| abstract |
Compounds of the formula wherein R is a hydrogen atom or an acyl; U is -O-, -CHR1- or -NR2- wherein R1 is a hydrogen atom or a hetero ring, and R2 is a hydrogen atom or a lower alkoxycarbonyl lower alkyl; V is -O-, -S-, -CHR3- or -NR4- wherein R3 is a hydrogen atom or a lower alkoxycarbonyl, and R4 is a hydrogen atom, a lower alkyl or an acyl; W is methyl, a hetero ring or optionally substituted phenyl; X and Y are the same or different and each is -CH2- or -S-; m is an integer of 0 to 6; and n is an integer of 1 to 4, and pharmaceutically acceptable salts thereof. The compounds of the present invention have specifically strong inhibitory activity against prolyl endopeptidase, and suppress decomposition and inactivation of TRH, substance P, neurotensin, vasopressin and the like. Accordingly, the compounds can be used for the prophylaxis and/or treatment of dementia and amnesia including Alzheimer's disease. |