8-alkynylxanthines and derivatives

1. A compound corresponding in structure to formula (Ia)

or a pharmaceutically acceptable salt, diastereomer or enantiomer thereof wherein,

R 2 is hydrogen or methyl;

R 3 is methyl, propargyl, butynyl, or cyanomethyl;

R 4 is imidazol-2-yl or thien-3-yl optionally substituted with one or more substituents selected from halogen, methyl, or methoxy;

or

R 4 is phenyl which is substituted in meta position to its attachment position to the triple bond with a residue selected from the group consisting of amino, —OR 5 and methyl; and which in para position is unsubstituted or substituted with methoxy, methyl, or fluoro;

or

R 4 is phenyl that is annelated in 3- and 4-position to a second heterocyclic 5 or 6-membered ring which contains one or more oxygen atoms thus forming a bicyclic ring system, which can be substituted with a methyl, methoxy or hydroxyl group;

R 5 is hydrogen or methyl;

or

R 5 is (C 1 -C 4 )-alkyl substituted in one or more places, in the same way or differently, with methoxy, carboxy, hydroxyl or a phosphate ester thereof, or with —NR 6 R 7 , and

R 6 and R 7 are independently hydrogen, or (C 1 -C 3 )-alkyl; or

R 6 and R 7 together with the nitrogen atom to which they are attached form a five or six membered ring which may contain one or two additional ring forming heteroatoms selected from N and O, and the five or six membered ring may be unsubstituted or substituted with one or more residues selected from the group consisting of (C 1 -C 3 )-alkyl; hydroxyl(C 1 -C 3 )-alkyl; amino(C 1 -C 3 )-alkyl; (C 1 -C 3 )-alkoxy(C 1 -C 3 )-alkyl; halo(C 1 -C 3 )-alkyl; mono(C 1 -C 2 )-alkylamino(C 1 -C 3 )-alkyl; and di(C 1 -C 2 )-alkylamino(C 1 -C 3 )-alkyl.

2. A compound corresponding in structure to formula (Ia)

or a pharmaceutically acceptable salt, diastereomer or enantiomer thereof wherein,

R 2 is hydrogen, methyl, NR 6 R 7 ; or

R 2 is (C 2 -C 4 )-alkyl, (C 2 -C 4 )-alkenyl, (C 2 -C 4 )-alkynyl; or

R 2 is methyl which is substituted with a residue selected from the group consisting of cyano, carboxy, (C 3 -C 5 )-cycloalkyl, (C 1 -C 2 )-alkoxycarbonyl, (C 1 -C 2 )-alkylcarbonyl, mono(C 1 -C 2 )-alkylamino, di(C 1 -C 2 )-alkylamino, a 3 to 5-membered heterocyclyl ring and a 5 to 6-membered heteroaryl ring; or

R 2 is ethyl, which is substituted in one or more places, in the same way or differently, with a substituent selected from the group consisting of fluoro; chloro; bromo; cyano; carboxy; methylcarbonyl; methoxycarbonyl; mono(C 1 -C 2 )-alkylamino; di(C 1 -C 2 )-alkylamino; —OR 8 ; a 3 to 5-membered oxygen-containing heterocyclyl; hydroxyl; a phosphate ester or a substituted or unsubstituted naturally occurring amino acid ester of said hydroxyl group; or

R 2 is propyl or butyl, which is substituted in one or more places, in the same way or differently, with a substituent selected from the group consisting of fluoro; chloro; bromo; cyano; carboxy; —OR 8 ; hydroxyl or a phosphate ester or an ester of a substituted or unsubstituted naturally occurring amino acid of said hydroxyl group;

R 3 is methyl, propargyl, butynyl, or cyanomethyl;

R 4 is phenyl which is substituted in meta and/or in para position to its attachment to the triple bond with chloro, methyl, or a group —OR 5 ; or

R 4 is thien-3-yl, furan-3-yl or a imidazol-2-yl, each of which is optionally substituted at one of its ring forming carbon atoms with one or more substituents selected from the group consisting of halogen, methyl, and methoxy; and wherein the imidazol-2-yl residue is optionally substituted in its N1 position by a methyl group;

R 5 is methyl, ethyl, or (C 1 -C 4 )-alkyl which is substituted with OH, a phosphate ester thereof or —NR 6 R 7 ;

R 6 and R 7 are independently hydrogen, methyl or ethyl; and

R 8 is (C 1 -C 3 )-alkyl or (C 1 -C 3 )-alkoxy-(C 1 -C 3 )-alkyl.

