4.32 (m, IH), 5.12 (s, 2H), 7.37 (m, 5H). ³¹ P NMR (CD ₃ OD): δ 31.29 (d, J=57.26 Hz), 53.97 (d, J=57.27 Hz). MS (ESI): m/z 566.1 (M+l).

(3S)-2-[(((3-(N-BenzyloxycarbonyI)amino-3-methoxycarbonyI)pr opyI)(hydroxy)phosphinyl) -methyl] -2-(phosphonomethy)-propanoic Acid (44). The removal of the protecting groups in compound 43 was accomplished using the same procedure as that used compound 16 and purified by anion exchange AGl χ4 column using the procedurce as described for compound 10. The compound 44 was eluted with 1.0-1.3M HCOOH (quantitative yield). ¹ H NMR (D ₂ O): δ 1.62 (m, 3H), 1.86 (m, 3H), 2.26 (m, IH), 2.41 (m, IH), 2.47 (m, IH), 3.85 (m, IH). ³¹ P NMR (D ₂ O): δ 37.51 (d, J=50.72 Hz), 63.67 (d, J=50.67 Hz). ¹³ C NMR (CD ₃ OD): δ 22.20 (d, J=91.35 Hz), 22.47, 25.11 (d, J=136.71 Hz), 29.72 (d, J=92.69 Hz), 33.38, 52.98, 171.12, 175.30 (d, J=8.05 Hz).

Scheme 11

Reagents and conditions: (a) methyl-3-(bromomethyl)benzoate, CH ₂ Cl ₂ , BSA, 15h; (b) 6N HCl, reflux; (c) methyl-4-iodobutyrate, CH ₂ Cl ₂ , BSA, 15h; (d) 6N HCl, reflux

(3iS)-3-[(((3-(iV-Benzyloxycarbonyl)ainino-3-methoxycarbonyl )propyl)(hydroxy)phosphinyl) -methyl] benzoic Acid Methyl Ester (45). The compound was prepared from 5 (0.8mmol) and methyl-3-(bromomethyl)-benzoate (687mg, 3mmol) by using the procedure described for preparation of compound 15 (72.2% yield). ¹ H NMR (CD ₃ OD): δ 1.98 (m, 4H), 3.23 (d, J=15.04 Hz, 2H), 3.69 (s, 3H), 3.86 (s, 3H), 4.31 (m, IH), 5.09 (s, 2H), 7.33 (m, 5H), 7.43 (m, 2H), 7.94 (m, 2H). ³¹ P NMR (CD ₃ OD): δ 50.20. ¹³ C NMR (D ₂ O): δ 24.35, 24.62 (d, J=93.22 Hz), 36.18, (d, J=88.71 Hz), 52.00, 54.93, 66.91, 128.02, 128.24, 128.68, 128.95, 130.63, 131.21, 133.19 (d, J=7.48 Hz), 134.93, 137.11, 157.50, 172.75, 174.39. MS (ESI): m/z 464.1 (M+l).

(3S)-3-[(((3-amino-3-carboxy)propyl)(hydroxy)phosphinyl)- methyI]benzoic Acid (46).

The removal of the protecting groups in compound 45 was accomplished following the same procedure as that followed for compound 16 and purified by Dowex AG50x4 column to afford 46 (quantitative yield). ¹ H NMR (D ₂ O): δ 1.60 (m, 2H), 2.00 (m, 2H), 3.08 (d, JH6.78 Hz, 2H), 3.93 (t, J=6.02 Hz, IH), 7.39 (m, 2H), 7.76 (m, 2H). ³¹ P NMR (D ₂ O): δ 54.66. ¹³ C NMR (D ₂ O): δ 23.42, 24.38 (d, J=91.69 Hz), 37.21 (d, J=85.97 Hz), 53.80 (d, J=14.83 Hz), 128.24, 129.34, 130,24, 130.86, 133.98 (d, J=7.67 Hz), 135.11, 170.68, 172.20. MS (ESI): m/z 302.1 (M+l).

(35)-4-[((3-(iV-Benzyloxycarbonyl)amino-3-methoxycarbonyl)pr opyl)(hydroxy)phosphmyl] butanoic Acid Methyl Ester (47). The compound was prepared from 5 (0.8mmol) and methyl- 4-iodobutyrate (684mg, 3mmol) by using the procedure described for preparation of compound 15 (64.6% yield). ¹ H NMR (CD ₃ OD): δ 2.14 (m, 10H), 3.68 (s, 3H), 3.74 (s, 3H), 4.34 (m, IH), 5.12 (s, 2H), 7.36 (m, 5H). ³¹ P NMR (CD ₃ OD): δ 55.43. MS (ESI): m/z 416.1 (M+l).

(3S)-4-[((3-Amino-3-carboxy)propyl)(hydroxy)phosphinyl]butan oic Acid (48). The removal of the protecting groups in compound 47 was accomplished following the same procedure as that followed for compound 16 and purified by Dowex AG50x4 column to afford 48 (quantitative yield). ¹ H NMR (D ₂ O): δ 1.71 (m, 6H), 2.08 (m, 2H), 2.44 (m, 2H), 3.93 (t, J=5.98 Hz, IH). ³¹ P NMR (D ₂ O): δ 58.80. MS (ESI): m/z 254.1 (M+l).

Scheme 12

^a Reagents and conditions : (a) 4-hydroxy-3-nitrobenzaldehyde, CH ₂ Cl ₂ , BSA, 15h; (b) 6N HCl, 100°C , 5h; (c) 5-nitrovanillin, CH ₂ Cl ₂ , BSA, 15h; (d) 6N HCl, 100°C , 5h.

(3S)-3-[(((3-(N-Benzyloxycarbonyl)amino-3-methoxycarbonyl)pr opyl)(hydroxy) phosphinyl)-hydroxymethyl]-6-hydroxy-l-nitrobenzene (61). 61 was prepared from 5 (0.8mmol) and 4-hydroxy-3-nitrobenzaldehyde (401mg, 2.4mmol) by following the procedure described for preparation of compound 15. ¹ H NMR (CD ₃ OD): δ 2.02 (m, 4H), 3.74 (s, 3H), 4.33 (m, IH), 5.02(d, J= 8.60 Hz, IH), 5.09 (s, 2H), 7.13 (d, J= 8.54 Hz, IH), 7.31 (m, 5H), 7.61 (d, J= 8.76 Hz, IH), 8.08 (s, IH). ³¹ P NMR (CD ₃ OD): δ 48.76.

(3S)-3-[(((3-amino-3-carboxy)propyl)(hydroxy)phosphinyI)- hydroxymethy]-6-hydroxy- 1 -nitrobenzene (62). The removal of the protecting groups in compound 61 was accomplished using the same procedure as that used compound 16 and purified by Dowex

AG50x4 column to afford 62. ¹ H NMR (D ₂ O) : δ 1.78 (m, 2H), 2.05 (m, 2H), 3.98 (m, IH) ₉ 4.80 (d, J= 8.56 Hz, IH), 7.06 (d, J= 8.66 Hz, IH); 7.57 (d,J= 8.63 Hz, IH), 8.02 (s, IH). ¹³ C NMR (D ₂ O): δ 22.59 (d, J= 88.4 Hz), 23.61, 53.98 (d, J= 14.72 Hz), 71.75 (d, J= 107.37 Hz), 119.99, 123.70, 130.83, 134.31, 136.83, 153.28, 172.36.

(3S)-3-[(((3-(N-Benzyloxycarbonyl)amino-3-methoxycarbonyl)pr opyl)(hydroxy) phosphinyl)-hydroxymethyI]-5-methoxy-6-hydroxy-l-nitrobenzen e (63). 63 was prepared from 5 (0.8mmol) and 5 -nitro vanillin (473mg, 2.4mmol) by using the procedure described for preparation of compound 15. ¹ H NMR (CD ₃ OD): δ 2.12 (m, 4H), 3.73 (s, 3H), 3.92 (s, 3H), 4.32 (m, IH), 5.08 (s, 2H), 5.33 (m, IH), 7.53 (m, 7H). ³¹ P NMR (CD ₃ OD): δ 49.29.

(3S)-3-[(((3-amino-3-carboxy)propyl)(hydroxy)phosphinyl)-hyd roxymethyI]-5-methoxy- 6-hydroxy-l-nitrobenzene (64). The removal of the protecting groups in compound 63 was accomplished following the same procedure as that followed for compound 16 and purified by Dowex AG50x4 column to afford 64. ¹ H NMR (D ₂ O) : δ 1.74 (m, 2H), 2.03 (rø, 2H), 3.83 (s, 3H), 4.02 (m, IH), 7.23 (s, IH), 7.59 (s, IH). ³¹ P NMR (D ₂ O): δ 50.03. ¹³ C NMR (D ₂ O): δ 22.63 (d, J= 90.45 Hz), 23.68, 54.16 (d, J= 12.65 Hz), 56.91, 72.10 (d, J= 109.9 Hz), 114.43, 116.81, 129.99, 134.24, 143.91, 149.30, 172.56. MS (ESI) m/z: 365.1 (M+l).

Scheme 13

^a Reagents and conditions : (a) 4-chloro-3-nitrobenzaldehyde, CH ₂ Cl ₂ , BSA, 15h; (b) 6N HCl, 100°C , 5h; (c) 4- morpholino-3-nitrobenzaldehyde, CH ₂ Cl ₂ , BSA, 15h; (d) 6N HCl, reflux, 5h.

