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NOVEL COMPOUNDS M \ S

The present invention relates to adenine derivatives, processes for their preparation, pharmaceutical compositions containing them and their use in therapy.

The immune system is comprised of innate and acquired immunity, both of which work cooperatively to protect the host from microbial infections. It has been shown that innate immunity can recognize conserved pathogen-associated molecular patterns through toll-like receptors (TLRs) expressed on the cell surface of immune cells. Recognition of invading pathogens then triggers cytokine production (including interferon alpha(IFNα)) and upregulation of co-stimulatory molecules on phagocytes, leading to modulation of T cell function. Thus, innate immunity is closely linked to acquired immunity and can influence the development and regulation of an acquired response.

TLRs are a family of type I transmembrane receptors characterized by an NH2-terminal extracellular leucine-rich repeat domain (LRR) and a COOH-terminal intracellular tail containing a conserved region called the Toll/IL-1 receptor (TIR) homology domain. The extracellular domain contains a varying number of LRR, which are thought to be involved in ligand binding. Eleven TLRs have been described to date in humans and mice. They differ from each other in ligand specificities, expression patterns, and in the target genes they can induce.

Ligands which act via TLRs (also known as immune response modifiers (IRMS)) have been developed, for example, the imidazoquinoline derivatives described in US Patent No. 4689338 which include the product Imiquimod for treating genital warts, and the adenine derivatives described in WO 98/01448 and WO 99/28321.

This patent application describes a class of 9-substituted-8-oxoadenine compounds having immuno-modulating properties which act via TLR7 that are useful in the treatment of viral or allergic diseases and cancers.

In accordance with the present invention, there is therefore provided a compound of formula (I)

wherein .1 R represents hydrogen, hydroxyl, or a Cj-Cg alkoxy, C2-C5 alkoxycarbonyl,

Cj-Cg haloalkyl, Cj-Cg haloalkoxy, Cg-Cjo aryl, C5-C10 heteroaryl or Cβ-Cg cycloalkyl group, each group being optionally substituted by one or more substiruents independently selected from halogen, hydroxyl, a Cj-Cg alkyl, Cj-Cg haloalkyl, Cj-Cg alkoxy,

Cj-Cg haloalkoxy, C2-C5 alkoxycarbonyl, amino (NH2), (mono)- Cj-Cg alkylamino and (di)-Cj-Cg alkylamino group;

Y represents a single bond or Cj-Cg alkylene;

X represents a single bond, an oxygen, sulphur atom, sulphonyl (S O2) or NR ;

Z represents a C2-Cg alkylene or C3-C8 cycloalkylene group, each group being optionally substituted by at least one hydroxyl;

2 4 X represents NR ;

Y represents a single bond or Cj-Cg alkylene;

3

Y represents a single bond or Cj-Cg alkylene; n is an integer 0, 1 or 2;

R represents halogen or a Cj-Cg alkyl, Cj-Cg hydroxyalkyl, Cj-Cg haloalkyl, Cj-Cg alkoxy, Cj-Cg hydroxyalkoxy, Cj-Cg haloalkoxy, amino (NH2), (mono)- Cj-Cβ alkylamino, (di)-Cj-Cg alkylamino group or a C3-C _§ saturated heterocyclic ring

comprising a ring nitrogen atom and optionally one or more further heteroatoms independently selected from nitrogen, oxygen and sulphur, the heterocyclic ring being optionally substituted by one or more substituents independently selected from halogen, hydroxy 1, oxo, CJ-CO alkyl, Cj-Cg alkoxy, C2-C5 alkylcarbonyl and C2-C5 alkoxycarbonyl;

2 R represents hydrogen or a Cj-Cg alkyl, C2-C6 alkenyl, C2-C6 alkynyl or

C ₃ -Cg cycloalkyl group, each group being optionally substituted by one or more substituents independently selected from halogen, hydroxyl or a Cj-Cg alkoxy, C2-CJ0 acyloxy, amino

(NH2), (mono)- Cj-Cg alkylamino, (di)-Cj-Cg alkylamino group and a C3-C8 saturated heterocyclic ring comprising a ring nitrogen atom and optionally one or more further heteroatoms independently selected from nitrogen, oxygen and sulphur, the heterocyclic ring in turn being optionally substituted by one or more substituents independently selected from halogen, hydroxyl, oxo, Cj-Cg alkyl, Cj-Cg alkoxy, C2-C5 alkylcarbonyl and C2-C5 alkoxycarbonyl group;

3 R represents hydrogen or Cj-Cg alkyl;

R ⁴ represents CO ₂ R ⁵ , SO ₂ R ⁵ , COR ⁵ , SO ₂ NR ⁶ R ⁷ and CONR ⁶ R ⁷ ;

R independently represents

(i) a 3- to 8-membered heterocyclic ring containing 1 or 2 heteroatoms comprising ring group NR , S(0) _m or oxygen, each ring may being optionally substituted by one or more substituents independently selected from halogen, hydroxyl or a Cj-Cg alkyl and Cj-Cg alkoxy group, or

(ii) a Cg-Cjo aryl or C5-CJ0 heteroaryl group, each of which may be optionally substituted by one or more substituents independently selected from halogen, cyano, Cj-Cg alkyl, C ₁ -C ₃ haloalkyl, carboxyl, S(O) _1n R ⁹ , OR ¹⁰ , CO ₂ R ¹⁰ , SO ₂ NR ¹⁰ R ¹ ^ CONR ¹⁰ R ¹¹ , NR ¹⁰ R ¹¹ , NR ¹⁰ SO ₂ R ⁹ , NR ¹⁰ CO ₂ R ⁹ , NR ¹⁰ COR ⁹ , or

(iii) a Ci-Cg alkyl, C ₂ -Cg alkenyl, C ₂ -Cg alkynyl or C3-C8 cycloalkyl group, each of which may be optionally substituted by one or more substituents independently selected from halogen, CN, C ₃ -C ₈ cycloalkyl, S(O) _p R ¹² , OR ¹³ , COR ¹³ , CO ₂ R ¹³ , SO ₂ NR ¹³ R ¹⁴ , i ς λ λ λ 'l 14 I Q T 9 I Q 1 9 λ 7. 1 9 I 'l 19

CONR R , M R , NR SO ₂ R , NR CO ₂ R , NR COR , NR SO ₂ R or a Cg-Cio ^ar yl ^or C5-C10 heteroaryl group or a heterocyclic ring, the latter three groups may be optionally substituted by one or more substituents independently selected from Ci-Cg alkyl (optionally substituted by hydroxy, Ci-Cg alkoxy, Ci-Cg alkoxycarbonyl, amino, Ci-Cg alkylamino, di-Ci-Cg alkylamino, amido, Ci-Cg alkylamido, di-Ci-Cg alkylamido, -OCH ₂ CH ₂ OH, pyrrolidinyl, pyrrolidinylcarbonyl, furanyl, piperidyl, methylpiperidyl or phenyl), Ci-Cg alkenyl (optionally substituted by phenyl), halogen, hydroxy, cyano, carboxy, amino, Ci-Cg alkylamino, di-Ci-Cg alkylamino, amido, Ci-Cg alkylamido, di-Ci-Cg alkylamido, Ci-Cg alkoxycarbonyl,

Ci-Cg alkylsulphonyl, Ci-Cg alkylcarbonylamino, Ci-Cg alkylcarbonylmethylamino, phenyl (optionally substituted by hydroxy, fluoro or methyl), pyrrolidinyl, pyridyl, piperidinyl, benzothiazolyl or pyrimidinyl;

R represents hydrogen or a Ci-Cg alkyl, C ₂ -Cg alkenyl, C ₂ -Cg alkynyl, C ₃ -Cg cycloalkyl group or heterocyclic ring, each of which may be optionally substituted by one or more substituents independently selected from halogen, hydroxyl, oxo, cyano, Ci-Cg alkyl,

C ₂ -C ₆ alkenyl, C ₂ -C ₆ alkynyl, C ₃ -C ₈ cycloalkyl, OR ¹⁵ , S(O) _q R ¹⁵ , CO ₂ R ¹⁶ , COR ¹⁶ , NR ¹⁶ R ¹⁷ , CONR ¹⁶ R ¹⁷ , NR ¹⁶ COR ¹⁷ , NR ¹⁶ CO ₂ R ¹⁵ , SO ₂ NR ¹⁶ R ¹⁷ , NR ¹⁶ SO ₂ R ¹⁵ , or a Cg-Cio ^ar yl ^or C5-C10 heteroaryl group or heterocyclic ring, the latter three groups being optionally substituted by one or more substituents independently selected from, Ci-Cg alkyl,

C ₃ -C ₈ cycloalkyl, halogen, S(O) _q R , CO ₂ R , COR , hydroxy or cyano; and

7 R represents hydrogen, a Ci-Cg alkyl, C ₂ -Cg alkenyl, C ₂ -Cg alkynyl, or C ₃ -C ₈ cycloalkyl group, each group may be optionally substituted by one or more

substituents independently selected from halogen, C3-C8 cycloalkyl, a C ₆ -Ci ₀ aryl or C5- Cio heteroaryl group, carboxy, cyano, OR , hydroxy or NR R , or

R and R together with the nitrogen atom to which they are attached form a 3- to 8- membered saturated or partially saturated heterocyclic ring, optionally containing further heteroatoms or heterogroups selected from nitrogen, S(O) _m or oxygen. The heterocyclic ring, may be optionally substituted by one or more substituents independently selected from

90 91 99 93 94 94 halogen, hydroxy., carboxyl, cyano, OR , NR R ₁ S(O) _q R , COR , CO ₂ R ,

94 95 94 95 94 93

NR ^/4 R , CONR R , NR SO ₂ R , C ₆ -C ₁₀ aryl , C5-C10 heteroaryl group, heterocyclic ring, Ci-C ₆ alkyl, C ₂ -C ₆ alkenyl, C ₂ -C ₆ alkynyl or C ₃ -Cg cycloalkyl group, the latter seven groups being optionally substituted by one or more substituents independently selected from halogen, hydroxyl, oxo,

90 93 94 94 94 95 94 95 94 93 cyano, OR , S(O) _q R , COR , CO ₂ R , NR R , CONR R , NR CO ₂ R ,

24 25 24 25 24 93

NR COR , SO ₂ NR R , NR SO ₂ R , a heterocyclic ring or a C ₆ -Ci ₀ aryl or C ₅ -Ci ₀ heteroaryl group, the latter three groups being optionally substituted by one or more substituents independently selected from Ci-C ₆ alkyl, halogen, hydroxy or cyano;

R ⁸ represents hydrogen, CO ₂ R ²⁶ , COR ²⁶ , SO ₂ R ²⁶ , Ci-C ₆ alkyl or C ₃ -C ₆ cycloalkyl group, each group may be optionally substituted by one or more substituents independently

97 9R selected from halogen, hydroxyl, and NR R ;

„ 10 ,, 11 _Ώ 16 ,, 17 ^ 18 _, 19 -.21 _Ώ 22 ,,26 „27 „28 „29 „30 , . , , .. R , R , R , R , R , R , R , R , R , R , R , R or R each independently represents hydrogen, and a Ci-C ₆ alkyl or C ₃ -C ₆ cycloalkyl group;

24 25

R and R each independently represents hydrogen, and a Ci-C ₆ alkyl or

C ₃ -C ₆ cycloalkyl group; or

24 25

R and R together with the nitrogen atom to which they are attached form a 3- to 8- membered saturated or partially saturated heterocyclic ring, optionally containing further heteroatoms or heterogroups selected from nitrogen, S(0) _m or oxygen;

9 12 15 23

R ₅ R , R and R represent Ci-Cg alkyl or C3-C6 cycloalkyl;

R and R are defined as for R and R respectively;

20 R represents a Ci-Cg alkyl optionally substituted by one or more substituents

23 independently selected from halogen, hydroxyl or OR ; m, p, q and r each independently represent an integer 0, 1 or 2; and

A represents a Cg-Cjo ^ar yl or C5-C12 heteroaryl group; or a pharmaceutically acceptable salt thereof.

In the context of the present specification, unless otherwise stated, an alkyl substituent group or an alkyl moiety in a substituent group may be linear or branched. Examples of C^ -Cg alkyl groups/moieties include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl and n-hexyl. Similarly, an alkylene group/moiety may be linear or branched.

