Amino acid derivatives possessing prolyl endopeptidase-inhibitory activities

摘要

Amino acid derivatives of the formula ##STR1## wherein: Q is W- -(CH. sub.2).sub.m --(A).sub.n --CO--B-- whereinPPA is oxygen atom or --NH--;PPB is ##STR2## or --(CH.sub.2).sub. l -- wherein X is sulfur atom or --CH.sub.2 --, and l is an integer from 1 to 3;PPW is ##STR3## wherein Hal is halogen atom; n is an integer of 0 or 1; andPPm is an integer from 0 to 3; PPY is sulfur atom or --CH.sub.2 --; andP PR is hydrogen atom, formyl group, C.sub.1-5 alkoxycarbonyl group, -- C.tbd.N or ##STR4## wherein R.sup.1 is hydrogen atom, andP PR.sup. 2 is hydroxyl group, C.sub.1-5 alkylcarboxy group, phenylcarboxy group, C. sub.1-5 alkoxy group or phenyl C.sub.1-5 alkoxy group;PP with the proviso that when R is hydrogen atom, formyl group or C.sub.1-5 alkoxycarbonyl group, W is ##STR5## The compounds mentioned above specifically inhibit prolyl endopeptidase activity and are useful as agents for the treatment and prevention of dementia and amnesia.