(3S)-3-[(((3-(N-Benzyloxycarbonyl)amino-3-methoxycarbonyl)pr opyl)(hydroxy) phosphinyl)-hydroxymethyI]-6-chloro-l-nitrobenzene (65). 65 was prepared from 5 (0.8mmol) and 4-chloro-3-nitrobenzaldehyde (445mg, 2.4mmol) by following the procedure described for preparation of compound 15. ¹ H NMR (CD ₃ OD): δ 2.03 (m, 4H), 3.73 (s, 3H), 4.31 (m, IH), 5.11 (s, 2H), 5.25 (d, J= 7.0 Hz, IH), 7.34 (m, 5H), 7.65 (m, 2H), 8.07 (s, IH). ³¹ P NMR (CD ₃ OD): δ 46.26.

(3S)-3-[(((3-amino-3-carboxy)propyl)(hydroxy)phosphinyl)-hyd roxymethyl]-6-chloro-l- nitrobenzene (66). The removal of the protecting groups in compound 65 was accomplished using the same procedure as that used compound 16 and purified by Dowex AG50χ4 column to afford 66. ¹ H NMR (D ₂ O): δ 1.73 (m, 2H), 2.12 (m, 2H), 4.02 (m, IH), 4.91 (d, J= 9.91 Hz, IH), 7.60 (m, 2H); 7.98 (s, IH). ³¹ P NMR (D ₂ O): δ 49.02. ¹³ C NMR (D ₂ O): δ 22.66 (d, J=

87.3 Hz), 23.55, 53.92 (d, J= 14.03 Hz), 72.00 (d, J= 106.4 Hz), 124.30, 125.79, 132.12, 132.56, 139.37, 147.39, 172.27. MS (ESI) m/∑: 353.1 (M+l).

(3S)-3-[(((3-(N-Benzyloxycarbonyl)amino-3-methoxycarbonyl)pr opyl)(hydroxy) phosphinyl)-hydroxymethyI]-6-morpholino-l-nitrobenzene (67). 67 was prepared from 5 (0.8mmol) and 4-morpholiuo-3-nitrobenzaldehyde (566mg, 2.4mmol) by using the procedure described for preparation of compound 15. ¹ H NMR (CD ₃ OD): δ 2.05 (m, 4H), 3.07 (m, 4H), 3.74 (s, 3H), 3.80 (m, 4H), 4.27 (m, IH), 4.96 (d, J= 9.18 Hz, IH), 5.12 (s, 2H), 7.30 (m, 6H), 7.67 (d, J= 8.49 Hz, IH), 7.91 (s, IH). ³¹ P NMR (CD ₃ OD): δ 45.98.

(3S)-3-[(((3-amino-3-carboxy)propyl)(hydroxy)phosphinyl)-hyd roxymethyI]-6- morpholino-1-nitro benzene (68). The removal of the protecting groups in compound 67 was accomplished following the same procedure as that followed for compound 16 and purified by Dowex AG50x4 column to afford 68. ¹ H NMR (D ₂ O): δ 1.64 (m, 2H), 2.05 (m, 2H), 3.03 (m, 4H), 3.73 (m, IH), 3.81 (m, 4H), 4.79(d, J= 8.81 Hz, IH), 7.27 (d, J= 8.54 Hz, IH), 7.61 (d, J= 8.36 Hz, IH), 7.91 (s, IH). ³¹ P NMR (D ₂ O): δ 48.06. ¹³ C NMR (D ₂ O): δ 23.13 (d, J= 90.9 Hz), 24.04, 52.06, 55.72, 66.88, 72.20 (d, J= 106.9 Hz), 121.29, 125.03, 133.60, 133.71, 142.22, 145.25, 174.46.

Scheme 14

"Reagents and conditions : (a) 2,4-dinitrobenzaldehyde, CH ₂ Cl ₂ , BSA, 15h; (b) 6N HCl, 100°C , 5h

(3S)-4-[(((3-(N-BenzyloxycarbonyI)amino-3-methoxycarbonyl)pr opyl)(hydroxy) phosphiπyl)-hydroxymethyl]-l,3-dinitrobenzene (69). The compound (69) was prepared from 5 (0.8mmol) and 4-methoxy-3-nitrobenzaldehyde (470 mg, 2.4mmol) by following the procedure described for preparation of compound 15. ¹ H NMR (CD ₃ OD): δ 2.02 (m, 4H), 3.74 (s, 3H), 4.32 (m, IH), 5.10 (s, 2H), 6.18 (m, IH), 7.33 (m, 5H), 8.41 (m, 2H), 8.76 (d, J=8.39 Hz, IH). ³¹ P NMR (CD ₃ OD): δ 47.96.

(3S)-4-[(((3-amino-3-carboxy)propyl)(hydroxy)phosphinyl)-hyd roxymethyl]-l,3- dinitrobenzene (70). The removal of the protecting groups in compound 69 was accomplished following the same procedure as that followed for compound 16 and purified by Dowex AG50x4 column to afford 70. ¹ H NMR (D ₂ O): δ 1.80 (m, 2H), 2.04 (m, 2H), 4.02 (m, IH), 6.02 (d, J=I 1.15 Hz, IH), 7.93 (d, J=8.70 Hz, IH), 8.32 (s, IH), 8.65 (d, J=7.33 Hz, IH). ³¹ P NMR (D ₂ O): δ 54.37.

Scheme 15

^a Reagents and conditions : (a) 3-nitro-4-(fluoro)benzaldehyde, CH ₂ Cl ₂ , BSA, 15h; (b) 6N HCl, reflux; (c) 3- nitro-4-(methyl)benzaldehyde, CH ₂ Cl ₂ , BSA, 15h; (d) 6N HCl, reflux

(3S)-3-[(((3-(N-BenzyloxycarbonyI)amino-3- methoxycarbonyl)propyl)(hydroxy)phosphinyl)-hydroxymethyl]-6 -fluoro-l- nitrobenzene (49).

49 was prepared from 5 (O.Smmol) and 3-nitro-4-(fluoro)benzaldehyde (507.3mg, 3mmol) by following the procedure described for preparation of compound 15. ¹ H NMR (CD ₃ OD): δ 2.16 (m, 4H), 3.75 (s, 3H), 4.34 (m, IH), 5.12 (s, 2H), 5.49 (d, J= 7.11 Hz, IH), 7.39 (m, 6H), 7.86 (m, IH), 8.26 (m, IH). ³¹ P NMR (CD ₃ OD): δ 47.99.

(3S)-3-[(((3-amino-3-carboxy)propyl)(hydroxy)phosphmyl)-6 -fluoro-l-nitrobenzene (50).

The removal of the protecting groups in compound 49 was accomplished using the same

procedure as that used compound 16 and purified by Dowex AG50x4 column to afford 50. ¹ H NMR (D ₂ O): δ 1.75 (m, 2H), 2.11 (m, 2H), 4.00 (m, IH), 4.89 (d, J= 9.02 Hz, IH), 7.35 (m, IH), 7.70 (m, IH), 8.09 (d, J= 6.84 Hz, IH). ³¹ P NMR (D ₂ O): δ 49.37.

(3S)-3-[(((3-(N-Benzyloxycarbonyl)amino-3- methoxycarbonyl)propyl)(hydroxy)phosphinyl)

-hydroxymethyl]-6-methyl-l-nitrobenzene (51). The compound was prepared from 5 (O.δmmol) and 3-nitro-4-(methyl)benzaldehyde (495.5mg, 3mmol) by using the procedure described for preparation of compound 15. ¹ H NMR (CD ₃ OD): δ 2.14 (m, 4H), 2.55 (s, 3H),

3.74 (s, 3H), 4.32 (m, IH), 5.12 (s, 2H), 5.46 (d, J= 7.54 Hz, IH), 7.37 (m, 6H), 7.70 (d, J=

7.75 Hz, IH), 8.13 (s, IH). ³¹ P NMR (CD ₃ OD): δ 48.69.

(3S)-3-[(((3-amino-3-carboxy)propyl)(hydroxy)phosphinyI)- 6-methyl-l-nitrobenzene

(52). The removal of the protecting groups in compound 51 was accomplished using the same procedure as that used compound 16 and purified by Dowex AG50x4 column to afford 52. ¹ H NMR (D ₂ O): δ 1.61 (m, 2H), 2.03 (m, 2H), 2.47 (s, 3H), 3.68 (m, IH), 4.81 (d, J= 8.89 Hz, IH), 7.36 (d, J= 7.92 Hz, IH), 7.54 (d, J= 7.78 Hz, IH), 7.96 (s, IH). ³¹ P NMR (D ₂ O): δ 47.99.

40

46

Scheme 16

^a Reagents and conditions : (a) CH ₂ Cl ₂ , BSA, 15h; (b) 6N HCl, reflux

( 3S)-4-[(((3-(N-Benzyloxycarbonyl)amino-3- methoxycarbonyl)propyl)(hydroxy)phosphinyl)

-hydroxymethyl]-l-trifluoromethylbenzene (53). The compound was prepared from 5 (0.8mmol) and 4-(trifluoromethyl)benzaldehyde (522.4mg, 3mmol) by a procedure similar to that for the preparation of compound 15. ¹ H NMR (CD ₃ OD): δ 2.13 (m, 4H), 3.72 (s, 3H), 4.32 (m, IH), 5.11 (m, 3H), 7.35 (m, 5H), 7.72 (m, 4H). ³¹ P NMR (CD ₃ OD): δ 48.75.