Examples of Ci-Cg alkylene groups/moieties include methylene, ethylene, n-propylene, n- butylene, n-pentylene, n-hexylene, 1-methylethylene, 2-methylethylene, 1,2- dimethylethylene, 1-ethylethylene, 2-ethylethylene, 1-, 2- or 3-methylpropylene and 1-, 2- or

3-ethylpropylene. A Ci-Cg haloalkyl or Ci-Cg haloalkoxy substituent group/moiety will comprise at least one halogen atom, e.g. one, two, three, four or five halogen atoms, examples of which include trifluoromethyl, trifluoromethoxy or pentafluoroethyl. The alkyl groups in a di-Ci-Cg alkylamino group/moiety may be the same as, or different from, one another. A Ci- Cg hydroxyalkyl or Ci-Cg hydroxyalkoxy substituent group/moiety will comprise at least one hydroxyl group, e.g. one, two or three hydroxyl groups. An aryl or heteroaryl substituent group/moiety may be monocyclic or polycyclic (e.g. bicyclic or tricyclic) in which the two or more rings are fused. A heteroaryl group/moiety will comprise at least one ring heteroatom (e.g. one, two, three or four ring heteroatoms independently) selected from nitrogen, oxygen and sulphur. Examples of aryl and heteroaryl groups/moieties include phenyl, 1-naphthyl, 2- naphthyl, furyl, thienyl, pyrrolyl, pyridyl, indolyl, isoindolyl, quinolyl, isoquinolyl, pyrazolyl, imidazolyl, pyrimidinyl, pyrazinyl, pyridazinyl, thiazolyl and oxazolyl. A heterocyclic ring is defined as a saturated or partially saturated 3-8 membered ring containing at least one hetero

atom or group selected from nitrogen, sulphur, SO, SO2 or oxygen. The ring may be fused with a Cg-Cio aryl or C5-C12 heteroaryl group. Examples include morpholine, azetidine, pyrrolidine, piperidine, piperazine, 3-pyrroline, isoindoline, tetrahydroquinoline and thiomoφholine.

A C2-C10 acyloxy group/moiety is exemplified by a C2-C5 alkylcarbonyloxy group, a C2-C5 alkenylcarbonyloxy group, a C2-C5 alkynylcarbonyloxy group, a C6-C9 arylcarbonyloxy group or a C5-C9 heteroarylcarbonyloxy group, each of which may be optionally substituted by one or more substituents independently selected from halogen, hydroxyl, C1-C3 alkoxy or phenyl providing that the total number of carbon atoms in the acyloxy group does not exceed 10.

Preferably X represents oxygen.

Preferably Y represents Cj-Cg alkylene and R represents hydrogen

Preferably Z represents C2-Cg alkylene, more preferably (CH ₂ ) ₃ .

2 Preferably Y represents C]-Cg alkylene, more preferably a CH ₂ group.

Preferably A represents a Cg-C 10 aryl, more preferably phenyl.

Preferably Y represents Ci-Cg alkylene, more preferably CH ₂ .

2 Preferably R represents Ci-Cg alkyl more preferably methyl.

Preferably R represents SO2R ⁵ or COR ⁵ .

Examples of compounds of the invention include:

Methyl [4-({[3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H ^r -purm-9-yl)propyl][(4- methylpiperazin-l-yl)acetyl]amino}methyl)phenyl]acetate, Methyl (4-{[[3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H-purin-9-yl)pr oρyl](N,N- dimethylglycyl)amino]methyl}phenyl)acetate,

Methyl [4-( { [3 -(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H-purin-9-yl)propyl] [(I - methylpiperidin-4-yl)carbonyl]amino}methyl)phenyl]acetate,

Methyl [4-({[3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H-purin-9-yl)pr opyl][4- (dimethylamino)butanoyl]amino}methyl)phenyl]acetate,

Methyl (4-{[[3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H-purin-9-yl)pr oρyl](N _; ^V-dimethyl- β-alanyl)amino]methyl}phenyl)acetate,

Methyl [4-({[3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H-ρurin-9-yl)p ropyl][N^V-bis(2- hydroxyethyl)glycyl]amino}methyl)phenyl]acetate, Methyl {4-[([3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H-ρurin-9-yl)p roρyl] {[4-(2- hydroxyethyl)piperazin- 1 -yl] acetyl} amino)methyl]phenyl} acetate,

Methyl {4-[([3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H-purin-9-yl)pr opyl]{[4-

(methylsulfonyl)piperazin- 1 -yl]acetyl} amino)methyl]phenyl} acetate,

Methyl [3-({[3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H-purin-9-yl)pr oρyl][(l- methylpiperidin-4-yl)carbonyl]amino}methyl)phenyl]acetate,

Methyl [3-({[3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H-purin-9-yl)pr oρyl][(l- methylpiperidin-4-yl)carbonyl]amino}methyl)phenyl]acetate,

Methyl (3- {[[3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H-purin-9- yl)propyl](glycyl)amino]methyl}phenyl)acetate, Methyl [3-({[3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H-purin-9- yl)propyl][(methylthio)acetyl]amino}methyl)phenyl]acetate,

Methyl [3-({[3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H-purin-9- yl)propyl][(methylsulfinyl)acetyl]amino}methyl)phenyl]acetat e,

Methyl [3-({[3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H-purin-9- yl)propyl][(methylsulfonyl)acetyl]amino}methyl)phenyl]acetat e,

Methyl [3-({[3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H ^" -purin-9-yl)propyl][3-

(methylthio)propanoyl] amino } methyl)phenyl] acetate,

Methyl [3-({[3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H-purin-9-yl)pr opyl][3-

(methylsulfonyl)propanoyl]amino}methyl)phenyl]acetate,

Methyl [3-({[3-(6-ammo-2-butoxy-8-oxo-7 ₅ 8-dihydro-9H-purin-9-yl)propyl][N-

(methylsulfonyl)glycyl]amino}methyl)phenyl]acetate, tert-Butyl 4- {[3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H-ρurin-9-yl)propy l][3-(2-methoxy-

2-oxoethyl)benzyl] amino } -4-oxobutanoate,

4-{[3-(6-Amino-2-butoxy-8-oxo-7,8-dihydro-9H-purin-9-yl)� �ropyl][3-(2-methoxy-2- oxoethyl)ben2yl]amino} -4-oxobutanoic acid,

Methyl 3-{[3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H-purin-9-yl)prop yl][3-(2-methoxy-2- oxoethyl)benzyl]amino}-3-oxopropanoate,

Methyl [3-({acetyl[3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H-purin-9 - yl)propyl]amino}methyl)phenyl]acetate,

Methyl (3- {[[3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H-ρurin-9- yl)propyl](methylsulfonyl)amino]methyl}phenyl)acetate, (4-{[[3-(6-Amino-2-butoxy-8-oxo-7,8-dihydro-purin-9-yl)[2R]- propyl]-(pyrrolidine-2- carbonyl)-amino]-methyl}-phenyl)-acetic acid methyl ester,

(4- { [[3-(6-Amino-2-butoxy-8-oxo-7,8-dihydro-ρurin-9-yl)-ρropyl ] [2S,4R](4-hydroxy- pyrrolidine^-carbony^-aminoj-methylj-pheny^-acetic acid methyl ester,

(4-{[[3-(6-Amino-2-butoxy-8-oxo-7,8-dihydro-purin-9-yl)-� �ropyl][2S]-(l-methyl- pyrrolidine-2-carbonyl)-amino]-methyl}-phenyl)-acetic acid methyl ester,

(4-{[[3-(6-Amino-2-butoxy-8-oxo-7,8-dihydro-purin-9-yl)-p ropyl]-(3-piperazin-l-yl- propionyl)-amino]-methyl}-phenyl)-acetic acid methyl ester,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7η-ρurin-9-yl)propyl-[2-[ 4-[3-(l- piperidyl)propyl]piperazin-l-yl]acetyl]amino]methyl]phenyl]a cetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-[3- (diethylcarbamoyl)-l- piperidyl]acetyl]amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-(4- phenyl-l- piperidyl)acetyl]amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-[4- (2-oxo-2-pyrrolidin-l- y l-ethyl)piperazin- 1 -yl] acetyl] amino]methyl]phenyl] acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-(l- piperidyl)acetyl]amino]methyl]phenyl]acetate,

Ethyl 4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)proρyl-[[4-

(methoxycarbonylmethy^phenyljmethyljcarbamoyymethyypipera zine-l-carboxylate,

2- [[3 -(6-Amino-2-butoxy- 8-oxo-7H-purin-9-yl)propyl- [[4- (methoxycarbonylmethyl)phenyl]methyl]carbamoyl]methyl-(2-cya noethyl)amino]acetic acid,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-(be n2yl-(2- dimethylaminoethyl)amino)acetyl]amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-(4- carbamoyl-l- piperidyl)acetyl]amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)ρropyl-[2-[( 3R)-3- hydroxypyrrolidin- 1 -yl] acetyl] amino]methyl]phenyl] acetate, tert-Butyl (2S)-l-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[[4- (methoxycarbonylmethy^phenyymethy^carbamoy^methyljpyrrolidin e^-carboxylate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-(2- cyanoethyl-(oxolan-2- ylmethyl)amino)acetyl]amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-(et hyl-(pyridin-4- ylmethyl)amino)acetyl]amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-(4- ethylpiperazin-l- yl)acetyl]amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-ρurin-9-yl)propyl-[2-(m ethyl-(2-pyridin-4- ylethyl)amino)acetyl]amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-(4- pyrrolidin-l-yl-l- piperidyl)acetyl]amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)ρropyl-[2-[( 2S)-2- carbamoylpyrrolidin- 1 -yl] acetyl] amino]methyl]phenyl] acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-(3, 6-dihydro-2H-pyridin- l-yl)acetyl]amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-ρurin-9-yl)proρyl-[2-( ethyl-(2- hydroxyethyl)amino)acetyl]amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)ρropyl-[2-(c yclohexyl-(2- hydroxyethyl)amino)acetyl]amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-[4- (hydroxymethyl)-l- piperidy 1] acetyl] amino]methyl]phenyl] acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-[4- (2- aminoethyl)piperazin-l-yl]acetyl]amino]methyl]phenyl]acetate ,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-[4- (2-hydroxyethyl)-l- piperidyl] acetyl] amino]methyl]phenyl] acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-[me thyl-(l-methyl-4- piperidyl)amino]acetyl]amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-(4- ben2yl-4-hydroxy- 1 - piperidyl)acetyl]amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-(4- cinnamylpiperazin-l- yl)acetyl]amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-ρurin-9-yl)ρropyl-[2-[ 4-[2-(2- hydroxyethoxy)ethyl]piperazin-l-yl]acetyl]amino]methyl]pheny l]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-(3- dimethylaminopropyl- methyl-amino)acetyl]amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-ρurin-9-yl)ρropyl-[2- (dimethylcarbamoylmethyl-methyl-amino)acetyl]amino]methyl]ph enyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)ρropyl-[2-[( 2R)-2- carbamoylpyrrolidin- 1 -y 1] acetyl] amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-ρurin-9-yl)propyl-[2-[( 2S,6R)-2,6- dimethylmorpholin-4-yl]acetyl]aniino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-(4- methyl-l,4-diazepan- 1 -yl)acetyl] amino]niethy l]phenyl] acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-puxin-9-yl)ρropyl-(2-mo rpholin-4- ylacetyl)amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-ρurin-9-yl)ρropyl-[2-[ 4-(3- hydroxyphenyl)piperazin- 1 -yl]acetyl]amino]methyl]phenyl]acetate,

Methyl 2-[4-[[[2-[3-(acetyl-methyl-amino)pyrrolidin-l-yl]acetyl]-[3 -(6-amino-2-butoxy-8- oxo-7H-purin-9-yl)propyl]amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-ρurin-9-yl)ρropyl-[2-[ (3S)-3- dimethylaminopyrrolidin- 1 -yl]acetyl]amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-(4- pyridin-4-ylpiperazin- 1 -yl)acetyl] amino]methyl]phenyl] acetate

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-ρurin-9-yl)propyl-[2-[4 -(3- dimethylaminopropyl)piperazin-l-yl]acetyl]amino]methyl]pheny l]acetate,