3. A compound corresponding in structure to formula (IIIa)

or a pharmaceutically acceptable salt, diastereomer or enantiomer thereof wherein,

R 2 is (C 2 -C 4 )-alkyl, (C 2 -C 4 )-alkenyl, (C 2 -C 4 )-alkinyl, or

R 2 is methyl, which is substituted with a residue selected from cyano, carboxy, methylcarbonyl, (C 3 -C 5 )-cycloalkyl, methoxycarbonyl, monomethylamino, dimethylamino, furanyl, thienyl, imidazolyl, oxazolyl, isoxazolyl, or a heterocyclyl with 3 to 5 ring atoms, or

R 2 is ethyl, which is substituted in one or more places, in the same way or differently, with fluoro, chloro, bromo, cyano, methylcarbonyl, monomethylamino, dimethylamino, —OR 8 , oxiran-2-yl, hydroxyl or a phosphate ester or an ester of an amino acid of said hydroxyl group,

R 2 is propyl or butyl, which is substituted in one or more places, in the same way or differently, with fluoro, chloro, bromo, cyano, methoxy, hydroxyl or a phosphate ester or an ester of an amino acid of said hydroxyl group;

R 3 is methyl, propargyl, butynyl, or cyanomethyl;

Rx is selected from the group consisting of halogen, amino, methyl, and —OR 5 ;

Ry is selected from the group consisting of hydrogen, fluoro, chloro, bromo, methyl and methoxy; or

Rx and Ry together with the carbon atoms to which they are attached form a second heterocyclic 5 or 6-membered ring which contains one or more oxygen atoms thus forming a bicyclic ring system, which can be substituted with one or two residues selected from methoxy, methyl and hydroxyl;

R 5 is methyl or furanylmethyl, or

R 5 is (C 1 -C 4 )-alkyl substituted in one or more places, in the same way or differently, with carboxy, hydroxyl or a phosphate ester thereof, or —NR 6 R 7 ;

R 6 and R 7 are independently hydrogen, (C 1 -C 3 )-alkyl, or form together with the nitrogen atom to which they are attached a five or six membered ring which may contain one or two additional ring forming heteroatoms selected from N and O, and which five or six membered ring may be unsubstituted or may be substituted at the second ring forming nitrogen, if present, with one or more residues selected from (C 1 -C 3 )-alkyl; hydroxyl(C 1 -C 3 )-alkyl; amino(C 1 -C 3 )-alkyl; (C 1 -C 3 )-alkoxy(C 1 -C 3 )-alkyl; halo(C 1 -C 3 )-alkyl; mono(C 1 -C 2 )-alkylamino(C 1 -C 3 )-alkyl; and di(C 1 -C 2 )-alkylamino(C 1 -C 3 )-alkyl; and

R 8 is methyl.

4. A compound corresponding in structure to formula (IIIa)

or a pharmaceutically acceptable salt, diastereomer or enantiomer thereof wherein,

R 2 is (C 2 -C 4 )-alkyl, (C 2 -C 4 )-alkenyl, (C 2 -C 4 )-alkinyl, or

R 2 is methyl, which is substituted with cyano, carboxy, oxiran-2-yl, furan-2-yl, furan-3-yl, thien-2-yl, thien-3-yl, isoxazol-5-yl, imidazol-4-yl, cyclopropyl or methoxycarbonyl; or

R 2 is ethyl, which is substituted in one or more places, in the same way or differently, with fluoro, chloro, bromo, cyano, oxiran-2-yl, mono(C 1 -C 2 )alkyl amino, di(C 1 -C 2 )alkyl amino, hydroxyl or a phosphate ester thereof or

R 2 is propyl, which is substituted in one or more places, in the same way or differently with fluoro, chloro, bromo, cyano, hydroxyl or a phosphate ester thereof

R 2 is butyl, which is substituted in one or more places with hydroxyl or a phosphate ester of said hydroxyl group;

R 3 is methyl, propargyl, butynyl, or cyanomethyl;

Rx is selected from the group consisting of fluoro, chloro, bromo, methyl, methoxy, ethoxy, allyloxy, methoxyethoxy, hydroxyethoxy, mono(C 1 -C 2 )-alkylaminopropoxy, mono(C 1 -C 2 )-alkylaminoethyloxy, di(C 1 -C 2 )-alkylaminopropoxy, di(C 1 -C 2 )-alkylaminoethyloxy, furanylmethyloxy, and carboxymethyloxy;

Ry is selected from the group consisting of hydrogen, methoxy, ethoxy, fluoro, and chloro,

or

Rx and Ry together with the carbon atoms to which they are attached form a second heterocyclic five membered ring which contains one or two ring forming heteroatoms selected among O and N thus forming together with the phenyl ring a bicyclic ring system.