(3S)-4-[(((3-amino-3-carboxy)propyl)(hydroxy)phosphinyl)- l-trifluoromethylbenzene

(54). The removal of the protecting groups in compound 53 was accomplished using the same procedure as that used compound 16 and purified by Dowex AG50x4 column to afford 54. ¹ H NMR (D ₂ O): δ 1.65 (m, 2H), 1.94 (m, 2H), 3.94 (m, IH), 4.89 (d, J= 9.99 Hz, IH), 7.50 (d, J= 7.94 Hz, 2H), 7.64 (d, J= 7.93 Hz, 2H). ³¹ P NMR (D ₂ O): δ 50.59.

Scheme 17

"Reagents and conditions : (a) CH ₂ Cl ₂ , BSA, 15h; (b) 6N HCl, reflux

(3S)-3-[(((3-(N-Benzyloxycarboayl)amino-3-methoxycarbonyl)pr opyl) (hydroxy) phos- pbinyl)-hydroxymethyl] 3-nitrobenzene (55). The compound was prepared from 5 (0.8mmol) and 3-nitrobenzaldehyde (453mg, 3mmol) by using the procedure described for preparation of compound IS. ¹ H NMR (CD ₃ OD): 5 2.15 (m, 4H), 3.73 (s, 3H), 4.31 (m, IH), 5.12 (s, 2H), 5.16 (m, IH), 7.34 (m, 5H), 7.61 (m, IH), 7.91 (m, IH), 8.16 (m, IH), 8.42 (s, IH). ³¹ P NMR (CD ₃ OD): δ 48.40.

(3S)-3-[(((3-amino-3-carboxy)propyl)(hydroxy)phosphinyl)-hyd roxymethyl] 3-nitrobenzene (56). The removal of the protecting groups in compound 55 was accomplished following the same procedure as that followed for compound 16 and purified by Dowex AG50x4 column to afford 56 (quantitative yield). ¹ H NMR (D ₂ O): δ 1.72 (m, 2H), 2.09 (m, 2H), 4.01 (m, IH), 4.94 (d, J=9.57 Hz, IH), 7.53 (t, J=7.99 Hz, IH), 7.74 (d, J=7.53 Hz, IH), 8.09 (d, J=8.17 Hz, IH), 8.20 (s, IH). ³¹ P NMR (D ₂ O): δ 49.69.

Scheme 18

"Reagents and conditions : (a) CH ₂ Cl ₂ , BSA, 15h; (b) 6N HCl, 100°C, 5h

(3S)-3- [(((3-(N-Benzy Ioxycarbonyl)amino-3-methoxy carbonyl)propyl) (hydroxy) phos- phinyl)-hydroxymethyl] 3-nitro-4-methoxybenzene (57). The compound was prepared from 5 (0.8mmol) and 4-methoxy-3-nitrobenzaldehyde (543 mg, 3mmol) by following the procedure described for preparation of compound 15. ¹ H NMR (CD ₃ OD): δ 2.10 (m, 4H), 3.73 (s, 3H), 3.92 (s, 3H), 4.31 (m, IH), 5.02 (d, J=8.49 Hz, IH), 5.12 (s, 2H), 7.22 (d, J=8.63 Hz, IH), 7.35 (m, 5H), 7.72 (d, J=8.3 Hz, IH), 8.01 (s, IH). ³¹ P NMR (CD ₃ OD): δ 48.73.

(35)-3-[(((3-amino-3-carboxy)propyl)(hydroxy)phosphinyl)-hyd roxymethyl] 3-nitro-4- methoxybenzene (58). The removal of the protecting groups in compound 57 was accomplished following the same procedure as that followed for compound 16 and purified by Dowex AG50x4 column to afford 58. ¹ H NMR (D ₂ O): δ 1.73 (m, 2H), 2.09 (m, 2H), 3.91 (s, 3H), 4.00 (m, IH), 4.83 (d, J=8.67 Hz, IH), 7.24 (d, J=8.8 Hz, IH), 7.64 (d, J=8.78 Hz, IH), 7.93 (s, IH). ³¹ P NMR (D ₂ O): δ 50.13.

Scheme 19

59 60 ^a Reagents and conditions : (a) AIBN, CH ₃ OH , reflux at 80°C, 5h; (b) dibromoethane, reflux at 12O°C, 5h; (c) CH(OEt) ₃ , reflux at 140°C; (d) diethylacetamidorαalonate, K ₂ CO ₃ , tetrabutylammonium bromide in THF, reflux ; (e) 8N HCl, reflux, 15h

5-[((3-(iV-Acetyl)ainino)-3-(bisethoxycarbonyl)propyl)(ethox y)phosphinyl]pentanoic Acid Ethyl Ester (59). A mixture of hypophosphorous acid (3.3g, 25mmol, 50% aqueous), diethylallylmalonate (lmg, 5mmol) and α,α'-azoisobutyronitrile (AIBN, 41mg, 0.25mmol) in methanol (2ml) was refluxed at 8O ⁰ C for 5 h. Then the methanol was evaporated under vacuum and the residue was extracted with ethyl acetate, dried over MgSO ₄ . The organic layer was evaporated under vacuum. Then the crude product (1.338g) was mixed with dibromoethane (2.4ml, 28mmol) and hexamethydisilazane (2.96ml, 14mmol) was heated at 120°C for 9h. The formed trimethylbromosilane and excess dibromoethane were removed under vacuum. Then 50 ml of aqueous ethanol (1:1) were added dropwise to the residue and refluxed for 0.5 h. Then the solvent was removed under vacuum and extracted with ethyl acetate. The organic layer was dried over MgSO ₄ and the solvent was removed under vacuum.

The crude product (270mg) was treated with 40ml of triethyl orthoformate, and the mixture was refluxed with a Dean-Stark trap to remove ethanol and ethyl formate. Excess of triethylorthoformate was removed under vacuum. The crude product (200mg) was mixed with diethylacetamidomalonate (174mg, O.Smmol), potassium carbonate (221mg, l.βmmol) and tetrabutylammonium bromide (13mg, 0.04mmol) in THF (ImI). The reaction mixture was refluxed with stirring for 15 h. The residue was extracted with chloroform, washed with water, dried over MgSO ₄ and the solvent was removed in vacuum to give 59. ¹ H NMR (CD ₃ OD): δ 1.21 (m, 12H), 2.01 (m, 15H), 4.20 (m, 8H). ³¹ P NMR (D ₂ O): δ 59.0.

5-[((3-Amino-3-carboxy)propyI)(hydroxy)phosphinyl]pentanoic Acid (60). 190mg of 59 was treated with 2 ml of 8N HCl and refluxed for 15 h. The reaction mixture was concentrated under vacuum and the residue was purified using Dowex AG50x4 cation exchange resin column (H ⁺ , 20-50 mesh, 24x1.7 cm, water elution). The fractions which gave positive color reaction with ninhydrine were combined and evaporated under vacuum to give 60. ¹ H NMR (D ₂ O): δ 1.66 (m, 8H), 2.09 (m, 2H), 2.06 (m, 2H), 2.38 (t, J=7.2 Hz, 2H), 3.94 (t, J= 5.93 Hz, IH). ³¹ P NMR (D ₂ O): δ 60.58.

Scheme 20 ^a

"Reagents and conditions : (a) 4-nitrobenzaldehyde, CH ₂ Cl ₂ , BSA, 2Oh; (b) 6N HCl, reflux, 5h; (c) 4- methylsulphonyl benzaldehyde, CH ₂ Cl ₂ , BSA, 15h; (d) 6N HCl, reflux, 3h

(35)-4-[(((3-(iV-BenzyloxycarbonyI)ainino-3-methoxycarbonyl) propyl) (hydroxy) phos- phinyl)-hydroxymethyl] nitrobenzene (71). The compound was prepared from 5 (0.8mmol) and 4-nitrobenzaldehyde (302mg, 2mmol) by using the procedure described for preparation of compound 15. ¹ H NMR (CD ₃ OD): δ 1.98 (m, 4H), 3.73 (s, 3H), 4.32 (m, IH), 5.12 (s, 2H), 5.19 (d, J=12.56 Hz, IH), 7.33 (m, 5H), 7.71 (m, 2H), 8.19 (d, J=8.32 Hz, 2H). ³¹ P NMR (CD ₃ OD): δ 48.26.

(3S)-4-[(((3-amino-3-carboxy)propyl)(hydroxy)phosphinyl)-hyd roxymethyl] nitrobenzene (72). The removal of the protecting groups in compound 71 was accomplished following the same procedure as that followed for compound 16 and purified by Dowex AG50x4 column to afford 72 (quantitative yield). ¹ H NMR (D ₂ O): δ 1.72 (m, 2H), 2.11 (m,

2H), 4.02 (m, IH), 4.97 (d, J=10.8 Hz, IH), 7.58 (d, J=7.43 Hz, 2H), 8.18 (d, J=8.64 Hz, 2H). ³¹ P NMR (D ₂ O): δ 49.43. ¹³ C NMR (D ₂ O): δ 22.79 (d, J=98.03 Hz), 23.57, 54.02, 73.05 (d, J-104.90 Hz), 123.89, 127.98, 146.45, 147.40, 172.27. Mass (ESI): 319.1 (M+l).