Methyl 2- [4- [ [3 -(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl- [2-(4-propan-2-ylpiperazin- l-yl)acetyl]amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-[4- (dimethylcarbamoylmethy^piperazin-l-y^acety^aminojmethy^phen yljacetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-[(2 -hydroxy-2-phenyl- ethyl)-methyl-amino]acetyl]amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-[4- (aminomethyl)-l- piperidyl] acetyl] amino]methyl]phenyl] acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-(me thyl-(2- methylaminoethyl)amino)acetyl]amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-(2-thi omorpholin-4- ylacetyl)amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-(4- phenylpiperazin-l- yl)acetyl]amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-(l, 3-dihydroisoindol-2- yl)acetyl]amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-(2-pip erazin-l- ylacetyl)amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-[4- (l-piperidyl)-l- piperidyl] acetyl] amino]methyl]phenyl] acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-(4- pyridin-2-ylpiperazin- 1 -yl)acetyl] amino]methyl]phenyl] acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-(4- hydroxy-l- piperidyl)acetyl]amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-ρurin-9-yl)ρropyl-[2-[ 4-(4- fluorophenyl)piperazin-l-yl]acetyl]amino]methyl]phenyl]aceta te,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-(4- methyl-l- piperidyl)acetyl] amino]methyl]phenyl] acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-(2, 5-dihydropyrrol-l- yl)acetyl]amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-(4- benzothiazol-2- ylpiperazin-l-yl)acetyl]amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-ρurin-9-yl)propyl-[2-[4 - (ethoxycarbonylmethy^-l-piperidyllacetyljaminojmethy^pheny^a cetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-[4- (2- dimethylaminoethyl)piperazin- 1 -yl] acetyl] amino]methyl]phenyl] acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-ρurin-9-yl)ρropyl-[2-[ 4-(2- methylphenyl)piperazin-l-yl]acetyl]amino]methyl]phenyl]aceta te,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-(4- ethylsulfonylpiperazin- l-yl)acetyl]amino]methyl]phenyl]acetate,

(2S,4R)-l-[[3-(6-Amino-2-butoxy-8-oxo-7H-purin-9-yl)propy l-[[4- (methoxycarbonylmethyl)phenyl]methyl]carbamoyl]methyl]-4-hyd roxy-pyrrolidine-2- carboxylic acid,

(2S)-2-[[3-(6-Amino-2-butoxy-8-oxo-7H-ρurin-9-yl)proρyl -[[4- (methoxycarbonylmethyl)phenyl]methyl] carbamoyljmethyl-methyl-amino] -3 -phenyl- propanoic acid,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-[(2 S)-2- (hy droxymethyl)pyrrolidin- 1 -yl] acetyl] amino]methyl]phenyl] acetate,

3-[[3-(6-Amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[[4- (methoxycarbonylmethyl)phenyl]methyl]carbamoyl]methyl-(l , 1 -dioxothiolan-3- yl)amino]propanoic acid,

3-[[3-(6-Amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[[4-

(methoxycarbonylmethyl)phenyl]methyl]carbamoyl]methyl-cyc lohexyl-amino]propanoic acid,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-ρurin-9-yl)propyl-[2-(e thyl-(2- ethylaminoethyl)amino)acetyl]amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-(et hyl-(3- ethylaminopropyl)amino)acetyl]amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-(3, 4-dihydro-lH- isoquinolin-2-yl)acetyl]amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-ρurin-9-yl)ρropyl-[2-[ (2S)-2-(ρyrrolidin-l- ylmethyl)pyrrolidin- 1 -yl] acetyl] amino]methyl]phenyl] acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-[4- [(l-methyl-4- piperidyl)methyl]piperazin-l-yl]acetyl]amino]methyl]phenyl]a cetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-(me thyl-prop-2-ynyl- amino)acetyl]amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-[(l -methyl-4-piperidyl)- phenethyl-amino]acetyl]amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-[4- (oxolan-2- ylmethyl)piperazin- 1 -yl]acetyl]amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-[(3 R)-3-aminopyrrolidin- l-yl]acetyl]amino]methyl]phenyl]acetate,

tert-Butyl (2R)-l-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[[4- (methoxycarbonylmethy^phenyymethyljcarbamoyljmethyypyrrolidi ne^-carboxylate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-(4- pyrimidin-2- ylpiperazin-l-yl)acetyl]amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-(2-pyr rolidin-l- ylacetyl)amino]methyl]phenyl]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-p\jrin-9-yl)propyl-[2-[( 2S)-2-

(methoxymethyl)pyrrolidin-l-yl]acetyl]amino]methyl]phenyl ]acetate,

Methyl 2-[4-[[3-(6-amino-2-butoxy-8-oxo-7H-purin-9-yl)propyl-[2-[(2 R)-2- (methoxymethyl)pyrrolidin-l-yl]acetyl]amino]methyl]phenyl]ac etate,

and pharmaceutically acceptable salts thereof. c

The present invention further provides a process for the preparation of a compound of formula (I) or a pharmaceutically acceptable salt thereof as defined above which comprises,

4 5

(a) when R represents COR , reacting a compound of formula (II)

wherein n, A, Y ¹ , Y ² , Y ³ , X ¹ , Z ¹ , R, R and R are as defined in formula (I), with a compound of formula (III), wherein R is as defined in formula (I), using an appropriate coupling reagent (for example, N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide (EDC) or O-(7- azabenzotriazol-l-yl)-N,N,N',N'-tetramethyluronium hexafluorophosphate (HATU)), in the presence of a base such as diisopropyl ethylamine, triethylamine or pyridine in an organic

solvent (for example dimethylformamide, dichloromethane or acetonitrile) at a temperature in the range, for example, from 0 to 150°C [alternatively, the acid (III) may be activated by formation of an acid halide using a halogenating reagent such as oxalyl chloride or thionyl chloride; the acid chloride may then be reacted with a compound of formula (II) in the presense of a base such as diisopropyl ethylamine, triethylamine or pyridine in an organic solvent (for example dimethylformamide, dichloromethane or acetonitrile) at a temperature in the range, for example, from 0 to 150 ⁰ C];

4 5 5 13 14

(b) when R represents COR and R represents Ci-Cg alkyl substituted by NR R , reacting a compound of formula (IV)

wherein L ² represents a leaving group such as a halogen, mesylate or triflate, t is an integer from 1 to 6, and n, A, Y ¹ , Y ² , Y ³ , X ¹ , Z ¹ , R, R ¹ and R ² are as defined in formula (I), with a compound of formula

13

H-N 14

(V)

wherein R ¹³ and R ¹⁴ are as defined in formula (I) [the reaction may be carried out in the presense of a base (for example diisopropyl ethylamine, triethylamine or pyridine) in an organic solvent such as dimethylformamide, dimethylsulphoxide or acetonitrile at a temperature, for example, in the range from 0 to 15O ⁰ C];

4 5

(c) when R represents a group SO2R , reacting a compound of formula (II) as defined in (a)

3 5 3 above with a compound of formula (VI), L -S(O)2~R , wherein L represents a leaving group (e.g. halogen) and R is as defined in formula (I), in the presence of a base;

4 5

(d) when R represents a group CO2R , reacting a compound of formula (II) as defined in (a)

4 5 4 above with a compound of formula (VII), L -C(O)-OR , wherein L represents a leaving group (e.g. halogen) and R is as defined in formula (I), in the presence of a base;

4 6 7 (e) when R represents a group SO2NR R , reacting a compound of formula (II) as defined in (a) above with a compound of formula (VIII), L -S(O)2-NR R , wherein L represents a leaving group (e.g. halogen) and R and R are as defined in formula (I), in the presence of a base;

or

4 6 7

(f) when R represents a group CONR R , reacting a compound of formula (II) as defined in

(a) above with a compound of formula (IX), L -C(O)-NR R , wherein L represents a leaving group (e.g. halogen) and R and R are as defined in formula (I), in the presence of a base;

and optionally thereafter carrying out one or more of the following procedures:

• converting a compound of formula (I) into another compound of formula (I),

• removing any protecting groups, • forming a pharmaceutically acceptable salt.

In each of processes (c), (d), (e) and (f) above, the reaction is conveniently carried out in an organic solvent such as dimethylformamide, dichloromethane or acetonitrile at a temperature

in the range from 0°C to 150°C. Suitable bases include diisopropyl ethylamine, triethylamine and pyridine.

A compound of formula (IV) may be prepared by reacting a compound of formula (II) with a compound of formula (X)

wherein L ² and t are as defined in formula (IV). The reaction may be carried out using similar conditions to couple compounds of formulae (II) and (III).

A compound of formula (II) may be obtained by the treatment of a compound of formula (XI)

wherein n, A, Y ¹ , Y ² , Y ³ , X ¹ , Z ¹ , R, R and R are as defined in formula (I) with an acid. The reaction may be carried out in an organic solvent such as methanol, tetrahydrofuran or dioxane using either an inorganic acid such as hydrochloric acid, hydrobromic acid or sulfuric acid, or an organic acid such as trifluoroacetic acid.

A compound of formula (XI) may be obtained by the treatment of a compound of formula (XII)

wherein Z ¹ , X ¹ , Y ¹ and R are as defined in formula (I) with a compound of formula (XIII), wherein Y ⁴ represents a bond or a C1-C5 alkylene group and n, A, Y ³ , R and R are as defined in formula (I). The reaction may be carried out in the presense of a suitable reducing agent (for example sodium triacetoxyborohydride or sodium borohydride), in an organic solvent such as l-methyl-2-pyrrolidinone, 1,2-dichloroethane, tetrahydrofuran or methanol at a temperature, for example, in the range from 0 to 150°C.

A compound of formula (XII) above may be obtained by treatment of a compound of formula

wherein Z ¹ , X ¹ , Y ¹ and R are as defined in formula (I) and PG ₁ represents a protecting group, e.g. phthalimide or Fmoc, which may be deprotected using hydrazine in ethanol or an organic base such as piperidine.

A compound of formula (XIV) may be prepared by reacting a compound of formula (XV)

(XV)

wherein X ¹ , Y ¹ and R are as defined in formula (I), with a compound of formula (XVI) ₅ wherein L ⁷ represents a leaving group such as a halogen, mesylate or triflate, and Z ¹ is as defined in formula (I) and PG ₁ is as defined above. The reaction may conveniently be carried out in an organic solvent such as dimethylformamide, dimethylsulphoxide or acetonitrile in the presense of a base such as an alkali metal carbonate (for example sodium carbonate or potassium carbonate) or an alkaline earth metal carbonate (for example calcium carbonate), a metal hydroxide (for example sodium hydroxide or potassium hydroxide) at a temperature, for example, in the range from 0 to 150 ⁰ C, preferably at room temperature (2O ⁰ C).

The protection and deprotection of functional groups is described in 'Protective Groups in Organic Chemistry', edited by J.W.F. McOmie, Plenum Press (1973) and 'Protective Groups in Organic Synthesis', 3 ^rd edition, T.W. Greene and P.G.M. Wuts, Wiley-Interscience (1999).

The compounds defined in the formula (XV) may be obtained following the procedure described in the patent WO2005/092893.

Compounds of formulae (III), (V), (VI), (VII), (VIII), (IX), (X), (XI), (XIII) and (XVI) are either commercially available, are well known in the literature or may be prepared using known techniques.

The compounds of formula (I) above may be converted to a pharmaceutically acceptable salt thereof, preferably an acid addition salt such as a hydrochloride, hydrobromide, trifluoroacetate, sulphate, phosphate, acetate, fumarate, maleate, tartrate, lactate, citrate, pyruvate, succinate, oxalate, methanesulphonate or^»-toluenesulphonate.

Compounds of formula (I) is capable of existing in stereoisomeric forms. It will be understood that the invention encompasses the use of all geometric and optical isomers (including atropisomers) of the compounds of formula (I) and mixtures thereof including racemates. The use of tautomers and mixtures thereof also form an aspect of the present invention. Enantiomerically pure forms are particularly desired.

