A compound of general formula (I') wherein R1 is (CH 2) n -Z-(CH 2) n' -R4 wherein n and n' are each independently 0, 1 or 2; Z is a single bond or is selected from the group consisting of S, O, CO and NR3, wherein R3 is selected from the group consisting of H, straight or branched (C 1 -C 6)alkyl, (C 1 -C 6)haloalkyl, (C 3 -C 8)cycloalkyl, aryl, aryl(C 1 -C 6)alkyl and heteroaryl, which are optionally substituted by CN; R4 is selected from the group consisting of: - H, halogen, OH, SH, CN, NH 2; - aryl(C 1 -C 6)alkyl, (C 1 -C 6)alkylsulfonyl, (C 1 -C 6)alkylcarbonyl, (C 1 -C 6)alkylcarboxyl, O(C 1 -C 6)alkylcarboxyl, (C 1 -C 6)alkylamide and (C 1 -C 6)alkoxy, which are optionally substituted by oxo groups; - (C 1 -C 6)alkyl which may be optionally substituted by one or more substituents selected from the group consisting of halogen atoms, CN, OH, NH 2, NO 2, CF 3 and SH; - (C 2 -C 6)alkynyl; - a mono-, bi- or tricyclic saturated or partially saturated or unsaturated ring, such as (C 3 -C 8)cycloalkyl, aryl, (C 5 -C 10)heterocycloalkyl or heteroaryl, optionally substituted by one or more halogen atoms or oxo groups; R2 is the group - (CH 2) p R8 wherein R8 is selected from the group consisting of halogen, oxo, CN, OH, NH 2, NO 2; (C 3 -C 8)cycloalkyl, aryl and a saturated, partially saturated or unsaturated optionally fused ring such as (C 5 -C 10)heterocycloalkyl, which are optionally substituted by one or more substituents selected from the group consisting of halogen, CO, CN, (C 1 -C 6)alkyl, (C 1 -C 6)haloalkyl, (C 1 -C 6)carboxyalkyl, (C 1 -C 6)alkoxy, (C 1 -C 6)haloalkoxy and (C 1 -C 6)alkylsulfonyl; wherein p is 0 or an integer from 1 to 6 and and X and Y are both fluorine atoms And wherein 4a is, 4b is, 5 is, 6a is, 6b is, 9a is, 10a is, 10b is and 12 is and pharmaceutically acceptable salts thereof. wherein R1 is (CH 2) n -Z-(CH 2) n' -R4 wherein n and n' are each independently 0, 1 or 2; Z is a single bond or is selected from the group consisting of S, O, CO and NR3, wherein R3 is selected from the group consisting of H, straight or branched (C 1 -C 6)alkyl, (C 1 -C 6)haloalkyl, (C 3 -C 8)cycloalkyl, aryl, aryl(C 1 -C 6)alkyl and heteroaryl, which are optionally substituted by CN; R4 is selected from the group consisting of: - H, halogen, OH, SH, CN, NH 2; - aryl(C 1 -C 6)alkyl, (C 1 -C 6)alkylsulfonyl, (C 1 -C 6)alkylcarbonyl, (C 1 -C 6)alkylcarboxyl, O(C 1 -C 6)alkylcarboxyl, (C 1 -C 6)alkylamide and (C 1 -C 6)alkoxy, which are optionally substituted by oxo groups; - (C 1 -C 6)alkyl which may be optionally substituted by one or more substituents selected from the group consisting of halogen atoms, CN, OH, NH 2, NO 2, CF 3 and SH; - (C 2 -C 6)alkynyl; - a mono-, bi- or tricyclic saturated or partially saturated or unsaturated ring, such as (C 3 -C 8)cycloalkyl, aryl, (C 5 -C 10)heterocycloalkyl or heteroaryl, optionally substituted by one or more halogen atoms or oxo groups; - H, halogen, OH, SH, CN, NH 2; - aryl(C 1 -C 6)alkyl, (C 1 -C 6)alkylsulfonyl, (C 1 -C 6)alkylcarbonyl, (C 1 -C 6)alkylcarboxyl, O(C 1 -C 6)alkylcarboxyl, (C 1 -C 6)alkylamide and (C 1 -C 6)alkoxy, which are optionally substituted by oxo groups; - (C 1 -C 6)alkyl which may be optionally substituted by one or more substituents selected from the group consisting of halogen atoms, CN, OH, NH 2, NO 2, CF 3 and SH; - (C 2 -C 6)alkynyl; - a mono-, bi- or tricyclic saturated or partially saturated or unsaturated ring, such as (C 3 -C 8)cycloalkyl, aryl, (C 5 -C 10)heterocycloalkyl or heteroaryl, optionally substituted by one or more halogen atoms or oxo groups; R2 is the group - (CH 2) p R8 wherein R8 is selected from the group consisting of halogen, oxo, CN, OH, NH 2, NO 2; (C 3 -C 8)cycloalkyl, aryl and a saturated, partially saturated or unsaturated optionally fused ring such as (C 5 -C 10)heterocycloalkyl, which are optionally substituted by one or more substituents selected from the group consisting of halogen, CO, CN, (C 1 -C 6)alkyl, (C 1 -C 6)haloalkyl, (C 1 -C 6)carboxyalkyl, (C 1 -C 6)alkoxy, (C 1 -C 6)haloalkoxy and (C 1 -C 6)alkylsulfonyl; - (CH 2) p R8 wherein R8 is selected from the group consisting of halogen, oxo, CN, OH, NH 2, NO 2; (C 3 -C 8)cycloalkyl, aryl and a saturated, partially saturated or unsaturated optionally fused ring such as (C 5 -C 10)heterocycloalkyl, which are optionally substituted by one or more substituents selected from the group consisting of halogen, CO, CN, (C 1 -C 6)alkyl, (C 1 -C 6)haloalkyl, (C 1 -C 6)carboxyalkyl, (C 1 -C 6)alkoxy, (C 1 -C 6)haloalkoxy and (C 1 -C 6)alkylsulfonyl; wherein p is 0 or an integer from 1 to 6 and and X and Y are both fluorine atoms And wherein 4a is, 4b is, 5 is, 6a is, 6b is, 9a is, 10a is, 10b is and 12 is and pharmaceutically acceptable salts thereof.