(3S)-4- [(((3-(N-Benzy loxy carbony l)amino-3-methoxy carbony l)propy 1) (hydroxy) phos- phinyl)-hydroxymethyl] methylsulphonylbenzene (73). The compound was prepared from 5 (O.Smmol) and 4-methylsulphonylbenzaldehyde (276mg, 1.5mmol) by following the procedure described for preparation of compound 15. ¹ H NMR (CD ₃ OD): δ 2.03 (m, 4H), 3.11 (s, 3H), 3.72 (s, 3H), 4.32 (m, IH), 5.12 (s, 2H), 5.14 (d, J=7.12 Hz, IH), 7.35 (m, 5H), 7.76 (d, J=7.31 Hz, 2H), 7.96 (d, J=8.17 Hz, 2H). ³¹ P NMR (CD ₃ OD): δ 48.37. ¹³ C NMR (CD ₃ OD): δ 22.10 (d, J=91.02 Hz), 24.19, 43.65, 52.20, 55.0I, 66.95, 71.87 (d, J=I 08.88 Hz), 127.28, 128.01, 128.28, 128.72, 137.10, 140.17, 144.50, 157.61, 172.86.

(35)-4-[(((3-amino-3-carboxy)propyl)(hydroxy)phosphinyl)-hyd roxymethyI] methylsulpho nylbenzene (74). The removal of the protecting groups in compound 73 was accomplished following the same procedure as that followed for compound 16 and purified by Dowex AG50x4 column to afford 74 (quantitative yield). ¹ H NMR (D ₂ O): δ 1.69 (m, 2H), 2.07 (m, 2H), 3.16 (s, 3H), 3.99 (m, IH), 4.93 (d, J=10.63 Hz, IH), 7.59 (d, J=8.31 Hz, 2H), 7.84 (d, J=8.33 Hz, 2H). ³¹ P NMR (D ₂ O): δ 49.72. ¹³ C NMR (D ₂ O): δ 21.69 (d, J=88.19 Hz), 22.87, 43.66, 53.21, 71.92 (d, J=107.75 Hz), 127.54, 128.26, 138.65, 143.91, 171.42.

Scheme 21 ^a

"Reagents and conditions : (a) 3,5-dinitrosalicylaldehyde, CH ₂ Cl ₂ , BSA, 15h; (b) 6N HCl, reflux, 3h; (c) 2- hydroxy 3-nitrobenzaldehyde, CH ₂ Cl ₂ , BSA, 15h; (d) 6N HCl, reflux, 3h

(3iS)-3-[(((3-(N-Benzyloxycarbonyl)amino-3-methoxycarbonyl)p ropyl) (hydroxy) phos- phinyl)-hydroxymethyl] 2-hydroxy-l,5-dinitrobenzene (75). The compound was prepared from 5 (0.8mmol) and 3,5-dinitrosalicylaldehyde (424mg, 2mmol) by using the procedure described for preparation of compound 15. ¹ H NMR (CD ₃ OD): δ 2.04 (m, 4H), 3.75 (s, 3H), 4.29 (m, IH), 5.07 (s, 2H), 5.55 (d, J=I 0.45 Hz, IH), 7.31 (m, 5H), 8.64 (m, IH), 8.88 (m, IH). ³¹ P NMR (CD ₃ OD): δ 48.38.

(3S)-3-[(((3-amino-3-carboxy)propyI)(hydroxy)phosphinyl)-hyd roxymethyl] 2-hydroxy- 1,5-dinitrobenzene (76). The removal of the protecting groups in compound 75 was accomplished following the same procedure as that followed for compound 16 and purified by Dowex AG50x4 column to afford 76 (quantitative yield). ¹ H NMR (D ₂ O): δ 1.84 (m, 2H), 2.18 (m, 2H), 4.04 (m, IH), 5.37 (d, J=8.28 Hz, IH), 8.57 (s, IH), 8.93 (s, IH). ³¹ P NMR

(D ₂ O): δ 49.52. ¹³ C NMR (D ₂ O): δ 23.39 (d, J=98.75 Hz), 23.65, 54.3, 67.2 (d, J=106.3 Hz), 121.67, 129.67, 132.29, 134.48, 139.74, 156.2, 172.39. Mass (ESI): 381.1 (M+l).

(3iS)-3-[(((3-(iV-Ben2yloxycarbonyl)amino-3-methoxycarbonyl) propyl) (hydroxy) phos- phinyl)-hydroxymethyl] 2-hydroxy-nitrobenzene (77). The compound was prepared from 5 (O.δmmol) and 2-hydroxy-3-nitrobenzaldehyde (334mg, 2mmol) by following the procedure described for preparation of compound 15. ¹ H NMR (CD ₃ OD): δ 1.96 (m, 4H), 3.73 (s, 3H), 4.29 (m, IH), 5.12 (s, 2H), 5.55 (d, J=7.89 Hz, IH), 7.08 (t, J=8.05 Hz, IH), 7.33 (m, 5H), 7.95 (d, J=7.45 Hz, IH), 8.06 (d, J=8.36 Hz, IH). ³¹ P NMR (CD ₃ OD): δ 48.74. ¹³ C NMR (CD ₃ OD): δ 21.76 (d, J=88.40 Hz), 24.20, 52.09, 55.04, 65.25 (d, J=I 11.58 Hz), 66.87, 119.89, 124.68, 127.88, 128.13, 128.58, 129.45, 134.32, 136.57, 137.07, 151.83, 157.62, 172.82.

(3S)-3-[(((3-amino-3-carboxy)propyl)(hydroxy)phosphinyl)-hyd roxymethyl] 2-hydroxy- nitrobenzene (78). The removal of the protecting groups in compound 77 was accomplished following the same procedure as that followed for compound 16 and purified by Dowex AG50x4 column to afford 78 (quantitative yield). ¹ H NMR (D ₂ O): δ 1.83 (m, 2H), 2.12 (m, 2H), 4.08 (m, IH), 5.34 (d, J=7.74 Hz, IH), 7.06 (t, J=8.14 Hz, IH), 7.78 (d, J=7.59 Hz, IH), 8.03 (d, J=8.50 Hz, IH). ³¹ P NMR (D ₂ O): δ 50.72. ¹³ C NMR (D ₂ O): δ 23.19 (d, J=89.51 Hz), 23.58, 53.9I, 66.31 (d, JH08.25 Hz), 120.45, 125.17, 129.22, 134.59, 136.51, 151.51, 172.41.

Scheme 22 ^a

^a Reagents and conditions : (a) pentafluoro benzaldehyde, CH ₂ Cl ₂ , BSA, 15h; (b) 6N HCl, reflux, 3h; (c) 2- hydroxy 5-nitrobenzaldehyde, CH ₂ Cl ₂ , BSA, 15h; (d) 6N HCl, reflux, 3h

(3S)-1-[(((3-(N-Benzyloxycarbonyl)amino-3-methoxycarbonyl)pr opyl) (hydroxy) phos- phinyl)-hydroxymethyl] 2,3,4,5,6-pentafluorobenzene (79). The compound was prepared from 5 (0.8mmol) and pentafluoro benzaldehyde (392mg, 2mmol) by using the procedure described for preparation of compound 15. ¹ H NMR (CD ₃ OD): δ 2.16 (m, 4H), 3.76 (s, 3H), 4.32 (m, IH), 5.12 (s, 2H), 5.34 (d, J=I 1.02 Hz, IH), 7.33 (m, 5H). ³¹ P NMR (CD ₃ OD): δ 47.51.

(3S)-1-[(((3-amino-3-carboxy)propyl)(hydroxy)phosphinyl)-hyd roxymethyl] 2,3,4,5,6- penta fluorobenzene (80). The removal of the protecting groups in compound 79 was accomplished following the same procedure as that followed for compound 16 and purified by Dowex AG50x4 column to afford 80 (quantitative yield). ¹ H NMR (D ₂ O): δ 1.86 (m, 2H),

2.13 (m, 2H), 4.07 (m, IH), 5.18 (d, J=10.68 Hz, IH). ³¹ P NMR (D ₂ O): δ 47.78. Mass (ESI): 364.1 (M+l).

(3<S)-3-[(((3-(N-Benzyloxycarbonyl)amino-3-methoxycarbony l)propyl) (hydroxy) phos- phinyl)-hydroxymethyl] 4-hydroxy-nitrobenzene (81). The compound was prepared from 5 (0.8mmol) and 2-hydroxy-5-nitrobenzaldehyde (334mg, 2mmol) by following the procedure described for preparation of compound 15. ¹ H NMR (CD ₃ OD): δ 2.05 (m, 4H), 3.72 (s, 3H), 4.30 (m, IH), 5.12 (s, 2H), 5.45 (d, J=7.41 Hz, IH), 6.96 (d, J=8.95 Hz, IH), 7.30 (m, 5H), 8.07 (m, IH), 8.47 (s, IH). ³¹ P NMR (CD ₃ OD): δ 49.56.