The compounds of formula (I) and their pharmaceutically acceptable salts have activity as pharmaceuticals, in particular as modulators of toll-like receptor (especially TLR7) activity, and thus may be used in the treatment of: 1. respiratory tract: obstructive diseases of the airways including: asthma, including bronchial, allergic, intrinsic, extrinsic, exercise-induced, drug-induced (including aspirin and NSAID-induced) and dust-induced asthma, both intermittent and persistent and of all severities, and other causes of airway hyper-responsiveness; chronic obstructive pulmonary disease (COPD); bronchitis, including infectious and eosinophilic bronchitis; emphysema; bronchiectasis; cystic fibrosis; sarcoidosis; farmer's lung and related diseases; hypersensitivity pneumonitis; lung fibrosis, including cryptogenic fibrosing alveolitis, idiopathic interstitial pneumonias, fibrosis complicating anti-neoplastic therapy and chronic infection, including tuberculosis and aspergillosis and other fungal infections; complications of lung transplantation; vasculitic and thrombotic disorders of the lung vasculature, and pulmonary hypertension; antitussive activity including treatment of chronic cough associated with inflammatory and secretory conditions of the airways, and iatrogenic cough; acute and chronic rhinitis including rhinitis medicamentosa, and vasomotor rhinitis; perennial and seasonal allergic rhinitis including rhinitis nervosa (hay fever); nasal polyposis; acute viral infection including the common cold, and infection due to respiratory syncytial virus, influenza, coronavirus (including SARS) and adenovirus;

2. skin: psoriasis, atopic dermatitis, contact dermatitis or other eczematous dermatoses, and delayed-type hypersensitivity reactions; phyto- and photodermatitis; seborrhoeic dermatitis, dermatitis herpetiformis, lichen planus, lichen sclerosus et atrophica, pyoderma gangrenosum, skin sarcoid, discoid lupus erythematosus, pemphigus, pemphigoid, epidermolysis bullosa, urticaria, angioedema, vasculitides, toxic erythemas, cutaneous eosinophilias, alopecia areata, male-pattern baldness, Sweet's syndrome, Weber-Christian syndrome, erythema multiforme; cellulitis, both infective and non-infective; panniculitis;cutaneous lymphomas, non-melanoma skin cancer and other dysplastic lesions; drug-induced disorders including fixed drug eruptions; 3. eyes: blepharitis; conjunctivitis, including perennial and vernal allergic conjunctivitis; iritis; anterior and posterior uveitis; choroiditis; autoimmune, degenerative or inflammatory

disorders affecting the retina; ophthalmitis including sympathetic ophthalmitis; sarcoidosis; infections including viral , fungal, and bacterial;

4. genitourinary: nephritis including interstitial and glomerulonephritis; nephrotic syndrome; cystitis including acute and chronic (interstitial) cystitis and Hunner's ulcer; acute and chronic urethritis, prostatitis, epididymitis, oophoritis and salpingitis; vulvo-vaginitis; Peyronie's disease; erectile dysfunction (both male and female);

5. allograft rejection: acute and chronic following, for example, transplantation of kidney, heart, liver, lung, bone marrow, skin or cornea or following blood transfusion; or chronic graft versus host disease; 6. other auto-immune and allergic disorders including rheumatoid arthritis, irritable bowel syndrome, systemic lupus erythematosus, multiple sclerosis, Hashimoto's thyroiditis, Graves' disease, Addison's disease, diabetes mellitus, idiopathic thrombocytopaenic purpura, eosinophilic fasciitis, hyper-IgE syndrome, antiphospholipid syndrome and Sazary syndrome;

7. oncology: treatment of common cancers including prostate, breast, lung, ovarian, pancreatic, bowel and colon, stomach, skin and brain tumors and malignancies affecting the bone marrow (including the leukaemias) and lymphoproliferative systems, such as Hodgkin's and non-Hodgkin's lymphoma; including the prevention and treatment of metastatic disease and tumour recurrences, and paraneoplastic syndromes; and,

8. infectious diseases: virus diseases such as genital warts, common warts, plantar warts, respiratory syncytial virus (RSV), hepatitis B, hepatitis C, herpes simplex virus, molluscum contagiosum, variola, human immunodeficiency virus (HIV), human papilloma virus (HPV), cytomegalovirus (CMV), varicella zoster virus (VZV), rhinovirus, adenovirus, coronavirus, influenza, para-influenza; bacterial diseases such as tuberculosis and mycobacterium avium, leprosy; other infectious diseases, such as fungal diseases, chlamydia, Candida, aspergillus, cryptococcal meningitis, Pneumocystis carnii, cryptosporidiosis, histoplasmosis, toxoplasmosis, trypanosome infection and leishmaniasis.

Thus, the present invention provides a compound of formula (I) or a pharmaceutically- acceptable salt thereof as hereinbefore defined for use in therapy.

In a further aspect, the present invention provides the use of a compound of formula (I) or a pharmaceutically acceptable salt thereof as hereinbefore defined in the manufacture of a medicament for use in therapy.

In the context of the present specification, the term "therapy" also includes "prophylaxis" unless there are specific indications to the contrary. The terms "therapeutic" and "therapeutically" should be construed accordingly.

Prophylaxis is expected to be particularly relevant to the treatment of persons who have suffered a previous episode of, or are otherwise considered to be at increased risk of, the disease or condition in question. Persons at risk of developing a particular disease or condition generally include those having a family history of the disease or condition, or those who have been identified by genetic testing or screening to be particularly susceptible to developing the disease or condition.

In particular, the compounds of the invention may be used in the treatment of asthma, COPD, allergic rhinitis, allergic conjunctivitis, atopic dermatitis, cancer, hepatitis B, hepatitis C, HIV, HPV, respiratory syncytial virus (RSV), bacterial infections and dermatosis.

The invention still further provides a method of treating, or reducing the risk of, an obstructive airways disease or condition (e.g. asthma or COPD) which comprises administering to a patient in need thereof a therapeutically effective amount of a compound of formula (I) or a pharmaceutically acceptable salt thereof as hereinbefore defined.

For the above-mentioned therapeutic uses the dosage administered will, of course, vary with the compound employed, the mode of administration, the treatment desired and the disorder indicated. For example, the daily dosage of the compound of the invention, if inhaled, may be in the range from 0.05 micrograms per kilogram body weight (μg/kg) to 100 micrograms per kilogram body weight (μg/kg). Alternatively, if the compound is administered orally, then the daily dosage of the compound of the invention may be in the range from 0.01 micrograms per kilogram body weight (μg/kg) to 100 milligrams per kilogram body weight (mg/kg).

The compounds of formula (I) and pharmaceutically acceptable salts thereof may be used on their own but will generally be administered in the form of a pharmaceutical composition in which the formula (I) compound/salt (active ingredient) is in association with a pharmaceutically acceptable adjuvant, diluent or carrier. Conventional procedures for the selection and preparation of suitable pharmaceutical formulations are described in, for example, "Pharmaceuticals - The Science of Dosage Form Designs", M. E. Aulton, Churchill Livingstone, 1988.

Depending on the mode of administration, the pharmaceutical composition will preferably comprise from 0.05 to 99 %w (per cent by weight), more preferably from 0.05 to 80 %w, still more preferably from 0.10 to 70 %w, and even more preferably from 0.10 to 50 %w, of active ingredient, all percentages by weight being based on total composition.

The present invention also provides a pharmaceutical composition comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof as hereinbefore defined, in association with a pharmaceutically acceptable adjuvant, diluent or carrier.

The invention further provides a process for the preparation of a pharmaceutical composition of the invention which comprises mixing a compound of formula (I) or a pharmaceutically acceptable salt thereof as hereinbefore defined with a pharmaceutically acceptable adjuvant, diluent or carrier.

The pharmaceutical compositions may be administered topically (e.g. to the skin or to the lung and/or airways) in the form, e.g., of creams, solutions, suspensions, heptafluoroalkane (PIF A) aerosols and dry powder formulations, for example, formulations in the inhaler device known as the Turbuhaler ^® ; or systemically, e.g. by oral administration in the form of tablets, capsules, syrups, powders or granules; or by parenteral administration in the form of solutions or suspensions; or by subcutaneous administration; or by rectal administration in the form of suppositories; or transdermally.

Dry powder formulations and pressurized HFA aerosols of the compounds of the invention (including pharmaceutically acceptable salts) may be administered by oral or nasal inhalation.

For inhalation, the compound is desirably finely divided. The finely divided compound preferably has a mass median diameter of less than 10 micrometres (μm), and may be suspended in a propellant mixture with the assistance of a dispersant, such as a C§-C20 fatty acid or salt thereof, (for example, oleic acid), a bile salt, a phospholipid, an alkyl saccharide, a perfluorinated or polyethoxylated surfactant, or other pharmaceutically acceptable dispersant.

The compounds of the invention may also be administered by means of a dry powder inhaler. The inhaler may be a single or a multi dose inhaler, and may be a breath actuated dry powder inhaler.

One possibility is to mix the finely divided compound of the invention with a carrier substance, for example, a mono-, di- or polysaccharide, a sugar alcohol, or another polyol. Suitable carriers are sugars, for example, lactose, glucose, raffinose, melezitose, lactitol, maltitol, trehalose, sucrose, mannitol; and starch. Alternatively the finely divided compound may be coated by another substance. The powder mixture may also be dispensed into hard gelatine capsules, each containing the desired dose of the active compound.

Another possibility is to process the finely divided powder into spheres which break up during the inhalation procedure. This spheronized powder may be filled into the drug reservoir of a multidose inhaler, for example, that known as the Turbuhaler ^® in which a dosing unit meters the desired dose which is then inhaled by the patient. With this system the active ingredient, with or without a carrier substance, is delivered to the patient.

For oral administration the compound of the invention may be admixed with an adjuvant or a carrier, for example, lactose, saccharose, sorbitol, mannitol; a starch, for example, potato starch, corn starch or amylopectin; a cellulose derivative; a binder, for example, gelatine or polyvinylpyrrolidone; and/or a lubricant, for example, magnesium stearate, calcium stearate, polyethylene glycol, a wax, paraffin, and the like, and then compressed into tablets. If coated tablets are required, the cores, prepared as described above, may be coated with a concentrated sugar solution which may contain, for example, gum arabic, gelatine, talcum and

titanium dioxide. Alternatively, the tablet may be coated with a suitable polymer dissolved in a readily volatile organic solvent.

For the preparation of soft gelatine capsules, the compound of the invention may be admixed with, for example, a vegetable oil or polyethylene glycol. Hard gelatine capsules may contain granules of the compound using either the above-mentioned excipients for tablets. Also liquid or semisolid formulations of the compound of the invention may be filled into hard gelatine capsules.

Liquid preparations for oral application may be in the form of syrups or suspensions, for example, solutions containing the compound of the invention, the balance being sugar and a mixture of ethanol, water, glycerol and propylene glycol. Optionally such liquid preparations may contain colouring agents, flavouring agents, saccharine and/or carboxymethylcellulose as a thickening agent or other excipients known to those skilled in art.

The compounds of the invention may also be administered in conjunction with other compounds used for the treatment of the above conditions.

The invention therefore further relates to combination therapies wherein a compound of the invention or a pharmaceutical composition or formulation comprising a compound of the invention is administered concurrently or sequentially or as a combined preparation with another therapeutic agent or agents, for the treatment of one or more of the conditions listed.

In particular, for the treatment of the inflammatory diseases COPD, asthma and allergic rhinitis the compounds of the invention may be combined with agents such as tumour necrosis factor alpha (TNF-alpha) inhibitors such as anti-TNF monoclonal antibodies (for example Remicade, CDP-870 and adalimumab) and TNF receptor immunoglobulin molecules (such as Enbrel); non-selective cyclo-oxygenase COX-l/COX-2 inhibitors whether applied topically or systemically (such as piroxicam, diclofenac, propionic acids such as naproxen, flubiprofen, fenoprofen, ketoprofen and ibuprofen, fenamates such as mefenamic acid, indomethacin, sulindac, azapropazone, pyrazolones such as phenylbutazone, salicylates such as aspirin), COX-2 inhibitors (such as meloxicam, celecoxib, rofecoxib, valdecoxib, lumarocoxib,

parecoxib and etoricoxib); glucocorticosteroids (whether administered by topical,oral, intramuscular, intravenous, or intra-articular routes); methotrexate, lefunomide; hydroxychloroquine, d-penicillamine, auranofin or other parenteral or oral gold preparations.

The present invention still further relates to the combination of a compound of the invention and a leukotriene biosynthesis inhibitor, 5-lipoxygenase (5-LO) inhibitor or 5-lipoxygenase activating protein (FLAP) antagonist such as; zileuton; ABT-761; fenleuton; tepoxalin; Abbott-79175; Abbott-85761; a N-(5-substituted)-thiophene-2-alkylsulfonamide; 2,6-di-tert- butylphenolhydrazones; a methoxytetrahydropyrans such as Zeneca ZD-2138; the compound SB-210661; a pyridinyl-substituted 2-cyanonaphthalene compound such as L-739,010; a 2- cyanoquinoline compound such as L-746,530; or an indole or quinoline compound such as MK-591, MK-886, and BAY x 1005.

The present invention further relates to the combination of a compound of the invention and a receptor antagonist for leukotrienes (LT B4, LTC4, LTD4, and LTE4) selected from the group consisting of the phenothiazin-3-ls such as L-651,392; amidino compounds such as CGS-25019c; benzoxalamines such as ontazolast; benzenecarboximidamides such as BIIL 284/260; and compounds such as zafirlukast, ablukast, montelukast, pranlukast, verlukast (MK-679), RG-12525, Ro-245913, iralukast (CGP 45715A), and BAY x 7195.

The present invention still further relates to the combination of a compound of the invention and a phosphodiesterase (PDE) inhibitor such as a methylxanthanine including theophylline and aminophylline; a selective PDE isoenzyme inhibitor including a PDE4 inhibitor an inhibitor of the isoform PDE4D, or an inhibitor of PDE5.

