A compound of general formula (I), ** Formula ** in which R 1 represents hydrogen, (C 1 -C 10) alkyl, (C 2 -C 10) alkenyl, (C 2 -C 10) alkynyl, C (C 3 -C 8) alkynyl groups, (C5-C8) cycloalkenyl, aryl, heteroaryl, heterocyclyl, aralkyl, cycloalkanylalkyl, heteroaralkyl, optionally substituted heterocyclylalkyl； R2 represents hydrogen, optionally substituted alkyl, cycloalkyl, aryl, heteroaryl, heterocyclyl and acyl groups； R3 and R4 each independently represent hydrogen, optionally substituted alkyl, cycloalkyl, aryl, heterocyclyl, heteroaryl groups； or R3 and R4 together with the carbon atom to which they are attached form a cycloalkyl group, or heterocyclyl in which the heterocyclyl group may also contain one or more heteroatoms selected from O, N &S； R5 is selected from the group comprising -OR6, -COOR6, -NR7COR6 and -NR7SO2R6 in which each of R6 and R7 at each occurrence are independently selected from the group comprising hydrogen, optionally substituted groups selected from alkyl, cycloalkyl, aryl, heterocyclyl and heteroaryl； "A" represents a saturated or unsaturated 5-7 membered carbocyclic or heterocyclic ring system in which the heterocyclic ring also contains one or more heteroatoms selected from N, O or S (O) m； said cycle representing "A" is further substituted by one or more substituents selected from the group of substituents represented by R8s； wherein R8 is selected from the group consisting of hydrogen, hydroxy, cyano, halo, (C1-C10) alkyl, -COR9, -OR9, -S (O) mR9, -SO2NR9R10, -N (R9) SO2R10 in the that each of R9 and R10 at each occurrence independently represents hydrogen, optionally substituted (C1-C10) alkyl, or aryl； "m" represents whole numbers of 0-2 and "n" represents whole numbers of 1-4.Un compuesto de fórmula general (I),**Fórmula** en la que R1 representa hidrógeno, grupos alquilo (C1-C10), alquenilo (C2-C10), alquinilo (C2-C10), cicloalquilo (C3-C8), cicloalquenilo (C5-C8), arilo, heteroarilo, heterociclilo, aralquilo, cicloalcanilalqui