(3S)-3-[(((3-amino-3-carboxy)propyl)(hydroxy)phosphinyl)-hyd roxymethyl] 4-hydroxy- nitrobenzene (82). The removal of the protecting groups in compound 81 was accomplished following the same procedure as that followed for compound 16 and purified by Dowex AG50x4 column to afford 82 (quantitative yield). ¹ H NMR (D ₂ O): δ 1.83 (m, 2H), 2.09 (m, 2H), 3.98 (m, IH), 5.10 (d, J=8.22 Hz, IH), 6.83 (d, J=9.01 Hz, IH), 7.91 (d, J=8.93 Hz, IH), 8.16 (s, IH). ³¹ P NMR (D ₂ O): δ 51.73. ¹³ C NMR (D ₂ O): δ 20.90 (d, J=76.74 Hz), 21.51, 51.95 (d, J-13.02 Hz), 65.72 (d, J=108.25 Hz), 114.91, 122.96, 123.66, 124.20, 138.82, 158.63, 170.29. Mass (ESI): 335.1 (M+l).

Scheme 23 ^a

"Reagents and conditions : (a) 5-nitro-2-furaldehyde, CH ₂ Cl ₂ , BSA, 18h; (b) 6N HCl, 9O°C , 3h; (c) 5-nitro-2- thiophenecarboxaldehyde, CH ₂ Cl ₂ , BSA, 15h; (d) 6N HCl, 90°C , 3h

(35)-2-[(((3-(iV-Ben2yloxycarbonyl)amino-3-methoxycarbonyl)p ropyl) (hydroxy) phos- phinyl)-hydroxymethyl] 5-nitrofuran (83). The compound was prepared from 5 (O.Smmol) and 5-nitro-2-furaldehyde (282mg, 2mmol) by using the procedure described for preparation of compound 15. ¹ H NMR (CD ₃ OD): δ 2.07 (m, 4H), 3.73 (s, 3H), 4.32 (m, IH), 5.08 (d, J=15.98 Hz, IH), 5.11 (s, 2H), 6.80 (m, IH), 7.38 (m, 6H). ³¹ P NMR (CD ₃ OD): δ 46.14.

(35)-2-[(((3-amino-3-carboxy)propyl)(hydroxy)phosphinyl)-hyd roxymethyl] 5- nitrofuran (84). The removal of the protecting groups in compound 83 was accomplished following the same procedure as that followed for compound 16 and purified by Dowex AG50x4 column to afford 84 (quantitative yield). ¹ H NMR (D ₂ O): δ 1.86 (m, 2H), 2.19 (m, 2H), 4.12 (m, IH), 4.95 (d, J=I 1.96 Hz, IH), 6.73 (m, IH), 7.50 (d, J=3.69 Hz, IH). ³¹ P NMR (D ₂ O): δ 48.16. Mass (ESI): 307.1 (M+l).

(3S)-2-[(((3-(N-Benzyloxycarbonyl)amino-3-methoxycarbonyl)pr opyl) (hydroxy) phos- phinyl)-hydroxymethyl] 5-nitrothiophene (85). The compound was prepared from 5 (0.8mmol) and 5-nitro~2-thiophenecarboxaldehyde (314mg, 2mmol) by following the procedure described for preparation of compound 15. ¹ H NMR (CD ₃ OD): δ 2.08 (m, 4H), 3.72 (s, 3H), 4.30 (m, IH), 5.10 (m, 3H), 7.12 (m, IH), 7.34 (m, 5H), 7.89 (m, IH). ³¹ P NMR (CD ₃ OD): δ 46.65.

(3S)-2-[(((3-amino-3-carboxy)propyl)(hydroxy)phosphmyI)-hydr oxymethyl] 5-nitrothio phene (86). The removal of the protecting groups in compound 85 was accomplished following the same procedure as that followed for compound 16 and purified by Dowex AG50x4 column to afford 86 (quantitative yield). ¹ H NMR (D ₂ O): δ 1.78 (m, 2H), 2.14 (m, 2H), 4.02 (m, IH), 5.08 (d, J=I 1.11 Hz, IH), 7.06 (m, IH), 7.94 (d, J=4.30 Hz, IH). ³¹ P NMR (D ₂ O): δ 46.82. ¹³ C NMR (D ₂ O): δ 22.83 (d, J=93.34 Hz), 23.70, 53.89, 70.19 (d, J=106.74 Hz), 124.93, 130.71, 150.24, 153.80, 172.35. Mass (ESI): 323.1 (M-I).

Scheme 24 ^a

"Reagents and conditions : (a) 5-trifluoromethyl-2-furaldehyde, CH ₂ Cl ₂ , BSA, 15h; (b) 6N HCl, 90°C, 3h ; (c) 2,6-dinitrobenzaldehyde, CH ₂ Cl ₂ , BSA, 15h; (d) 6N HCl, 90°C, 3h

(3S)-3-[(((3-(N-Benzyloxycarbonyl)amino-3-methoxycarbonyl)pr opyl) (hydroxy) phos- phinyl)-hydroxymethyl] 5-trifluoromethyIfuran (87). The compound was prepared from 5 (0.8mmol) and 5-trifluoromethyl-2-furaldeh.yde (328mg, 2mmol) by using the procedure described for preparation of compound 15. ¹ H NMR (CD ₃ OD): δ 2.01 (m, 4H), 3.72 (s, 3H), 4.32 (m, IH), 5.03 (d, J=I 1.24 Hz, IH), 5.12 (s, 2H), 6.70 (m, IH), 6.94 (m, IH), 7.32 (m, 5H). ³¹ P NMR (CD ₃ OD): δ 46.79.

(3S)-2-[(((3-amino-3-carboxy)propyl)(hydroxy)phosphinyI)-hyd roxymethyl] 5- trifluorome thylfuran (88). The removal of the protecting groups in compound 87 was accomplished following the same procedure as that followed for compound 16 and purified by Dowex AG50x4 column to afford 88 (quantitative yield). ¹ H NMR (D ₂ O): δ 1.82 (m, 2H),

2.18 (m, 2H), 4.07 (m, IH), 4.85 (d, J=I 1.59 Hz, IH), 6.53 (m, IH), 6.59 (m, IH). ³¹ P NMR (D ₂ O): δ 48.29. ¹³ C NMR (D ₂ O): δ 23.11 (d, J=91.21 Hz), 23.41, 53.82 (d, J=13.90 Hz), 67.16 (d, J=109.70 Hz), 110.80, 113.74, 115.53 (q, J=266.26 Hz), 141.40 (q, J=43.59 Hz), 154.59, 172.09.

(3S)-2-[(((3-(N-Benzyloxycarbonyl)amino-3-methoxycarbonyl)pr opyI) (hydroxy) phos- pb.inyl)-hydroxymethyl] 1,3-dinitrobenzene (89). The compound was prepared from 5 (0.8mmol) and 2,6-dinitrobenzaldehyde (392mg, 2mmol) by following the procedure described for preparation of compound 15. ¹ H NMR (CD ₃ OD): δ 1.96 (m, 4H), 3.72 (s, 3H), 4.32 (m, IH), 5.11 (s, 2H), 6.27 (d, J=16.15 Hz, IH), 7.34 (m, 5H), 7.64 (m, IH), 7.97 (d, J=7.86 Hz, 2H). ³¹ P NMR (CD ₃ OD): δ 48.69.

(3 _* S)-2-[(((3-amino-3-carboxy)propyI)(hydroxy)phosphinyI)-hydro xymethyl] 1,3-dinitro benzene (90). The removal of the protecting groups in compound 89was accomplished following the same procedure as that followed for compound 16 and purified by Dowex AG50x4 column to afford 90 (quantitative yield). ¹ H NMR (D ₂ O): δ 1.87 (m, 2H), 2.12 (m, 2H), 4.03 (m, IH), 5.96 (d, J=I 1.57 Hz, IH), 7.64 (t, J=7.97, IH), 8.01 (d, J=6.70 Hz, 2H). ³¹ P NMR (D ₂ O): δ 48.28. ¹³ C NMR (D ₂ O): δ 23.80, 24.55 (d, J=93.91 Hz), 54.29, 69.17 (d, J=100.70 Hz), 128.81, 129.65, 149.49, 172.54. Mass (ESI): 364.1(M+1).

Scheme 2S ^a

"Reagents and conditions : (a) BH ₃ , THF, 2h; (b) (ClCO) ₂ , DMSO, TEA, CH ₂ Cl ₂ ; (c) CH ₂ Cl ₂ , BSA, 0.5h; (d) 6N HCl, 90°C, 3h

3-trifluoromethyl-4-nitrobenzyl alcohol (91). To a stirred solution of 3-trifluoromethyl-4- nitrobenzoic acid (3g) in 15 ml of tetrahydrofuran at O ⁰ C was added 1 M BH ₃ /THF (64 ml) dropwise under argon. This reaction mixture was allowed to stir at room temperature for 2h and quenched by saturated NaHCO ₃ . The solution was extracted with dichloromethane and then evaporated the organic layer to dryness in vacuo. The crude residue was purified on silica gel using cyclohexane:ethylacetate (90:10 to 60:40, gradient) as the eluent to afford 1.76 g of 91. ¹ HNMR (CD ₃ OD): δ 4.80 (s, 2H), 7.78 (d, J=8.33 Hz, IH), 4.91 (m, 2H).