The present invention further relates to the combination of a compound of the invention and a histamine type 1 receptor antagonist such as cetirizine, loratadine, desloratadine, fexofenadine, acrivastine, terfenadine, astemizole, azelastine, levocabastine, chlorpheniramine, promethazine, cyclizine, or mizolastine; applied orally, topically or parenterally.

The present invention still further relates to the combination of a compound of the invention and a gastroprotective histamine type 2 receptor antagonist.

The present invention further relates to the combination of a compound of the invention and an antagonist of the histamine type 4 receptor.

The present invention still further relates to the combination of a compound of the invention and an alpha- l/alpha-2 adrenoceptor agonist vasoconstrictor sympathomimetic agent, such as propylhexedrine, phenylephrine, phenylpropanolamine, ephedrine, pseudoephedrine, naphazoline hydrochloride, oxymetazoline hydrochloride, tetrahydrozoline hydrochloride, xylometazoline hydrochloride, tramazoline hydrochloride or ethylnorepinephrine hydrochloride.

The present invention further relates to the combination of a compound of the invention and an anticholinergic agent including muscarinic receptor (Ml, M2, and M3) antagonists such as atropine, hyoscine, glycopyrrrolate, ipratropium bromide, tiotropium bromide, oxitropium bromide, pirenzepine or telenzepine.

The present invention still further relates to the combination of a compound of the invention together with a beta-adrenoceptor agonist (including beta receptor subtypes 1-4) such as isoprenaline, salbutamol, formoterol, salmeterol, terbutaline, orciprenaline, bitolterol mesylate, and pirbuterol.

The present invention further relates to the combination of a compound of the invention and a chromone, such as sodium cromoglycate or nedocromil sodium.

The present invention still further relates to the combination of a compound of the invention together with an insulin-like growth factor type I (IGF-I) mimetic.

The present invention still further relates to the combination of a compound of the invention and a glucocorticoid, such as flunisolide, triamcinolone acetonide, beclomethasone dipropionate, budesonide, fluticasone propionate, ciclesonide or mometasone furoate.

The present invention still further relates to the combination of a compound of the invention together with an inhibitor of matrix metalloproteases (MMPs), i.e., the stromelysins, the collagenases, and the gelatinases, as well as aggrecanase; especially collagenase-1 (MMP-I), collagenase-2 (MMP-8), collagenase-3 (MMP-13), stromelysin-1 (MMP-3), stromelysin-2 (MMP-IO), and stromelysin-3 (MMP-Il) andMMP-9 and MMP-12.

The present invention still further relates to the combination of a compound of the invention together with modulators of chemokine receptor function such as antagonists of CCRl, CCR2, CCR2A, CCR2B, CCR3, CCR4, CCR5, CCR6, CCR7, CCR8, CCR9, CCRlO and CCRl 1 (for the C-C family); CXCRl, CXCR2, CXCR3, CXCR4 and CXCR5 (for the C-X-C family) and CX3CR1 for the C-X3-C family.

The present invention still further relates to the combination of a compound of the invention together with a cytokine or modulator of cytokine function, including alpha-, beta-, and gamma-interferon; interleukins (IL) including ILl to 15, and interleukin antagonists or inhibitors, including agents which act on cytokine signalling pathways.

The present invention still further relates to the combination of a compound of the invention together with an immunoglobulin (Ig) or Ig preparation or an antagonist or antibody modulating Ig function such as anti-IgE (omalizumab).

The present invention further relates to the combination of a compound of the invention and another systemic or topically-applied anti-inflammatory agent, such as thalidomide or a derivative thereof, a retinoid, dithranol or calcipotriol.

The present invention further relates to the combination of a compound of the invention together with an antibacterial agent such as a penicillin derivative, a tetracycline, a macrolide, a beta-lactam, a fluoroquinolone, metronidazole, an inhaled aminoglycoside; an antiviral agent including acyclovir, famciclovir, valaciclovir, ganciclovir, cidofovir, amantadine, rimantadine, ribavirin, zanamavir and oseltamavir; a protease inhibitor such as indinavir, nelfϊnavir, ritonavir, and saquinavir; a nucleoside reverse transcriptase inhibitor such as

didanosine, lamivudine, stavudine, zalcitabine or zidovudine; or a non-nucleoside reverse transcriptase inhibitor such as nevirapine or efavirenz.

The anti-cancer treatment defined hereinbefore may be applied as a sole therapy or may

5 involve, in addition to the compound of the invention, conventional surgery or radiotherapy or chemotherapy. Such chemotherapy may include one or more of the following categories of anti-tumour agents:-

(i) an antiproliferative/antineoplastic drugs and combinations thereof, as used in medical oncology, such as alkylating agents (for example cis-platin, oxaliplatin, carboplatin, io cyclophosphamide, nitrogen mustard, melphalan, chlorambucil, busulphan, temozolamide and nitrosoureas); antimetabolites (for example gemcitabine and antifolates such as fluoropyrimidines like 5-fluorouracil and tegafur, raltitrexed, methotrexate, cytosine arabinoside, and hydroxyurea); antitumour antibiotics (for example anthracyclines like adriamycin, bleomycin, doxorubicin, daunomycin, epirubicin, idarubicin, mitomycin-C, is dactinomycin and mithramycin); antimitotic agents (for example vinca alkaloids like vincristine, vinblastine, vindesine and vinorelbine and taxoids like taxol and taxotere and polokinase inhibitors); and topoisomerase inhibitors (for example epipodophyllotoxins like etoposide and teniposide, amsacrine, topotecan and camptothecin); (ii) cytostatic agents such as antioestrogens (for example tamoxifen, fulvestrant, toremifene,

20 raloxifene, droloxifene and iodoxyfene), antiandrogens (for example bicalutamide, flutamide, nilutamide and cyproterone acetate), LHRH antagonists or LHRH agonists (for example goserelin, leuprorelin and buserelin), progestogens (for example megestrol acetate), aromatase inhibitors (for example as anastrozole, letrozole, vorazole and exemestane) and inhibitors of 5α-reductase such as finasteride;

2 ₅ (iii) anti-invasion agents (for example c-Src kinase family inhibitors like 4-(6-chloro-2,3- methylenedioxyanilino)-7-[2-(4-methylpiperazin-l-yl)ethoxy]- 5-tetrahydropyran-4- yloxyquinazoline (AZD0530; International Patent Application WO 01/94341) andiV-(2- chloro-6-methylphenyl)-2-{6-[4-(2-hydroxyethyl)piperazin-l-y l]-2-methylpyrimidin-4- ylamino}thiazole-5-carboxamide (dasatinib, BMS-354825; J. Med. Cherou 2004, 47, 6658-

30 6661), and metalloproteinase inhibitors like marimastat, inhibitors of urokinase plasminogen activator receptor function or antibodies to Heparanase);

(iv) inhibitors of growth factor function: for example such inhibitors include growth factor antibodies and growth factor receptor antibodies (for example the anti-erbB2 antibody trastuzumab [Herceptin™], the anti-EGFR antibody panitumumab, the anti-erbBl antibody cetuximab [Erbitux, C225] and any growth factor or growth factor receptor antibodies disclosed by Stern et al. Critical reviews in oncology/haematology, 2005, Vol. 54, ppl 1-29); such inhibitors also include tyrosine kinase inhibitors, for example inhibitors of the epidermal growth factor family (for example EGFR family tyrosine kinase inhibitors such as N-(3-chloro-4-fluorophenyl)-7-methoxy-6-(3-morpholinopropoxy )quinazolin-4-amine (gefitinib, ZDl 839), N-(3-ethynylphenyl)-6,7-bis(2-methoxyethoxy)quinazolin-4-ami ne (erlotinib, OSI-774) and 6-acrylamido-N-(3-chloro-4-fluorophenyl)-7-(3- morpholinopropoxy)-quinazolin-4-amine (CI 1033), erbB2 tyrosine kinase inhibitors such as lapatinib, inhibitors of the hepatocyte growth factor family, inhibitors of the platelet-derived growth factor family such as imatinib, inhibitors of serine/threonine kinases (for example Ras/Raf signalling inhibitors such as farnesyl transferase inhibitors, for example sorafenib (BAY 43-9006)), inhibitors of cell signalling through MEK and/or AKT kinases, inhibitors of the hepatocyte growth factor family, c-kit inhibitors, abl kinase inhibitors, IGF receptor (insulin-like growth factor) kinase inhibitors; aurora kinase inhibitors (for example AZDl 152, PH739358, VX-680, MLν8054, R763, MP235, MP529, VX-528 AND AX39459) and cyclin dependent kinase inhibitors such as CDK2 and/or CDK4 inhibitors; (v) antiangiogenic agents such as those which inhibit the effects of vascular endothelial growth factor, [for example the anti-vascular endothelial cell growth factor antibody bevacizumab (Avastin™) and VEGF receptor tyrosine kinase inhibitors such as 4-(4-bromo- 2-fluoroanilino)-6-methoxy-7-(l-methylpiperidin-4-ylmethoxy) quinazoline (ZD6474; Example 2 within WO 01/32651), 4-(4-fluoro-2-methylindol-5-yloxy)-6-methoxy-7-(3- pyrrolidin- 1 -ylpropoxy)quinazoline (AZD2171; Example 240 within WO 00/47212), vatalanib (PTK787; WO 98/35985) and SUl 1248 (sunitinib; WO 01/60814), compounds such as those disclosed in International Patent Applications WO97/22596, WO 97/30035, WO 97/32856 and WO 98/13354 and compounds that work by other mechanisms (for example linomide, inhibitors of integrin αvβ3 function and angiostatin)]; (vi) vascular damaging agents such as Combretastatin A4 and compounds disclosed in International Patent Applications WO 99/02166, WO 00/40529, WO 00/41669, WO 01/92224, WO 02/04434 and WO 02/08213;

(vii)antisense therapies, for example those which are directed to the targets listed above, such as ISIS 2503, an anti-ras antisense;

(viii) gene therapy approaches, including for example approaches to replace aberrant genes such as aberrant p53 or aberrant BRCAl or BRCA2, GDEPT (gene-directed enzyme pro-drug s therapy) approaches such as those using cytosine deaminase, thymidine kinase or a bacterial nitroreductase enzyme and approaches to increase patient tolerance to chemotherapy or radiotherapy such as multi-drug resistance gene therapy; and

(ix) immunotherapy approaches, including for example ex- vivo and in-vivo approaches to increase the immunogenicity of patient tumour cells, such as transfection with cytokines such o as interleukin 2, interleukin 4 or granulocyte-macrophage colony stimulating factor, approaches to decrease T-cell anergy, approaches using transfected immune cells such as cytokine-transfected dendritic cells, approaches using cytokine-transfected tumour cell lines and approaches using anti-idiotypic antibodies.

s The present invention will be further explained by reference to the following illustrative examples.

The following abbreviations are used;

0 EtOAc ethyl acetate

DCM dichloromethane

NMP N-methylpyrrolidine

NB S N-bromosuccinimide

DMF λζiV-dimethylformamide 5 DMSO dimethylsulfoxide

THF tetrahydrofuran

TFA trifluoroacetic acid

K ₂ CO ₃ potassium carbonate

NaHCO ₃ sodium hydrogen carbonate 0 MeCN acetonitrile mCPBA 3-chloroperoxybenzoic acid (Aldrich 77% max) rt room temperature

h hours min minutes

M molar

N normal

MS mass spectrometry

APCI atmospheric chemical ionisation method

ESI electron spray ionisation method

NMR nuclear magnetic resonance

HCl hydrochloric acid

BOC fertzαry-butoxycarbonyl

HOBt 1-hydroxybenzotriazole

EDC l-(3-dimethylamino propyl)-3-ethylcarbodiimide hydrochloride

HATU <9-(7-azabenzotriazol- 1 -yl)-N,N,N',N'-tetramethyluronium hexafluorophosphonate

Unless otherwise stated organic solutions were dried over magnesium sulphate. RPHPLC denotes Reversed Phase Preparative High Performance Liquid Chromatography using Waters Symmetry C8, Xterra or Phenomenex Gemini columns using acetonitrile and either aqueous ammonium acetate, ammonia, formic acid or trifluoroacetic acid as buffer where appropriate. Column chromatography was carried out on silica gel. SCX denotes solid phase extraction with a sulfonic acid sorbent whereby a mixture was absorbed on a sulfonic acid sorbent and eluted with an appropriate solvent such as methanol or acetonitrile and then the free base product was eluted with aqueous ammonia/an appropriate solvent such as methanol or acetonitrile.

