Pharmaceutically active compounds

A compound of formula I:

• or pharmaceutically or veterinarily acceptable salts, solvates, polymorphs or pro-drugs thereof wherein:
• A represents C(O) or CH(OH);
• X represents O or NR5;
• R1, R3, R4 and R5 independently represent H, C1-C6 alkyl, Het, C1-C6 alkylHet, aryl or C1-C6 alkylaryl (which latter five groups may all be optionally substituted and/or terminated with one or more substituents selected from halo, cyano, nitro, OR6, OC(O)R6, C(O)R8, C(O)OR6, NR6C(O)NR7R8, NR6C(O)OR8, OC(O)NR7R8, C(O)NR9R10, NR9R10, SO2NR9R10, SO2R11, C1-C6alkyl, Het, C1-C6 alkytHet, aryl or C1-C6 alkylaryl wherein said latter five substituent and/or terminal groups are all optionally substituted and/or terminated with one or more substituents selected from halo, cyano, nitro, OR12, OC(O)R12, C(O)R12, C(O)OR12, NR12C(O)NR13R14, NR12C(O)OR12, OC(O)NR13R14, C(O)NR15R16, NR15R16, SO2NR15R16, SO2R17);
• or when X represents NR5 then R3 and R5 together with the nitrogen atom to which they are bound can form a heterocyclic ring which is optionally substituted and/or terminated with one or more substituents selected from halo, cyano, nitro, OR12, OC(O)R12, C(O)R12, C(O)OR12, NR12C(O)NR13R14, NR12C(O)OR12, OC(O)NR13R14, C(O)NR15R16, NR15R16, SO2NR15R16, SO2R17;
• R2 represents H, halo, cyano, nitro, OR6, OO(O)R6, C(O)RC(O)OR6, NR6C(O)NR7R8, NR6C(O)OR, OO(O)NR7R8, C(O)NR9R10, NR9R10, SO2NR9R10, SO2R11, C1-C6 alkyl, Het, C1-C6 alkylHet, aryl or C1-C6 alkylaryl (which latter five groups may all be optionally substituted and/or terminated with one or more substituents selected from halo, cyano, nitro, OR6, OC(O)R6, C(O)R6, C(O)OR6, NR6C(O)NR7R, NR6C(O)OR6, OC(O)NR7R8, C(O)NR9R10, NR9R10, SO2NR9R10, SO2R1′, C,-06 alkyl, Het, C1-C6 alkylHet, aryl or C1-C6 alkylaryl wherein said latter five substituent and/or terminal groups are all optionally substituted and/or terminated with one or more substituents selected from halo, cyano, nitro, OR12, OC(O)R12, C(O)R12, C(O)OR12, NR12C(O)NR13R14, NR12C(O)OR12, OC(O)NR13R14, C(O)NR15R16, NR15R16, SO2NR15R16, SO2R17);
• R6 represents H, C1-C6 alkyl, Het, C,-Ce alkyiHet, aryl or 01-06 alkylaryl (which latter five groups are all optionally substituted and/or terminated with one or more substituents selected from halo, cyano, nitro, OR12, OC(O)R12, C(O)R12, C(O)OR12, NR12C(O)NR13R14, NR12C(O)OR12, OC(O)NR13R14, C(O)NR15R16, NR15R16, SO2NR15R16, SO2R17);
• R7 and R8 independently represent H, C1-C6 alkyl, Het, C1-C6 alkylHet, aryl or C1-C6 alkylaryl (which latter five groups are all optionally substituted and/or terminated with one or more substituents selected from halo, cyano, nitro, OR12, OC(O)R12, C(O)R12, C(O)OR12, NR12C(O)NR13R14, NR12C(O)OR12, OC(O)NR13R14, C(O)NR15R16, NR15R16, SO2NR15R16, SO2R17);
• or R7 and R8 together with the nitrogen atom to which they are bound can form a heterocyclic ring;
• R9 and R10 independently represent H, C(O)R6, SO2R11, C1-C6 alkyl, Het, C1-C6 alkylHet, aryl or C1-C6 alkylaryl (which latter five groups are all optionally substituted and/or terminated with one or more substituents selected from halo, cyano, nitro, OR12, OC(O)R12, C(O)R12, C(O)OR12, NR12C(O)NR13R14, NR12C(O)OR12, OC(O)NR13R14, C(O)NR15R16, NR15R16, SO2NR15R16, SO2R17);
• or R9 and R10 together with the nitrogen atom to which they are bound can form a heterocyclic ring;
• wherein when R7 and R8, or R9 and R10 together with the nitrogen atom to which they are bound form a heterocyclic ring, said heterocyclic ring is optionally substituted and/or terminated with one or more substituents selected from:
• halo, cyano, nitro, OR12, OC(O)R12, C(O)R12, C(O)OR12, NR12C(O)NR13R14, NR12C(O)OR12, OC(O)NR13R14, C(O)NR15R16, NR15R16, SO2NR15R16, SO2R17;
• R11 represents a C1-C6 alkyl, Het, C1-C6 alkylHet, aryl or C1-C6 alkylaryl group is optionally substituted and/or terminated with one or more substituents selected from halo, cyano, nitro, OR12, OC(O)R12, C(O)R12, C(O)OR12, NR12C(O)NR13R14, NR12C(O)OR12, OC(O)NR13R14, C(O)NR15R18, NR15R16, SO2NR15R16, SO2R17;
• R12 represents H or C1-C6 alkyl;
• R13 and R14 independently represent H or C1-C6 alkyl;
• or R13 and R14 together with the nitrogen atom to which they are bound can form a heterocyclic ring;
• R15 and R16 independently represent H, C(O)R12, SO2R17 or C1-C6 alkyl;
• or R15 and R16 together with the nitrogen atom to which they are bound can form a heterocyclic ring;
• R17 represents C1-C6 alkyl;
• Het represents an optionally substituted four- to twelve-membered heterocyclic group, which group contains one or more heteroatoms selected from nitrogen, oxygen, sulpur and mixtures thereof;
• with the proviso that when X represents O and R1 represents H, C3-C1 alkyl optionally substituted with fluoro or C3-C5 cycloalkyl then
• R2 does not represent H, C1-C 6 alkyl optionally substituted with one or more fluoro substituents or with C3-C6 cycloalkyl;
• or
• R3 does not represent C1-C6 alkyl optionally substituted with one or morfluoro substituents or with C3-C6 cycloalkyl;
• C3-C5 cycloalkyl;
• C3-C6 alkenyl;
• or C3-C6 alkynyl;
• or
• R4 does not represent C1-C4 alkyl optionally substituted with OH, NR9R10, CN, CONR9R10, SO2NR9R10 or CO2R6 wherein R6 is H or C1-C4 alkyl and R9 and R10 are each independently H or C1-C4 alkyl, or together with the nitrogen atom to which they are attached form a pyrrolidinyl, piperidino, morpholino, 4-substituted piperizinyl or imidazolyl group wherein said group is optionally substituted with C1-C4 alkyl or OH;
• C2-C4 alkenyl optionally substituted with CN, CONR9R10 or CO2R6;
• C2-C4 alkanoyl optionally substituted with NR9R10;
• (C2-C4)OH optionally substitued with NR9R10;
• (C2-C3)alkoxy(C1-C2)alkyl optionally substituted with OH or NR9R10.