Abstract: The present invention relates to a compound of formula (I) in which R1 and R2 independently represent phenyl, thienyl or pyridyl each of which is optionally substituted by one, two or three groups represented by Z; and R3 is H, a C1-3alkyl group, a C1-3alkoxymethyl group, trifluoromethyl, a hydroxyC1-3alkyl group, an aminoC1-3alkyl group, C1-3alkoxycarbonyl, carboxy, cyano, carbamoyl, mono or di C1-3alkylcarbamoyl, acetyl, or hydrazinocarbonyl of formula —CONHNRaRb wherein Ra and Rb are as defined for R4 and R5 respectively; X is CO or SO2; Y is absent or represents NH optionally substituted by a C1-3alkyl group; R4 and R5 independently represent: a C1-6alkyl group; an (amino)C1-4alkyl-group in which the amino is optionally substituted by one or more C1-3alkyl groups; an optionally substituted non-aromatic C3-15carbocyclic group; a (C3-12cycloalkyl)C1-3alkyl-group; a group —(CH2)r(phenyl)s; naphthyl; anthracenyl; a saturated 5 to 8 membered heterocyclic group containing one nitrogen and optionally one of the