Example 1

Methyl [4-({ [3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9Jϊ-purin-9-yl)propy l] [(4- methylpiperazin-l-yl)acetyl] amino} methyl)phenyl] acetate

(i) 2-Chloro-9-(tetrahydro-2H-pyran-2-yl)- 9H-purin-6-amine 2,6-Dichloro-9-(tetrahydxo-2H-pyran-2-yl)- 9H-purine (55g) was dissolved in 7N-aqueous ammonia in methanol (500ml) and heated at 100 ⁰ C in a sealed flask for 6h. The reaction mixture was cooled to rt and left overnight. Filtration afforded the subtitle compound. Yield

4Og.

¹ H NMR δ (CDCl ₃ ) 8.02 (IH, s), 5.94 (2H, brs), 5.71 (IH, dd), 4.15 - 4.22 (IH, m), 3.75 - 3.82 (IH, m), 1.27 - 2.12 (6H, m).

(ii) 2-Butoxy-9-(tetrahydro-2H-pyran-2-yl)-9H-purin-6-amine

The product from step (i) (4Og) was dissolved in 19%(w/w)-sodium butoxide in butanol (250ml). The reaction mixture was stirred under reflux for 6h. The resultant suspension was cooled to rt, diluted with water and extracted with diethyl ether. The combined organic phase was washed with water, dried and concentrated in vacuo. The subtitle compound was crystallized from diethyl ether/isohexane (1/1, 300ml) and obtained by filtration. Yield 19g. ¹ H NMR δ (CDCl ₃ ) 7.87 (IH, s), 5.56 - 5.68 (3H, m), 4.31 - 4.35 (2H, t), 4.14 - 4.17 (IH, m), 3.76 - 3.80 (IH, m), 1.49 - 2.08 (1OH, m), 0.98 (3H, t).

(iii) 8-Bromo-2-butoxy-9-(tetrahydro-2H-pyran-2-yl) 9H-purin-6-amine The product from step (ii) (30g) was dissolved in dry DCM (200ml). The solution was stirred at rt whilst iV-bromosuccinimide (27g) was added portion wise. The mixture was stirred at rt overnight. 20%(w/v)-Sodium sulfate (200ml) was added and the separated aqueous phase extracted with DCM. The combined organic phase was washed with saturated NaHCO ₃ solution and brine. After concentration in vacuo, the residue was dissolved in EtOAc, washed with water, brine and dried. The solution was filtered through silica gel. The filtrate was concentrated in vacuo and dissolved in a mixture of diethyl ether and isohexane (1/1, 200ml) to give the subtitle compound (26g). The solvent was removed to give a residue, which was purified by column chromatography (EtOAc/isohexane), which afforded 2.5g. The solids were combined to give the subtitle compound as a yellow solid. Yield 28.5g. mp 148-5O ⁰ C

¹ H NMR δ (CDCl ₃ ) 5.59-5.64 (3H, m), 4.32 (2H, m), 4.17 (IH, m), 3.74 (IH, m), 3.08 (IH, m), 2.13 (IH, d), 1.48 - 1.83 (8H, m), 0.98 (3H, t).

(iv) 2-Butoxy-8-methoxy-9-(tetrahydro-2H-pyran-2-yl) 9H-purin-6-amine Sodium (3.7g) was added to absolute methanol (400ml) under a nitrogen atmosphere. To this solution was added the product (28.5g) from step (iii) and the mixture was stirred at 65 ⁰ C for 9h. The mixture was concentrated in vacuo and 500ml of water added. The aqueous phase was extracted with EtOAc and washed with brine and dried. The subtitle compound was obtained after crystallisation from diethyl ether. Yield 14.2g. ¹ H NMR δ (CDCl ₃ ) 5.51(1H, dd), 5.28 (2H, brs), 4.29 (2H, t), 4.11 - 4.14 (4H, m), 3.70 (IH, m), 2.76 - 2.80 (IH, m), 2.05 (IH, d), 1.47 - 1.81 (8H, m), 0.97 (3H, t).

(v) 2-Butoxy-8-methoxy-9H-purin-6-amine, TFA salt

The product from step (iv) (24g) was dissolved in absolute methanol (300ml) and 30ml of TFA was added. The reaction mixture was stirred at rt for 3 days and concentrated in vacuo. The subtitle compound was obtained as a white crystalline solid after trituration with methanol/EtOAc. Yield 2 Ig.

¹ H NMR δ (CD ₃ OD) 4.48 (2H, t), 4.15 (3H, s), 1.80 (2H, quintet), 1.50 (2H, sextet), 0.99 (3H, t).

(vi) 2-[3-(6-Amino-2-butoxy-8-methoxy-9H-purin-9-yl)propyl]-lH-is oindole- l,3(2H)-dione

The product from step (v) (15g) was dissolved in dry DMF (200ml) and 18g of K ₂ CO ₃ added. After the suspension was stirred at rt for 15min, 2-(3-bromopropyl)-lH-isoindole-l,3(2H)- dione (14g) was added the the suspension vigorously stirred at rt for 10 h. The reaction mixture was extracted with EtOAc, washed with water and brine and dried. The subtitle compound was obtained after crystallisation from EtOAc/diethyl ether. Yield 16g. ¹ H NMR δ (DMSO-d ₆ ) 7.83 (4H, m), 6.73 (2H, brs), 4.06 (2H, t,), 4.01 (3H, s), 3.89 (2H, t), 3.58 (2H, t), 2.07-2.14 (2H, m), 1.55-1.62 (2H, m), 1.31-1.40 (2H ₅ m), 0.90 (3H, t).

(vii) 9-(3-Aminopropyl)-2-butoxy-8-methoxy-9H-ρurin-6-amine

The product from step (vi) (Ig) was dissolved in ethanol (10ml) and hydrazine monohydrate (ImI) was added and stirred at ambient temperature for 1Oh. The resultant was concentrated under reduced pressure and the residue suspended in DCM (10ml) and stirred for Ih. The suspension was filtered, washed with DCM. The solution was washed with water and dried. The solution was concentrated under reduced pressure to give the subtitled compound. Yield 700mg.

¹ H NMR δ (DMSO-d ₆ ) 6.77 (2H, brs), 4.16 (2H, t), 4.05 (3H, s), 3.89 (2H, t), 2.46-2.52 (2H, m), 1.61-1.76 (4H, m), 1.35-1.45 (2H, m), 0.92 (3H, t).

(viii) [4-({[3-(6-Amino-2-butoxy-8-methoxy-9H-purin-9- y l)propy 1] amino } methy l)phenyl] acetic acid

The product from step (vii) (9.7g) and (4-formylphenyl)acetic acid (5.4g) were dissolved in TηF (100ml) and stirred at rt for 4h. Sodium borohydride (1.9g) and 5 drops of methanol was added and stirred at a rt overnight. The mixture was quenched with water and concentrated under reduced pressure. Water was added and washed with diethyl ether. 0. IN- HCl was added to acidify the solution to pη 6. The suspension was filtered and the solid collected and dried under reduced pressure to give the subtitle compound. Yield 13g. ¹ H NMR δ (DMSO-d ₆ ) 7.14 - 7.22 (4η, m), 6.75 (2H, brs), 4.12 (2H, t), 4.03 (3H, s), 3.88 (2H, t), 3.62 (2H, s), 3.38 (2H, s), 1.34 - 2.47 (8H, m), 0.91 (3H, t).

(ix) Methyl [4-({[3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H-purin-9- yl)propyl]amino}methyl)phenyl]acetate

The product from step (viii) (13g) was dissolved in methanol (100ml) and 4N-ηC1 in dioxane (10ml) added. The reaction mixture was stirred at rt for 24h. The resultant was concentrated under reduced pressure and aqueous NaHCO ₃ added to pH 8. The suspension was filtered and the solid collected and dried under reduced pressure to give the subtitle compound. Yield 1 Ig. ¹ HNMR δ (DMSO-d ₆ ) 7.15 - 7.25 (4H, m), 6.35 (2H, brs6), 4.12 (2H, t), 3.71 (2H, t), 3.62 (3H, s), 3.62 (2H ₅ s), 3.60 (2H ₅ s), 2.47 (2H ₅ m), 1.34 - 1.80 (6H, m), 0.90 (3H ₅ 1).

(x) Methyl [4-({[3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H-purin-9- yl)propyl] [(4-methylpiperazin- 1 -yl)acetyl] amino } methyl)phenyl] acetate

The product from step (ix) (200mg) was suspended in MeCN. Chloroacetyl chloride (0.02ml) added and the mixture stirred at rt for 4h. The mixture was concentrated under reduced pressure, piperazine (0.02 ml) in DMSO (ImI) was added and the mixture heated at 60 ⁰ C for 24h. The mixture was purified by RPHPLC. Yield 80mg. s ¹ R NMR δ (DMSO-dg) 10.02 (IH, brs), 7.10 - 7.20 (4H, m), 6.30 (2H, brs), 4.52 (2H, m), 4.15 (3H, t), 3.60 - 3.66 (7H, m), 3.27 (4H, m), 2.98 (4H, m), 2.73 (4H, m), 2.61 (3H, s), 1.33 - 1.94 (6H, m), 0.92 (3H, t). MS: APCI (+ve): 583 (M+H).

o Example 2

Methyl (4-{ [ [3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H-purin-9-yl)propyl] (λyV- dimethylglycyl)amino]methyl}phenyl)acetate s

The product of example 1, step (ix) (200mg) was suspended in MeCN. AζN-dimethylglycyl chloride hydrochloride (1 lOmg) and triethylamine (0.19ml) were added and the mixture stirred at rt for 1Oh. The mixture was purified by RPηPLC. Yield lOOmg. ¹ H νMR δ (DMSO-de) 7.07 - 7.22 (4H, m), 6.43 (2H, brs), 4.55 (2H, s), 4.13 (2H, t), 3.63 - 0 3.69 (4H, m), 3.60 (3H, s), 3.29 (2H ₃ m), 3.01 (2H, s), 2.14 (2H, s), 1.31 - 1.97 (6H, in), 0.90 (3H, t). MS: APCI (+ve): 528 (M+H).

Example 3 5

Methyl [4-({ [3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H-purin-9-yl)pr opyl] [(1- methyIpiperidin-4-yl)carbonyl] amino}methyl)phenyl] acetate

₅

The title compound was prepared by the method of example 2 using l-methylpiperidine-4- carbonyl chloride hydrochloride, yield 50mg.

¹ R NMR δ (DMSO-d ₆ ) 7.04 - 7.24 (4H, m), 6.45 (2H, brs), 4.51 (2H, s), 4.13 (2H, t), 3.60 -

3.65 (7H, m), 3.17 - 3.31 (4H, m), 2.66 (2H, s), 2.07 (3H, s), 1.35 - 2.02 (1 IH, m), 0.90 (3H, o t).

MS: APCI (+ve): 568 (M+H).

Example 4

Methyl [4-({ [3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H-purin-9-yl)propyl] [4- (dimethylamino)butanoyl] amino} methyl)phenyl] acetate

o The title compound was prepared by the method of example 2 using 4- (dimethylamino)butanoyl chloride hydrochloride, yield 30mg.

¹ H NMR δ (DMSO-de) 7.05 - 7.24 (4H, m), 6.40 (2H ₅ brs), 4.55 (2H, s), 4.12 (2H, t), 3.39 - 3.65 (7H ₃ m), 3.23 (2H, m), 2.10 - 2.27 (4H, m), 2.04 (6H, s), 1.33 - 1.93 (8H, m), 0.91 (3H, t).

MS: APCI (+ve): 556 (M+H).

Example 5

Methyl (4-{[[3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H-purin-9-yl)pr opyl](iV _; λ- dimethyl-β-alanyl)amino]methyl}phenyl)acetate

The title compound was prepared by the method of example 2 using N,N-dimethyl-β-alanyl chloride hydrochloride, yield 55mg.

¹ H νMR δ (DMSO-d ₆ ) 7.06 - 7.24 (4H, m), 6.40 (2H, brs), 4.51 (2H, s), 4.12 (2H, t), 3.62 -

3.69 (7H ₃ m), 3.60 (3H, s), 3.23 (2H, m ), 2.40 (4H, m), 2.05 (6H, s), 1.34 - 1.93 (6H, m),

0.90 (3H, t). MS: APCI (+ve): 542 (M+H).

Example 6

Methyl [4-({ [3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9J?-purin-9-yl)propyl ] [λyV-bis(2- hydroxyethyl)glycyl]amino}methyl)phenyl]acetate

The title compound was prepared by the method of example 1 using 2,2'-iminodiethanol, yield 30mg.