3-trifluoromethyl-4-nitrόbenzaldehyde (92). Dichloromethane (7 ml) was cooled to -78°C in round bottom flak with septum under argon. Oxalyl chloride (0.49 ml) was added in one portion. Dimethyl sulfoxide (0.67ml) in dichloromethane (3.5ml) was added dropwise over Ih. 3-trifluoromethyl-4-nitrobenzyl alcohol 91 (1.04g) in dichloromethane (7ml) was added dropwise over Ih. The reaction mixture was stirred at -78°C for 45min. Triethylamine (2.6ml) was added over 45 min. TLC analysis indicated the reaction was complete. The reaction was quenched with 1 M aqueous potassium hydrogensulfate (50ml).the organic layer was washed with saturated NaHCO ₃ (5OmI), water (50ml), and brine (50ml). The organic layer was dried over magnesium sulphate, and concentrated in vacuo to afford the desired aldehyde 92. ¹ H NMR (CDCl ₃ ): δ 8.05 (d, JHL.2 Hz, IH), 8.28 (d, J=8.4 Hz, IH), 8.36 (s, IH), 10.18 (s, IH).

(35)-4-[(((3-(iV-Benzyloxycarbonyl)amino-3-methoxycarbonyl)p ropyl) (hydroxy) phos- phinyl)-hydroxymethyl] 2-trifluoromethyl-l-nitrobenzene (93). The compound was prepared from 5 (0.8mmol) and 3- trifluoromethyl-4-nitrobenzaldehyde (394mg, 1.8mmol) by following the procedure described for preparation of compound 15. ¹ H NMR (CD ₃ OD): δ 2.05 (m, 4H), 3.74 (s, 3H), 4.32 (m, IH), 5.11 (s, 2H), 5.18 (d, J=40.39 Hz, IH), 7.34 (m, 5H), 8.01 (m, 3H). ³¹ P NMR (CD ₃ OD): δ 47.70.

(35)-4-[(((3-amino-3-carboxy)propyl)(hydroxy)phosphinyl)-hyd roxymethyl] 2-trifluoro methyl-1-nitrobenzene (94). The removal of the protecting groups in compound 93 was accomplished following the same procedure as that followed for compound 16 and purified by Dowex AG50x4 column to afford 94 (quantitative yield). ¹ H NMR (D ₂ O): δ 1.79 (m, 2H), 2.14 (m, 2H), 4.03 (m, IH), 5.02 (d, J=I 0.85 Hz, IH), 7.82 (d, J=8.42 Hz, IH), 7.94 (s, IH), 8.02 (d, J=8.43 Hz, IH). ³¹ P NMR (D ₂ O): δ 48.33. Mass (ESI): 387.1 (M+l).

Scheme 26 ^a

"Reagents and conditions : (a) (ClCO) ₂ , DMSO, TEA, CH ₂ Cl ₂ ; (b) CH ₂ Cl ₂ , BSA, 0.5h; (c) 6N HCl, 9O°C, 3h

3,5-dinitrobenzaldehyde (95). The title compound was obtained from 3,5-dinitrobenzyl alcohol as yellow solid in a similar manner for the preparation of 92. ¹ H NMR (CDCI ₃ ): δ 9.04 (s, 2H) ₅ 9.22 (s, IH) ₅ 10.25 (s, IH).

(3.S)-3-[(((3-(N-Benzyloxycarbonyl)ainino-3-methoxycarbon yl)propyl) (hydroxy) phos- phinyl)-hydroxymethyl] 1,5-dinitrobenzene (96). The compound was prepared from 5 (O.δmmol) and 3,5-dinitrobenzaldehyde (392mg, 2mmol) by using the procedure described

for preparation of compound 15. ¹ H NMR (CD ₃ OD): δ 1.99 (m, 4H), 3.75 (s, 3H), 4.32 (m, IH), 5.10 (S, 2H), 5.29 (d, J=9.43 Hz, IH), 7.32 (m, 5H), 8.72 (s, 2H), 8.88 (s, IH). ³¹ P NMR (CD ₃ OD): δ 47.71. ¹³ C NMR (CD ₃ OD): δ 22.28 (d, J=92.43 Hz), 24.10, 52.19, 54.96, 66.92, 70.65 (d, J=108.91 Hz), 117.79, 127.30, 127.86, 128.15, 128.59, 136.98, 143.01, 148.60, 157.60, 172.83.

(35)-3-[(((3-amino-3-carboxy)propyl)(hydroxy)phosphinyl)-hyd roxymethyl] 1,5- dinitrobenz ene (97). The removal of the protecting groups in compound 96 was accomplished following the same procedure as that followed for compound 16 and purified by Dowex AG50x4 column to afford 97 (quantitative yield). ¹ H NMR (D ₂ O): δ 1.78 (m, 2H), 2.14 (m, 2H), 4.05 (m, IH), 5.08 (d, J=10.04 Hz, IH), 8.58 (s, 2H), 8.91 (s, IH). ³¹ P NMR (D ₂ O): δ 48.29. ¹³ C NMR (D ₂ O): δ 22.81 (d, J=91.46 Hz), 23.54, 53.84, 71.99 (d, J=104.79 Hz), 118.30, 127.49, 143.41, 148.37, 172.17. Mass (ESI): 364.0 (M+l).

Example 2: Synthesis of substituted benzaldehydes

A) Preparation of nitro-benzaldehydes from nitro-benzoic acids or nitro-benzyl alcohols

1) Reduction (step 1) - oxidation (step 2)

Reduction step: a) BH3-SMe2 (Aulenta JOC 05; Campbell TL03) b) BH3, THF (Campbell TL03; Liou JMC04; Parlow JMC03)

Oxidation step: a) PDC (Liou JMC04) b) PCC (Aulenta JOC05; Campbell TL03) c) oxidizing polymer (Sorg Angew 01) d) Swern (Campbell 03; Parlow JMC03) 2) one step reduction i) TMSCl ii) DiBAL-H (Chandrasekhar TL98)

This procedure was applied to the following alcohols or acids:

B) Substitutions of nitro-benzaldehydes

1) substitution with benzofurazans

benzofurazan

2) substitution with sulfonyl chlorides

other sulfonylchlorides can be used, for example

o-,

The following phosphinates can be synthesized using the aldehydes described above

R= NO ₂ Or SO ₂ NH ₂

Example 3: Experimental of hvpophosphorous acid derivatives according to Method B Scheme 27

Reagents and conditions: (a) reflux at 12O°C; (b) ethyl acrylate, 5O°C, 2h; (c) dibromoethane, reflux at 120°C, 5h; (d) CH(OEt) ₃ , reflux at 140°C; (e) diethylacetamidomalonate, K ₂ CO ₃ , tetrabutylammonium bromide in THF, reflux ; (f) SN HCl, reflux, 15h

3-[(2-Bromoethyl)(ethoxy)phosphinyl)]propanoic Acid Ethyl Ester (1). A mixture of ammonium hypophosphite (4g, 48mmol) and hexamethydisilazane (7.73g, 48mmol) was heated at 12O ⁰ C for one hour under argon. After the mixture was cooled to 0 ⁰ C , ethyl acrylate (4.8g, 48mmol) was carefully added dropwise and the resulting mixture was stirred at 50 ⁰ C for 2h. Then the mixture was cooled to room temperature, dibromoethane (20ml) was added and stirred for 5h at 120 ⁰ C. The formed trimethylbromosilane and excess dibromoethane were removed under vacuum. Then 50 ml of aqueous ethanol (1:1) were added dropwise to the residue and refluxed for 0.5 h. Then the solvent was removed under vacuum and extracted with ethyl acetate. The organic layer was dried over MgSO ₄ and the solvent was removed in vacuum to give 1 (5.42g, 41.4%). ¹ H NMR (CD ₃ OD): δ 1.25 (t, J= 7.1 Hz, 3H) ₃ 2.06 (m, 2H), 2.42 (m, 2H), 2.61 (m, 2H) ₃ 2.61 (m, 2H) ₃ 4.14 (q, J= 7.1 Hz ₃ 2H). ³¹ P NMR (CD ₃ OD): 6 49.5.

3-[Ethoxy(vinyI)phosphinyl]propanoic Acid Ethyl Ester (2). 5.42g of 1 (19.9mmol) were treated with 40ml of triethyl orthoformate, and the mixture was refluxed with a Dean-Stark trap to remove ethanol and ethyl formate. Excess of triethylorthoformate was removed in vacuo to give 2a+2b ([39.5:60.5], 5.91g).2b: ¹ H NMR (CD ₃ OD): δ 1.27 (m, 6H), 2.18 (m, 2H), 2.57 (m, 2H), 4.10 (m, 4H), 6.36 (m, 3H). ³¹ P NMR (CD ₃ OD): δ 44.9.

