Pharmaceutical compounds

PCT No. PCT/GB95/00302 Sec. 371 Date Sep. 25, 1996 Sec. 102(e) Date Sep. 25, 1996 PCT Filed Feb. 14, 1995 PCT Pub. No. WO95/21832 PCT Pub. Date Aug. 17, 1995Diketopiperazines of the formula ifferent, are chosen from X and a phenyl group substituted by X, C(O)X, OC(O)CH2X, OCH2CH2X, CH2X, CONH(CH2)nX, O(CH2)nCH(OH)(CH2)nX and, where appropriate, the other of R1 and R2 is a phenyl group optionally substituted by one or more groups selected from halogen, nitro, methoxy, NHC(O)R12, CO2H, O(CH2)nN(R12R13), C1-C4 alkyl and (CH2)nC(O)OR12; X is a five- or six-membered heterocyclic ring selected from the group consisting of pyridyl, imidazolyl, furyl, pyrrolyl, pyrrolidinyl, thienyl, piperazinyl, piperidinyl, morpholinyl, quinolyl, isoquinotyl and indolyl, the heteroatom(s) of the said heterocyclic ring, when nitrogen, being optionally substituted by hydrogen, methyl, oxygen, tertiary-butyloxycarbonyl, or SO2Me, the heterocyclic ring being optionally substituted by halogen [hydrogen], methyl, MeS, phenyl, O(CH2)nN(R12R13) or optionally containing one or more carbonyl groups and being optionally fused to a benzene ring; Y is O or S; R12 and R13, which may be the same or different, are hydrogen or C1-C6 alkyl; and n is 0 or an integer having the value 1, 2, 3 or 4; a pharmaceutically acceptable salts or esters having activity as inhibitors of plasminogen activator inhibitor.