5. A compound according to claim 2 , wherein

R 2 is ethyl, propyl, butyl, allyl, butenyl, propargyl or butynyl, or

R 2 is methyl, which is substituted with a residue selected from cyano, carboxy, methylcarbonyl, methoxycarbonyl, cyclopropyl, furanyl, thienyl, imidazolyl, oxazolyl, isoxazolyl, or oxiranyl, or

R 2 is ethyl, which is substituted in one or two places with fluoro, chloro, bromo, cyano, methylcarbonyl, monomethylamino, dimethylamino, methoxy, ethoxy, hydroxyl or a phosphate ester of said hydroxyl group,

R 2 is propyl, which is substituted in one or two places with fluoro, chloro, bromo, cyano, methoxy, hydroxyl or a phosphate ester of said hydroxyl group, or

R 2 is butyl, which is substituted in one or more places with hydroxyl or is substituted with a phosphate ester of a hydroxyl group.

6. A compound according to claim 3 wherein

R 2 is C 2 -C 4 alkyl, C 3 -C 4 alkenyl, C 3 -C 4 -alkynyl, or

R 2 is methyl, which is substituted with cyano, oxiran-2-yl, furan-2-yl, furan-3-yl, thien-2-yl, thien-3-yl, cyclopropyl, methylcarbonyl, methoxycarbonyl, or

R 2 is ethyl which is substituted with halogen, cyano, methylcarbonyl, or oxiran-2-yl, or

R 2 is propyl or butyl, which is substituted with halogen or cyano; and

Rx is amino or OR 5 , and

Ry is selected from the group consisting of hydrogen, methoxy, and fluoro,

R 5 is C 1 -C 5 -alkyl which is substituted with a hydroxyl group, a phosphate ester of a hydroxyl group, or with NR 6 R 7 ;

R 6 and R 7 are independently hydrogen, (C 1 -C 2 )-alkyl, or form together with the nitrogen atom to which they are attached a five membered ring which may contain one additional ring forming nitrogen atom which nitrogen atom may be further substituted with a residue selected from (C 1 -C 2 )-alkyl; hydroxyl(C 1 -C 3 )-alkyl; amino(C 1 -C 3 )-alkyl; (C 1 -C 2 )-alkoxy(C 1 -C 2 )-alkyl; halo(C 1 -C 2 )-alkyl; mono(C 1 -C 2 )-alkylamino(C 1 -C 2 )-alkyl; and di(C 1 -C 2 )-alkylamino(C 1 -C 2 )-alkyl.

7. A compound according to anyone any one of claims 3 - 6 , wherein

R 2 is methyl, which is substituted with

(i) methylamino, or

(ii) di(C 1 -C 2 )alkylamino; or

R 2 is ethyl, which is substituted with

(iii) one or more —OH groups,

(iv) a phosphate ester of a OH group

(v) methylamino, or

(vi) di(C 1 -C 2 )alkylamino; or

R 2 is propyl or butyl, each of which is substituted with

(i) one or more —OH groups or

(ii) a phosphate ester of a OH group.

8. A compound according to one of claims 3 - 6 , wherein

R 2 is ethyl, propyl, butyl; allyl, butenyl, propargyl, methylcarbonylmethyl, methylcarbonylethyl, methoxycarbonylmethyl, carboxy, cyanomethyl, 2-cyanoethyl, 3-cyanopropyl, 2,3-dihydroxypropyl and the phosphate esters thereof, furan-2-ylmethyl, furan-3-ylmethyl, thien-2-ylmethyl, thien-3-ylmethyl, isoxazol-5-ylmethyl, imidazol-4-ylmethyl, oxiran-2-yl-methyl, 2-methoxyethyl, 2-hydroxyethyl and the phosphate ester thereof, oxiran-2-yl-ethyl, 3-hydroxypropyl and the phosphate ester thereof, 2-hydroxypropyl and the phosphate ester thereof, 3-hydroxy-2-methylpropyl and the phosphate ester thereof, 2,2,2-trifluoroethyl, 3,3,3-trifluoropropyl, cyclopropylmethyl, 2-ethoxyethyl, 2-methoxyethyl, 2-fluoroethyl, 2-bromoethyl, 3-fluoropropyl, 4-fluorobutyl, 3-methoxypropyl, methylaminoethyl, or N,N-dimethylaminoethyl.

9. A compound according to any one of claims 2 , 3 , or 6 , wherein R 2 is ethyl, n-propyl or fluoro(C 2 -C 4 )-alkyl.

10. A compound according to any one of claims 3 - 6 , wherein Rx and Ry are both methoxy.