Pharmaceutical compounds

PCT No. PCT/GB93/01734 Sec. 371 Date Apr. 11, 1995 Sec. 102(e) Date Apr. 11, 1995 PCT Filed Aug. 16, 1993 PCT Pub. No. WO94/04512 PCT Pub. Date Mar. 3, 1994Diketopiperazines of the formula: ame or different, is independently selected from the group consisting of hydrogen, C1-C6 alkyl unsubstituted or substituted by one or more halogen atoms, C1-C6 alkoxy, C1-C6 alkylthio, halogen, hydroxy, nitro, phenyl, -cyano, -CH2OH, -CH2COOH, -CO2R11, -NHCOR11, -NHSO2R13, -SO2R13, -CON(R11R12), -SOR13, -SO2N(R11R12), -N(R11R12), and -O(CH2)nN(R11R12), -O(CH2)nCO2R11, -OCOR11, -CH2OCOR11, -CH2NHCOR11, -CH2NHCOOR13, -CH2SR11, -CH2SCOR11, -CH2S(O)mR13 wherein m is 1 or 2, -CH2NHCO(CH2)nCO2R11, -N(R11)COR12, -NHCOCF3, -NHCO(CH2)nCO2R11, -NHCO(CH2)nOCOR11 and -NHCO(CH2)nOR11 wherein n is 0 or is an integer of from 1 to 6, each of R11 and R12 is independently H or C1-C6 alkyl and R13 is C1-C6 alkyl; or any of R1 and R2, R2 and R3, R3 and R4 and R4 and R5, or R6 and R7, R7 and R8, R8 and R9 and R9 and R10, form together with the carbon atoms to which they are attached a benzene ring; and pharmaceutically acceptable salts and esters thereof are inhibitors of the plasminogen activator inhibitor.