6,8-Disubstituted-9-(heterocyclyl)purines of general formula I wherein Cyc is heterocyclyl selected from the group consisting of 2-tetrahydropyranyl and 2-tetrahydrofuranyl; R6 is -NH-R y, R y is selected from the group consisting of: - C 1 to C 8 linear or branched alkyl, optionally substituted by at least one substituent selected from the group consisting of hydroxy, halogen, C 1 to C 4 alkoxy, - C 2 to C 8 linear or branched alkenyl, optionally substituted by at least one substituent selected from the group consisting of hydroxy, halogen, C 1 to C 4 alkoxy, - C 3 to C 8 cycloalkyl, optionally substituted by at least one substituent selected from the group consisting of hydroxy, halogen, C 1 to C 4 alkyl, C 1 to C 4 alkoxy, - benzyl, optionally substituted by at least one substituent selected from the group consisting of hydroxy, halogen, C 1 to C 4 alkyl, C 1 to C 4 alkoxy, amino, nitro, - phenyl, optionally substituted by at least one substituent selected from the group consisting of hydroxy, halogen, C 1 to C 4 alkyl, C 1 to C 4 alkoxy, amino, nitro, - furfuryl, optionally substituted by at least one substituent selected from the group consisting of hydroxy, halogen, C 1 to C 4 alkyl, C 1 to C 4 alkoxy, amino, nitro, and R8 is selected from the group comprising amino, hydroxy, fluorine, bromine, chlorine, acyl, acyloxy, amido, alkoxy, benzyloxy, alkylamino, dialkylamino, alkenylamino, carbamoyl, carboxyl, cyano, hydrazino, -NHOH, NHNH 2, -NHCONH 2, -NH-C NH 2, nitro, sulphanyl, alkylsulphanyl, sulpho, and alkyloxycarbonyl, whereas alkylamino denotes the group -N(R e) 2, wherein each R e is independently selected from hydrogen, alkyl, and alkenyl, each of which can be substituted by amino or hydroxyl substituent. Cyc is heterocyclyl selected from the group consisting of 2-tetrahydropyranyl and 2-tetrahydrofuranyl; R6 is -NH-R y, R y is selected from the group consisting of: - C 1 to C 8 linear or branched alkyl, optionally substituted by at least one substituent selected from the group consisting of hydroxy, halogen, C 1 to C 4 alkoxy, - C 2 to C 8 linear or branched alkenyl, optionally substituted by at least one substituent selected from the group consisting of hydroxy, halogen, C 1 to C 4 alkoxy, - C 3 to C 8 cycloalkyl, optionally substituted by at least one substituent selected from the group consisting of hydroxy, halogen, C 1 to C 4 alkyl, C 1 to C 4 alkoxy, - benzyl, optionally substituted by at least one substituent selected from the group consisting of hydroxy, halogen, C 1 to C 4 alkyl, C 1 to C 4 alkoxy, amino, nitro, - phenyl, optionally substituted by at least one substituent selected from the group consisting of hydroxy, halogen, C 1 to C 4 alkyl, C 1 to C 4 alkoxy, amino, nitro, - furfuryl, optionally substituted by at least one substituent selected from the group consisting of hydroxy, halogen, C 1 to C 4 alkyl, C 1 to C 4 alkoxy, amino, nitro, and - C 1 to C 8 linear or branched alkyl, optionally substituted by at least one substituent selected from the group consisting of hydroxy, halogen, C 1 to C 4 alkoxy, - C 2 to C 8 linear or branched alkenyl, optionally substituted by at least one substituent selected from the group consisting of hydroxy, halogen, C 1 to C 4 alkoxy, - C 3 to C 8 cycloalkyl, optionally substituted by at least one substituent selected from the group consisting of hydroxy, halogen, C 1 to C 4 alkyl, C 1 to C 4 alkoxy, - benzyl, optionally substituted by at least one substituent selected from the group consisting of hydroxy, halogen, C 1 to C 4 alkyl, C 1 to C 4 alkoxy, amino, nitro, - phenyl, optionally substituted by at least one substituent selected from the group consisting of hydroxy, halogen, C 1 to C 4 alkyl, C 1 to C 4 alkoxy, amino, nitro, - furfuryl, optionally substituted by at least one substituent selected from the group consisting of hydroxy, halogen, C 1 to C 4 alkyl, C 1 to C 4 alkoxy, amino, nitro, R8 is selected from the group comprising amino, hydroxy, fluorine, bromine, chlorine, acyl, acyloxy, amido, alkoxy, benzyloxy, alkylamino, dialkylamino, alkenylamino, carbamoyl, carboxyl, cyano, hydrazino, -NHOH, NHNH 2, -NHCONH 2, -NH-C NH 2, nitro, sulphanyl, alkylsulphanyl, sulpho, and alkyloxycarbonyl, whereas alkylamino denotes the group -N(R e) 2, wherein each R e is independently selected from hydrogen, alkyl, and alkenyl, each of which can be substituted by amino or hydroxyl substituent.