Novel thiophene derivatives, their process of preparation and the pharmaceutical compositions which comprise them

A compound of formula (I) selected from: wherein: X represents oxygen or sulphur, Y represents oxygen, -NH- or -N(C1-C6)alkyl-, Ra represents hydrogen, halogen, (C1-C3)alkyl, hydroxyl or (C1-C3)alkoxy, Rb represents hydrogen, halogen or (C1-C3)alkyl, A represents phenyl, pyridyl, (C5-C6)cycloalkyl or (C5-C6)cycloalkenyl, R1 and R2 each represent a group selected from hydrogen, halogen, cyano, nitro, haloalkyl, haloalkoxy, alkyl, alkenyl, alkynyl, -OR4, -NR4R5, -S(O)nR4, -C(O)R4, -CO2R4, -O-C(O)R4, -C(O)NR4R5, -NR5-C(O)R4, -NR5-SO2R4, -T-CN, -T-OR4, -T-OCF3, -T- NR4R5, -T-S(O)nR4, -T-C(O)R4, -T-CO2R4, -T-O-C(O)R4, -T-C(O)NR4R5, -T-NR4-C(O)R5, -T-NR4-SO2R5, -R6 and -T-R6 in which n, T, R4, R5 and R6 are as defined in the description, R3 represents an -R7 or -U-R11 group in which R7 represents hydrogen, alkyl, aryl, cycloalkyl or heterocycle, U represents a linear or branched alkylene chain and R11 is defined in the description, their optical isomers or their addition salts with a pharmaceutically acceptable acid or base, and their use as inhibitor of metalloproteinase and more specifically of metalloproteinase-12.