3-[((3-(iV-AcetyI)aiiiino)-3-(bisethoxycarbonyl)propyl)(etho xy)phosphinyI]propanoic Acid Ethyl Ester (3). Compound 2 (500mg, 0.9:lmmol[a:b]) was mixed with diethylacetamidomalonate (453mg, 2.1mmol), potassium carbonate (573 mg, 4.2mmol) and tetrabutylammonium bromide (32.2mg, O.lmmol) in THF (2ml). The reaction mixture was refluxed with stirring for 15 h. The residue was extracted with chloroform, washed with water, dried over MgSO ₄ and the solvent was removed in vacuum to give 3 (564mg, 67.9%). The residue was purified by column chromatography (Silica gel 60, EtOAc/MeOH, 1:0 to 8:2) to afford 3 (507mg). ¹ H NMR (CD ₃ OD): δ 1.31 (m, 12H), 1.75 (m, 2H), 2.05 (s, 3H), 2.16 (m, 2H), 2.59 (m, 4H), 4.17 (m, 8H). ¹³ C NMR (CD ₃ OD): δ 13.5, 16.1, 21.6, 22.4 (d, J= 101 Hz), 22.9 (d, J= 93 Hz), 25.8, 26.7, 60.5, 61.1, 62.7, 66.8 (d, J= 17 Hz), 167.6, 171.4, 172.5 (d, J= 14 Hz). ³¹ P NMR (CD ₃ OD): δ 58.1.

3-[((3-Amino-3-carboxy)propyl)(hydroxy)phosphinyl]propanoic Acid (4). 210mg of 4 (0.48mmol) was treated with 2 ml of 8N HCl and refluxed for 15 h. The reaction mixture was concentrated under vacuum and the residue was purified using Dowex AG50x4 cation exchange resin column (H ⁺ , 20-50 mesh, 24x1.7 cm, water elution). The fractions which gave positive color reaction with ninhydrine were combined and evaporated under vacuum to give 5 (95mg, 82.8%). ¹ H NMR (D ₂ O): δ 1.66 (m, 2H), 1.85 (m, 2H), 2.06 (m, 2H), 2.51 (m, 2H), 3.96 (t, J= 5.7 Hz, IH). ¹³ C NMR (D ₂ O): δ 23.5, 24.3 (d, J= 91 Hz), 25.0 (d, J= 91 Hz), 27.3, 54.1 (d, J= 15 Hz), 172.6, 177.5 (d, J= 15 Hz). ³¹ P NMR (D ₂ O): δ 57.4. MS (ESI): m/z 238.1 (M-I). Anal. (C ₇ Hi ₄ NO ₆ P. 0.25H ₂ O) C, H, N.

Scheme 28

Reagents and conditions: (a) reflux at 120°C; (b) diethyl maleate, 50°C, 2h; (c) dibromoethane, reflux at 120°C; (d) CH(OEt) ₃ , reflux at 140°C; (e) diethylacetamidomalonate, K ₂ CO ₃ , tetrabutylammonium bromide in THF, reflux ; (f) 8N HCl, reflux

2-[((2-Bromoethyl)(hydroxy)-phosphinyI)methyl]butane-l,4- dioic Acid Ethyl Ester (8).

The compound was prepared from diethyl maleate by a procedure similar to that for the preparation of compound 1 (oily liquid, 1.2Ig, 35% yied); ¹ H NMR (CD ₃ OD): δ 1.26 (m, 6H), 2.58 (m, 2H), 2.91 (m, 2H), 3.50 (m, IH), 3.66 (m, 2H), 4.20 (m, 4H). ³¹ P NMR (CD ₃ OD): δ 41.9.

2-[(((3-(iV-AcetyI)amino)-3-(bisethoxycarbonyl)propyl)(ethox y)phosphinyl)methyI]butane-l,4- dioic Acid Ethyl Ester (10). Compound 8 was esterified by triethylorthoacetate by a procedure similar to that for the preparation of compound 2 (oily liquid, 1.36g); ³¹ P NMR (CD ₃ OD): δ 37.8, 48.1 (9a and 9b). The residue (Ig) was used for the next step procedure similar to that of compound 3 without further purification. (77.1% yield over two steps); ¹ H NMR (CD ₃ OD): δ

1.33 (m, 15H) ₅ 1.88 (m, 2H), 2.07 (s, 3H), 2.57 (m, 2H), 2.92 (m, 2H), 3.56 (m, IH), 4.22 (m, 10H). ³¹ P NMR (CD ₃ OD): δ 51.7. 52.2 (1 :1). MS (ESI): m/z 508.1 (M-I).

2-[(((3-amino-3-carboxy)propyl)(hydroxy)phosphinyl)-methyl]b utane-l,4-dioic Acid (11). The removal of the protecting groups in compound 10 (186mg, 0.37mmol) was accomplished using the same procedure as that used for compound 4 to afford 11. The residue was purified by anion exchange chromatography. The residue was dissolved in freshly boiled and cooled water (0.2L), then pH adjusted to 9-10, and the solution deposited on a AGlχ4 resin (HCOO ^" , 200-400 mesh, 8.5x1 cm). The resin was washed with boiled water and the compound 10 was eluted with 0.72-0.73 M HCOOH (83mg, 80% yied). ¹ H NMR (D ₂ O): δ 1.78 (m, 2H), 2.14 (m, 2H), 2.81 (m, 2H), 3.18 (m, IH), 4.05 (t, J= 5.9 Hz, IH). ¹³ C NMR (D ₂ O): δ 23.4, 24.7 (d, J= 96 Hz), 30.9, 45.0 (d, J= 77 Hz), 53.7 (d, J= 15 Hz), 172.0, 174.4, 176.2 (d, J= 15 Hz). ³¹ P NMR (D ₂ O): δ 46.5.

Scheme 29

Reagents and conditions: (a) reflux at 120°C; (b) ethyl acrylate, 50°C, 2h; (c) acetamidoacrylic acid, 6O°C, 4h; (d) 2N HCl, MeOH, 80°C, 0.5h; (e) SN HCl, reflux

3- [(((2-(iV- Acetyl)ammo)-2-carboxy)propyl)(hy droxy)phosphinyl] propanoic Acid Ethyl Ester (12). A mixture of ammonium hypophosphite (498mg, 6mmol) and hexamethydisilazane (966g, 6mmol) was heated at 120 ⁰ C for one hour under argon. After the

mixture was cooled to O ⁰ C, ethyl acrylate (350mg, 3.5mmol) was carefully added dropwise and the resulting mixture was stirred at 50 ⁰ C for 2h. Then the mixture was cooled to room temperature, acetamidoacrylic acid (387mg, 3mmol) was added and stirred for 5h at 65 ⁰ C. A sample was taken from the reaction mixture and treated with one drop of 2N HCl and CD ₃ OD. ¹ H NMR (CD ₃ OD): δ 1.28 (t, J= 7.1 Hz, 3H), 2.02 (s, 3H), 2.12 (m, 2H), 2.36 (m, 2H), 2.62 (m, 2H), 4.18 (q, J= 7.1 Hz, 2H), 4.72 (m, IH). ³¹ P NMR (CD ₃ OD): δ 48.7.

3-[(((2-(iV-Acetyl)amino)-2-methoxycarbonyl)propyl)(hydroxy) phosphinyl]propanoic Acid Methyl Ester (13). 10 ml of 2N HCl was added dropwise to the above residue and extracted with ethylacetate. The aqueous part was evaporated to dryness, then 50 ml of methanol were added and the solvent was removed at 5O ⁰ C under vacuum to afford 13 (645mg, 73% yield over three steps). ¹ H NMR (CD ₃ OD): δ 2.08 (s, 3H), 2.14 (m, 2H), 2.43 (m, 2H), 2.65 (m, 2H), 3.71 (s, 3H), 3.76 (s, 3H), 4.80 (m, IH). ³¹ P NMR (CD ₃ OD): δ 51.8.

3-[((2-amino-2-carboxy)propyl)(hydroxy)phosphinyl]propanoic Acid (14). The removal of the protecting groups in compound 13 (525mg, 1.78mmol) was accomplished following the same procedure as that followed for compound 4 to afford 14. Compound 14 was purified by a Dowex AG50x4 column as described earlier (quantitative yied). ¹ H NMR (D ₂ O): δ 1.93 (m, 2H), 2.06 (m, IH), 2.32 (m, IH), 2.56 (m, 2H), 4.19 (m, IH). ¹³ C NMR (D ₂ O): δ 25.3 (d, J= 96 Hz), 27.3, 29.4 (d, J= 86 Hz), 49.3, 172.0, 177.3. ³¹ P NMR (D ₂ O): δ 52.0. MS (ESI): m/z 224.1 (M-I).

Example 4: Synthesis of Oxophosphonates

The α-hydroxyphosphinates described above may be oxidized to α-oxophosphinates usind PDC (pyridinium dichromate) (see P. Vayron et al. Chem. Eur. J. 2000, 6, 1050)

^oxidation ». PDC

Example 5: Synthesis of Sulfonates

Sulfides were oxidized to sulfones using oxone. Examples are given below.

1) oxone

2) deprotection

Example 6: Separation of α-hydroxyphosphinate diastereoisomers

Substituted hydroxymethyl phosphinates as 22, 24, etc. are mixtures of diastereoisomers. They were separed by HPLC using a reverse phase column (see for example Liu et al. J.Organometal. Chem. 2002, 646, 212) or a chiral anion exchange column (Chiralpack QD- AX (Daicel), see Lammerhofer et al. Tetrahedron Asym. 2003, 14, 2557). Separation of 50 and 56 was achieved on a Crownpack column (Daicel).