¹ H NMR δ (DMSOd ₆ ) 7.09 - 7.20 (4H, m), 4.59 (2H, brs), 4.22 (2H, m), 3.78 (2H, t), 3.64 (3H ₅ s), 3.45 - 3.61 (10H ₅ m), 2.71 (4H, m), 1.44 - 2.10 (6H, m), 0.95 (3H, t). MS: APCI (+ve): 588 (M+H).

Example 7

Methyl {4-[([3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H-purin-9-yl)pr opyl]{[4-(2- hydroxyethyl)piperazin-l-yl]acetyl}amino)methyl]phenyl}aceta te

The title compound was prepared by the method of example 1 using 2-piperazin-l-ylethanol, yield 52mg.

¹ H NMR δ (DMSO-de) 9.87 (IH, brs), 7.06 - 7.21 (4H, m), 6.41 (2H, brs), 4.55 (2H, s), 4.22 (2H ₅ m), 3.63 - 3.69 (4H ₅ m), 3.60 (3H ₅ s), 3.20 (2H ₅ m), 3.04 (2H, s), 1.36 - 2.37 (18H, m), 0.90 (3H ₅ 1). MS: APCI (+ve): 613 (M+H).

Example 8

Methyl {4-[([3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H-purin-9-yl)pr opyl]{[4- (methylsulfonyl)piperazin-l-yl]acetyl}amino)methyl]phenyl}ac etate

5

The title compound was prepared by the method of example 1 using 1- (methylsulfonyl)piperazine, yield 25mg.

¹ H NMR δ (DMSO-de) 7.07 - 7.24 (4H, m), 6.44 (2H, brs), 4.54 (2H, s), 4.12 (2H, m), 3.63 - 3.67 (4H, m), 3.60 (3H, s), 3.15 (2H, s), 3.03 (4H, m), 2.83 (2H, s), 2.40 (4H, m), 1.33 - 1.90 io (6H, m), 0.90 (3H, t).

MS: APCI (+ve): 647 (M+H).

Example 9

Methyl [3-({ [3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9#-purin-9-yl)propyl] [(1- methylpiperidin-4-yl)carbonyl]amino}methyl)phenyl]acetate

20 (i) tert-Butyl [3-(6-amino-2-butoxy-8-methoxy-9H ^' -purin-9-yl)propyl]carbamate

The product from example 1 step (v) (1.5g), 1.4g of K ₂ CO ₃ and tert-bntyl (3- bromopropyl)carbamate (Ig) were heated at 5O ⁰ C in DMF (10ml) for 3h. The reaction mixture was cooled to rt, extracted with EtOAc, washed with water and dried. The solvent

was removed to give a residue, which was purified by column chromatography (methanol/DCM), which afforded the subtitle compound. Yield l.lg. ¹ H NMR δ (DMSO-d ₆ ) 6.82 (IH, t), 6.77 (2H, s), 4.17 (2H, t,), 4.04 (3H, s), 3.83 (2H, t), 2.90 (2H, m), 1.79 (2H, m), 1.65 (2H, m), 1.41 (2H, m), 1.37 (9H, s), 0.92 (3H, t). s

(ii) 6-Amino-9-(3-aminopropyl)-2-butoxy-7,9-dihydro-8H-purin-8-on e The product from step (i) (l.lg) was dissolved in methanol/DCM (1/1, 40ml). 4N-ηC1 in dioxane (10ml) was added and the mixture stirred at rt for 2Oh. The resultant was concentrated under reduced pressure, which afforded the subtitle compound. Yield 0.9g. o ¹ H NMR 6 (DMSOd ₆ ) 10.71 (IH, brs), 7.88 (2H, brs), 4.22 (2H, t,), 3.75 (2H, t), 2.77 (2H, m), 1.96 (2H, m), 1.36 - 1.70 (4H, m), 0.92 (3H, t).

(iii) Methyl [3-({[3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H-purin-9- yl)propyl]amino}methyl)phenyl]acetate s The product from step (ii) (3.Ig) and methyl (3-formylphenyl)acetate (1.6g) were dissolved in NMP (30ml) and stirred for 15min. Sodium triacetoxyborohydride (3.7g) was added and the mixture stirred at rt for 20 h. After addition of methanol (1 ml), the mixture was purified by SCX, which afforded the subtitle compound. Yield 3.1g.

¹ H NMR δ (DMSO-d ₆ ) 7.27 - 7.21 (3H, m), 7.13 (IH, m), 6.46 (2H, brs), 4.12 (2H, t), 3.73 0 (2H, t), 3.70 (2H, s), 3.64 (2H, s), 3.61 (3H, s), 2.54 (2H, t), 1.82 (2H, m), 1.62 (2H, m), 1.37 (2H, m), 0.90 (3H, t).

(iv) Methyl [3-({[3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H-purin-9- yl)propyl][(l-methylpiperidin-4-yl)carbonyl]amino}methyl)phe nyl]acetate 5 The product from step (iii) (O.lg), diisopropyl ethylamine (0.1ml) and l-methylpiperidine-4- carboxylic acid hydrochloride (45mg) were dissolved in NMP (3ml) then ηATU (130mg) added to the mixture. The mixture was stirred at rt for 5h then purified by SCX and RPηPLC, which afforded the title compound. Yield 70mg.

¹ H NMR δ (DMSO- d ₆ ) 7.23 (IH, t), 7.12 (IH, d), 7.03 (IH, s), 7.02 (IH, d), 6.15 (2H, brs), o 4.50 (2H, s), 4.16 (2H, t), 3.65 (2H, t), 3.61 (2H, s), 3.60 (3H, s), 3.25 (2H, t), 2.68 (2H, m),

2.10 (3H, s), 1.86- 1.96 (2H, m), 1.63 (5H, m), 1.42 (4H, m), 0.91 (3H, t).

MS: APCI (+ve): 568 (M+l).

Example 10

Methyl [3-({ [3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9iT-purin-9-yl)propyl ] [(1- methylpiperidin-4-yl)carbonyl] amino}methyl)phenyl] acetate

The title compound was prepared by the method of example 10 using N-(tert- butoxycarbonyl) glycine, yield 160mg.

¹ H NMR δ (DMSO- d ₆ ) 9.69 (IH, s), 7.27 (IH, m), 7.17 (IH, m), 7.09 (2H, m), 6.35 - 6.25 (IH, m), 6.14 (2H, brs), 4.54 (2H, s), 4.20 (2H, t), 3.83 (2H, d), 3.69 (2H, t), 3.65 (2H, s), 3.64 (3H, s), 3.31 (2H, t), 1.95 (2H, m), 1.68 (2H, m), 1.43 (2H, m), 1.40 (9H, s), 0.95 (3H, t). MS: APCI (+ve): 600 (M+l).

Example 11

Methyl (3-{[[3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9Jϊ-purin-9- yl)propyl] (glycyl)amino] methyl}phenyl)acetate

The product from example 10 (150mg) was dissolved in methanol (2ml) and 4N HCl in dioxane added. The mixture was stirred at rt for 3h and purified by RPHPLC, which afforded the title compound. Yield 20mg.

¹ HNMR δ (DMSO- d ₆ ) 7.24 (IH, m), 7.13 (IH, m), 7.05 (2H, m), 6.13 (2H, brs), 4.50 (2H, s), 4.17 (2H, s), 3.66 (2H, t), 3.62 (2H, s), 3.61 (3H, s), 3.33 (2H, s), 3.24 - 3.31 (2H, m), 1.92 (2H, m), 1.65 (2H, m), 1.40 (2H, m), 0.93 (3H, t). MS: APCI (+ve): 500 (M+l).

Example 12

Methyl [3-({ [3-(6-amino-2-butoxy-8-oxo-7,8-dihydr o-9H-purm-9- yl)propyl][(methylthio)acetyl]amino}methyl)phenyl] acetate

The title compound was prepared by the method of example 10 using (methylthio)acetic acid, yield 170mg.

¹ H NMR δ (DMSO- d ₆ ) 7.24 (IH, m), 7.14 (IH, m), 7.07 (2H, m), 6.13 (2H, brs), 4.48 - 4.60

(2H, m), 4.17 (2H, t), 3.67 (2H, t), 3.62 (2H, s), 3.61 (3H, s), 3.33 (2H, s), 3.30 (2H, t), 2.09 (3H, s), 1.90 - 2.02 (2H ₅ m), 1.65 (2H, m), 1.40 (2H, m), 0.92 (3H, t).

MS: APCI (+ve): 531 (M+l).

Example 13

Methyl [3-({ [3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9ϋ-purin-9- yl)propyl] [(methylsulfinyl)acetyl] amino}methyl)phenyl] acetate s

The product from example 12 (150mg) was dissolved in DCM (10ml) and methanol (2ml) and mCPBA (0. Ig) added. The mixture was stirred at rt for 3h then purified by RPHPLC, which afforded the title compound. Yield 50 mg.

¹ H NMR δ (DMSO- d ₆ ) 7.00 - 7.31 (4H, m), 6.14 (2H, brs), 4.46 - 4.70 (2H, m), 4.17 (2H, t), iϋ 3.92 (2H, s), 3.67 (2H, s), 3.61 (3H, s), 3.02 (4H, m), 2.62 (3H, s), 1.85 - 2.11 (2H, m), 1.65

(2H, m), 1.41 (2H, m), 0.93 (3H, t).

MS: APCI (+ve): 547 (M+l).

Example 14

15

Methyl [3-({ [3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9-ff-purin-9- yl)propyl][(methylsulfonyl)acetyl]amino}methyl)phenyl]acetat e 0

The product from example 12 (150mg) was dissolved in DCM (10ml) and methanol (2ml) and mCPBA (0. Ig) added. The mixture was stirred at rt for 3h then purified by RPHPLC, which afforded the title compound. Yield 40mg.

¹ B. NMR δ (DMSO- d ₆ ) 7.05 - 7.39 (4H, m), 6.15 (2H, brs), 4.60 (2H, m), 4.35 (2H, m), 4.17 (2H, t), 3.68 (2H, s), 3.62 (3H, s), 3.11 (3H, s), 3.03 (4H, m), 1.84 - 2.05 (2H, m), 1.65 (2H, m), 1.41 (2H, m), 1.10 (3H, t). MS: APCI (+ve): 563 (M+l).

Example 15

Methyl [3-({[3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9Jy-purin-9-yl)p ropyl] [3- (methylthio)propanoyl] amino} methyl)phenyl] acetate

The title compound was prepared by the method of example 10 using 3- (methylthio)propanoic acid, yield 130mg. ¹ H NMR δ (DMSO- d ₆ ) 7.25 (IH, m), 7.14 (IH, m), 7.07 (2H, m), 6.13 (2H, brs), 4.53 (2H, s), 4.17 (2H, t), 3.67 (2H, t), 3.62 (2H, s), 3.61 (3H, s), 3.31 (2H, t), 2.68 (2H, m), 2.58 (2H, m), 2.01 (3H, s), 1.99 - 1.89 (2H, m), 1.65 (2H, m), 1.41 (2H, m), 0.93 (3H, t). MS: APCI (+ve): 545 (M+l).

Example 16

Methyl [3-({ [3-(6-amino-2-butoxy-8-oxo~7,8-dihydro-9H-purin-9-yl)propyl] [3- (methylsulfonyl)propanoyl] amino}methyl)phenyl] acetate

The title compound was prepared by the method of example 14 using the product from example 15, yield 60mg.

¹ H NMR δ (DMSO- d ₆ ) 7.24 (IH, m), 7.14 (IH, m), 7.06 (2H, m), 6.13 (2H, brs), 4.61 - 4.50 (2H, m), 4.16 (2H, t), 3.67 (2H, t), 3.62 (2H, s), 3.61 (3H, s), 3.34 (4H, m), 2.92 (3H, s), 2.80 (2H, t), 1.89 - 2.00 (2H, m), 1.65 (2H, m), 1.40 (2H, m), 0.92 (3H, t). MS: APCI (+ve): 577 (M+l).

Example 17

Methyl [3-({[3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H-purin-9-yl)pr opyl] [N- (methylsulfonyl)glycyl] amino} methyl)phenyl] acetate

The product from example 11 (50mg) was dissolved in NMP (ImI), then pyridine (0.07ml) and methanesulfonic anhydride (29mg) added. The mixture was stirred at rt for 2Oh then purified by RPHPLC, which afforded the title compound. Yield 15mg

¹ B. NMR δ (DMSO- d ₆ ) 7.25 (IH, m), 7.15 (IH, m), 7.07 (2H, m), 6.15 (2H, brs), 4.53 (2H, s), 4.17 (2H, t), 3.91 (2H, s), 3.67 (2H, t), 3.63 (2H, s), 3.62 (3H, s), 3.31 (2H, t), 2.92 (3H, s), 1.89 - 1.99 (2H, m), 1.65 (2H, m), 1.41 (2H, m), 0.93 (3H, t). MS: APCI (+ve): 576 (M+l).

Example 18

tert-Butyl 4-{ [3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H-purin-9-yl)propyl] [3-(2- methoxy-2-oxoethyl)benzyl]amino}-4-oxobutanoate

The title compound was prepared by the method of example 10 using 4-tert-butoxy-4- oxobutanoic acid, yield 17mg.

¹ H NMR δ (DMSO- d ₆ ) 7.22 (IH, m), 7.12 (IH, m), 7.05 (2H, m), 6.11 (2H, brs), 4.51 (2H, s), 4.16 (2H, t), 3.65 (2H, t), 3.60 (2H, s), 3.60 (3H, s), 3.29 (2H, m), 2.50 (2H, m), 2.42 (2H, m), 1.85 - 1.98 (2H, m), 1.64 (2H, m), 1.39 (2H, m), 1.36 (9H, s), 0.91 (3H, t). MS: APCI (+ve): 599 (M+ 1).

Example 19

4-{[3-(6-Amino-2-butoxy-8-oxo-7,8-dihydro-9 _J H-purin-9-yI)propyl][3-(2-methoxy-2- oxoethyl)benzyl] amino}-4-oxobutanoic acid

The product from example 18 (140mg) was dissolved in DCM (ImI) and TFA (0.2ml) added. The mixture was stirred at rt for 2h. The solution was washed with saturated aqueous NaHCO ₃ solution and dried. The mixture was purified by RPHPLC, which afforded the title compound. Yield 80mg.

¹ HNMR δ (DMSO- d ₆ ) 9.66 (IH, s), 7.22 (IH, m), 7.12 (IH, m), 7.05 (2H, m), 4.52 (2H, brs), 4.16 (2H, t), 3.65 (2H, t), 3.61 (2H, s), 3.60 (3H, s), 3.29 (2H, m), 2.54 (2H, m), 2.46 (2H, m), 1.85 - 1.98 (2H, m), 1.64 (2H, m), 1.39 (2H, m), 0.91 (3H, t). MS: APCI (+ve): 543 (M+l).

Example 20

Methyl 3-{ [3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H-purin-9-yl)propyl] [3-(2-methoxy- 2-oxoethyl)benzyl]amino}-3-oxopropanoate

(i) tert-Butyl 3-{[3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H-purin-9- yl)propyl][3-(2-methoxy-2-oxoethyl)benzyl]amino}-3-oxopropan oate The subtitle compound was prepared by the method of example 10 using 3~tert-butoxy-3- oxopropanoic acid. Yield lOOmg. MS: APCI (+ve): 585 (M+l).

(ii) Methyl 3-{[3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H-purin-9-yl)prop yl][3- (2-methoxy-2-oxoethyl)benzyl]amino} -3-oxopropanoate

The product from step (i) (lOOmg) was dissolved in methanol (3ml) and 4N-ηC1 in dioxane added. The mixture was stirred at rt for 5h and purified by RPHPLC, which afforded the title compound. Yield 80mg

¹ H NMR δ (DMSO- d ₆ ) 9.68 (IH, s), 7.23 (IH, m), 7.13 (IH, m), 7.06 (2H, m), 6.11 (2H, brs), 4.51 (2H, s), 4.16 (2H, t), 3.65 (2H, t), 3.60 (6H, s), 3.27 (2H, t), 3.00 (2H, s), 2.99 (2H, m), 1.85 - 1.98 (2H, m), 1.64 (2H ₅ m), 1.39 (2H, m), 0.91 (3H, t).

MS: APCI (-We): 543 (M+l).

Example 21

Methyl [3-({acetyl[3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9H-purin-9 - yl)propyl]amino}methyl)phenyl]acetate

The product from example 20 step (i) (lOOmg) was dissolved in DCM (ImI) and TFA (0.2ml) added. The mixture was stirred at rt for 2h. The solution was washed with saturated aqueous

NaHCO ₃ and dried. The mixture was purified by RPHPLC, which afforded the title compound.

Yield 30mg

¹ H NMR δ (DMSO- d ₆ ) 7.01 - 7.29 (4H, m), 6.12 (2H, brs), 4.50 (2H, s), 4.15 (2H, t), 3.65

(2H, t), 3.61 (2H, s), 3.60 (3H, s), 3.26 (2H, t), 2.00 (3H, s), 1.83 - 1.99 (2H, m), 1.64 (2H, m), 1.39 (2H, m), 0.91 (3H, t).

MS: APCI (+ve): 485 (M+l).

Example 22

Methyl (34[[3-(6-amino-2-butoxy-8-oxo-7,8-dihydro-9#-purin-9- yl)propyl] (methylsulfonyl)amino] methyl}phenyl)acetate

The title compound was prepared by the method of example 17 using product example 9 step (iii) (lOOmg) and methanesulfonic anhydride (76mg). yield 60mg. s ¹ H NMR δ (DMSO- d ₆ ) 7.33 - 7.49 (4H, m), 6.33 (2H, brs), 4.53 (2H, s), 4.38 (2H, t), 3.84 (2H, s), 3.82 (2H, m), 3.82 (3H, s), 3.37 (2H, t), 3.12 (3H, s), 2.10 (2H, m), 1.86 (2H m), 1.62 (2H, m), 1.14 (3H, t). MS: APCI (+ve): 521 (M+l).

o Example 23

(4-{[[3-(6-Amino-2-butoxy-8-oxo-7,8-dihydro-purin-9-yl)[2 R]-propyI]-(pyrrolidine-2- 5 carbonyl)-amino]-methyl}-phenyl)-acetic acid methyl ester

The product of example 1, step (ix) (300mg) and pyrrolidine- 1,2-dicarboxylic acid l-(R)-teτt- butyl ester (146mg) were dissolved in DCM (10ml) and HATU (258mg) added. After Ih, more HATU (258mg) and ^-pyrrolidine- 1,2-dicarboxylic acid 1-tert-butyl ester (146mg) 0 were added to the miture. The mixture was stirred at rt for 16h and TFA (5ml) added and stirred for 4h. The reaction mixture was concentrated in vacuo to dryness then redissolved in methanol before being purified by RPHPLC ₅ to give the title compound. Yield 19mg. ¹ H NMR δ (DMSO- d ₆ ) 8.19 (IH, s), 7.27 - 7.03 (5H, m), 6.46 (2H ₅ d ₅ J= 14.9 Hz), 4.71 - 4.49 (2H ₅ m), 4.41 (IH ₅ d) ₅ 4.20 - 4.04 (4H ₅ m) ₅ 3.71 - 3.60 (4H, m) ₅ 3.47 - 3.33 (2H ₅ m), 3.34 5 - 3.26 (2H, m), 3.26 - 3.18 (2H, m) ₅ 3.17 - 3.07 (2H ₅ m), 2.92 - 2.81 (IH ₅ m), 2.19 - 2.02 (2H,

m), 2.02 - 1.86 (2H, m), 1.82 - 1.69 (2H, m), 1.69 - 1.56 (2H, m), 1.45 - 1.32 (2H, m), 0.94

0.88 (3H, m).

MS: APCI (+ve): 540 (M+l).

Example 24

(4-{[[3-(6-Amino-2-butoxy-8-oxo-7,8-dihydro-purin-9-yl)-p ropyl][2S,4R](4-hydroxy- pyrrolidine^-carbonyty-aminoj-methylj-phenyty-acetic acid methyl ester

The product of example 1, step (ix) (0.27 g) was dissolved in DCM (10ml) and treated with (2?)-4-triethylsilanyloxy-pyrrolidine-l,2-dicarboxylic acid 1-fS^-tert-butyl ester (211mg) and HATU (232mg).The reaction was stirred at rt for 16h and TFA (2ml) added and stirred for 4h. The reaction mixture was concentrated to dryness in vacuo purifed by RPHPLC to give the title compound. Yield 114mg.

¹ H NMR δ (DMSO- d ₆ ) 8.22 (IH ₅ s), 7.28 - 7.02 (4H, m), 6.46 (2H, d), 4.61 (IH, s), 4.60 - 4.36 (IH, m), 4.27 - 4.19 (2H, m), 4.17 - 4.06 (3H, m), 3.70 - 3.61 (4H, m), 3.34 - 3.23 (2H, m), 3.19 - 3.06 (2H, m), 2.00 - 1.86 (2H, m), 1.87 - 1.73 (2H, m), 1.70 - 1.56 (2H, m), 1.44 - 1.31 (2H, m), 0.96 - 0.84 (3H, m). MS: APCI (+ve): 556 (M+l).

Example 25

(4-{ [ [3-(6-Amino-2-butoxy-8-oxo-7,8-dihydro-purin-9-yI)-propyl] [2S] -(1-methyl- pyrroIidine-2-carbonyl)-amino]-methyl}-phenyl)-acetic acid methyl ester

The product of example 1, step (ix) (0.43 g), l-methyl-pyrrolidine-2-carboxylic acid (0.13g) and HATU (0.37g) were stirred in DCM (5ml) at rt for 7 days. The reaction mixture was purified by SCX and RPHPLC, to give the title compound. Yield 24mg. ¹ H NMR δ (DMSO- d ₆ ) 9.92 (IH, d), 9.61 (IH, s), 7.30 - 7.03 (5H, m), 6.44 (2H, s), 4.67 - 4.56 (2H, m), 4.54 - 4.42 (2H, m), 4.15 - 4.05 (4H, m), 3.69 - 3.58 (4H, m), 2.84 - 2.73 (4H, m), 2.05 (3H, s), 2.10 - 1.97 (2H, m), 1.97 - 1.84 (2H, m), 1.86 - 1.73 (2H, m), 1.66 - 1.53 (2H, m), 1.37 - 1.24 (2H, m), 0.96 - 0.83 (3H, m). MS: APCI (+ve): 554 (M+ 1).

Example 26

(4-{[[3-(6-Amino-2-butoxy-8-oxo-7,8-dihydro-purin-9-yl)-p ropyl]-(3-piperazin-l-yl- propionyl)-amino]-methyl}-phenyl)-acetic acid methyl ester

The product of example 1, step (ix) (0.27 g) was dissolved in DCM (10ml) and treated with 4-

(2-carboxy-ethyl)-piperazine-l-carboxylic acid tert-butyl ester (0.16 g) and HATU (0.23g).

The reaction was stirred at rt for 16h, before 2mls of TFA added. The mixture was purifed by

RPHPLC, to give the title compound. Yield 3mg.

¹ H NMR δ (DMSO- d ₆ ) 9.93 (IH, d), 7.27 - 7.06 (4H, m), 6.52 - 6.41 (2H, m), 4.60 (IH, s),

4.48 (IH, s), 4.13 (2H, s), 3.71 - 3.59 (4H, m), 3.61 (3H, s), 3.43 - 3.16 (1OH, m), 2.87 - 2.75

(2H, m), 2.02 - 1.91 (2H, m), 1.91 - 1.80 (2H, m), 1.68 - 1.58 (2H, m), 1.42 - 1.31 (2H, m),

0.91 (3H, t).

MS: APCI (+ve): 583 (M+l).

The compounds of Examples 27 to 103 were prepared by processes analogous to Example 1, step (x) using commercially available amines.

Biological Assay

Human TLR7 assay

Recombinant human TLR7 was stably expressed in a HEK293 cell line already stably s expressing the pNiFty2-SEAP reporter plasmid; integration of the reporter gene was maintained by selection with the antibiotic zeocin. The most common variant sequence of human TLR7 (represented by the EMBL sequence AF240467) was cloned into the mammalian cell expression vector pUNO and transfected into this reporter cell-line. Transfectants with stable expression were selected using the antibiotic blasticidin. In this o reporter cell-line, expression of secreted alkaline phosphatase (SEAP) is controlled by an NFkB/ELAM-1 composite promoter comprising five NFkB sites combined with the proximal ELAM-I promoter. TLR signaling leads to the translocation of NFkB and activation of the promoter results in expression of the SEAP gene. TLR7-specific activation was assessed by determining the level of SEAP produced following overnight incubation of the cells at 37°C s with the standard compound in the presence of 0.1 % (v/v) dimethylsulfoxide (DMSO). Concentration dependent induction of SEAP production by compounds was expressed as the log of the minimal effective concentration of compound to induce SEAP release (pMEC). For example Compounds of Examples : 1, 4, 7 and 18 have pMEC >7.7