Example 7: Cyclic phosphinate synthesis

Scheme 30

5

. 1 ) RCOCI or oxalyl chloride

2) NaBH4 lequiv i 3) Swern oxydation

1 ) Strecker reaction

2) HCI 8N reflux

The glutaric α, γ-dimethylene diester was prepared according to Basavaiah et al. J. Org. Chem. 2002, 67, 7135

Substitutions were introduced in the starting glutaric α, γ-dimethylene diester according to Saxena et al. Synlett 2003, 10, 1439.

Example 8: Derivatives with an α, β cyclic aminoacid group

74

Example 9: Synthesis of α-alkyl vinylglycine

Hydroxy alky lation of imidazolidinones and oxazolidinones (5, 6) derived from methionine with acetaldehyde cleanly afforded a single diastereoisomer but hydrolysis only lead to side products. However the reaction was successful with alkyl substitution: the imidazolidinone derived from methionine was converted to the vinylglycine derivative by oxidation and subsequent pyrolysis of the sulfoxide. Deprotonation of this compound followed by reaction with alkyl halides as electrophiles, cleanly afforded α-alkyl vinyl imidazolidinone which was subsequently hydrolysed (6N HCl, 100 ⁰ C) to the corresponding α-alkylated vinylglycines (Scheme 31). These compounds can be also obtained by first α-alkylation of imidazolidinones derived from methionine, and then oxidation and subsequent pyrolysis of the sulfoxide (8) (scheme 32). In this latter case diastereoisomeric excess are higher.

D LDA ^{EX de %} 2) EX _{6N Hc| δ Me)} ^AllylBr I ⁹ BenzylBr 87

Scheme 31

Scheme 32

Milder hydrolysis conditions are required with oxazolidinones intermediates. This approach was used by Acton and Jones starting with D-Methionine (9). The ratio of diastereoisomeric alkyl oxazolidinone was only 88:12 and the major cis isomer could only be purified by RP HPLC. Alkylation yield was only about 50%.

KHMDS

purification RP HPLC

Scheme 33

A similar methodology was recently used by Annedi et al.(lθ) for the synthesis of α- alkylhomoserine and could be used for α-alkylvinylglycine preparation (Scheme 34).

arable mixture

Scheme 34

L-α-benzyl vinyl glycine may be obtained from D-Phe according to the procedure described by Cheng et al (11) (Scheme 35). A similar synthesis was carried out starting with N- protected phenylglycine (12).

Cbz-D-α-benzylvinylglycine methyl ester

Scheme 35

The bis-lactim methodology developed by Schδllkopf has been also used for the preparation of substituted L-vinylalanine (6, 13) (Scheme 36).

R"=H,Me,Phe

Scheme 36

Other synthesis are reviewed and described in (6).

One possible synthesis for Cbz-L-α-alkylvinylglycine methyl ester is the following:

1) NaOH/THF 1) H ₂ O ₂ /AcOH

2) HCI/MeOH 2) xylene, δ

Example 10: Pharmacological results

Agonist activity of the compounds was tested on HEK293 cells transiently transfected with rat mGlu4 expressing plasmid pRKG4 and chimeric G-protein Gqi9 by electroporation, as described by Gomeza, J. et al, MoI. Pharmacol; 1996, 50, 923-930.

Cells were plated in 96-well culture plates and labeled overnight with [ ³ H]myoinositol. The day after, cells were washed three times with Krebs buffer, incubated for 10 min with LiCl 5mM, and then incubated for 30 min in the absence (basal) or in the presence of the indicated compounds at InM up to lOOOμM. The total amount of [ ³ H]phosphatidylinositol accumulated in the cells was determined after Dowex purification as previously by Goudet C, et al, Prod. Natl. Acad. Sd. USA 2004, 101, 378-383.

The response dosis curves were adjusted by using equatrier y ⁼ [(Ymax-y min)/(l+(x/EC5o) ⁿ )]+ymin where EC50 is the concentration necessary for obtaining half of the maximal effect and n is Hill coefficient.

Results obtained with (3i?)-PCEP and (3.KS)-PCEP concerning the mGlu4, mGluθ, mGlu7 and mGluS receptors of group III are given in Table 1 and figures 1A-1E.

Table 1

Results obtained with other compounds according to the invention are given in Table 2

Table 2

CS 158 and CS 159 (33-34) are each a mixture of diastereoisomers.

Antagonist activity of the compounds was tested on HEK293 cells transiently transfected with rat mGlu4 expressing plasmid pRKG4 and chimeric G-protein Gqi9 by electroporation, as described in (14)

Cells were plated in 96-well culture plates and labeled overnight with [3H]myoinositol. The day after, cells were washed three times with Krebs buffer, incubated for 10 min with LiCl 5mM, then pre-incubated for 5 min in the presence of the compounds at from 1 nM up to 1000 μM tested as an antagonist, and then incubated for 30 min in the presence or the absence of the agonist (L- AP4 from 0.1 to 100 μM, depending on the receptor tested mGlu4(L-AP4 30OnM), niGluθ, mGlu7, mGlu8). Incubation was stopped by replacing the stimulation buffer by a solution of formic acid 0.1 M. The total amount of [3H]phosphatidylinositol accumulated in the cells was determined after Dowex purification as previously described in (15).

The response dosis curves were adjusted by using equatrier y =[(Ymax-y min)/(l+(χ/EC50)n)]+ymin where IC50 is the concentration necessary for obtaining half of the maximal inhibitory effect and n is Hill coefficient.

The derivatives of the invention with antagonist properties are particularly useful for treating pathologies such as ADHD (Attention Deficit and Hyperactivity Disorder) and the so-called affective pathologies such as nervous breakdown and/or bipolar disorders (depressions followed by over excitation) and psychotic syndromes.

References

(1) Afzali-Ardakani, A.; Rapoport, H. L-Vinylglycine. J.Org.Chem. 1980, 45, 4817- 4820.

(2) Olsen, J. A.; Severinsen, R.; Rasmussen, T. B.; Hentzer, M.; Givskov, M.; Nielsen, J. Synthesis of new 3- and 4-substituted analogues of acyl homoserine lactone quorum sensing autoinducers. Bioorg. Med. Chem. Lett. 2002, 12, 325-328.

(3) Krol, W. J.; Mao, S. S.; Steele, D. L.; Townsend, C. A. Stereochemical correlation of proclavaminic acid and syntheses of erythro- and threo-L-β-hydroxyornithine from an improved vinylglycine synthon. J. Org. Chem. 1991, 56, 728-731.

(4) Berkowitz, D. B.; Charette, B. D.; Karukurichi, K. R.; McFadden, J. M. α-vinylic amino acids: occurrence, asymmetric synthesis, and biochemical mechanisms. Tetrahedron: Asymmetry 2006, 17, 869-882.

(5) Cativiela, C; Diaz-de-Villegas, M. D. Stereoselective synthesis of quaternary α-amino acids. Part 1: Acyclic compounds. Tetrahedron: Asymmetry 1998, 9, 3517-3599.

(6) Berkowitz, D. B.; Chisowa, E.; McFadden, J. M. Stereocontrolled synthesis of quaternary β,γ-unsaturated amino acids: chain extension of- and -α-(2- tributylstannyl)vinyl amino acids. Tetrahedron 2001, 57, 6329-6343.

(7) Seebach, D.; Juaristi, E.; Miller, D. D.; Schickli, C; Weber, T. Addition of chiral glycine, methionine, and vinylglycine enolate derivatives to aldehydes and ketones in the preparation of enantiomerically pure -amino-hydroxy acids. Helv.Chim.Acta 1987, 70, 237-261.

(8) Weber, T.; Aeschimann, R.; Maetzke, T.; Seebach, D. Methionin als Vorlaufer zur enantioselektiven Synthese -verzweigter Vinylglycine und anderer Aminosauren. Helv.Chim.Acta 1986, 69, 1365-1377.

(9) Acton, J. J.; Jones, A. B. Synthesis and derivatization of a versatile α-substituted lactam dipeptide isostere. Tetrahedron Lett. 1996, 37, 4319-4322.

(10) Annedi, S. C; Biabani, F.; Poduch, E.; Mannargudi, B. M.; Majumder, K.; Wei, L.; Khayat, R.; Tong, L.; Kotra, L. P. Engineering D-amino acid containing novel protease inhibitors using catalytic site architecture. Bioorg. Med. Chem. 2006, 14, 214-236.

(11) Cheng, H.; Keitz, P.; Jones, J. B. Design and synthesis of a conformationally restricted cysteine protease inhibitor. J Org. Chem. 1994, 59, 7671-7676.

(12) Ma, D.; Zhu, W. Synthesis of (φ-α-cyclopropyM-phosphonophenylglycme. J. Org. Chem. 2001, 66, 348 - 350.

(13) Groth, U.; Schδllkopf, U.; Chiang, Y.-C. Asymmetric syntheses via heterocyclic intermediates; XIIIl. Enantioselective synthesis of (R)-α-alkenylalanine methyl esters using L-valine as chiral auxiliary reagent. Synthesis 1982, 864-866.

(14) Gomeza, J. et al, MoL Pharmacol; 1996, 50, 923-930.

(15) Goudet C, et al, Prod.Natl. Acad. Sci. USA 2004, 101, 378-383.