Novel peptide derivatives and their pharmaceutical use.

摘要

Peptide derivatives of the following general formula <CHEM> wherein R<1> and R<2> are the same or different and respectively mean a hydrogen atom or a C1-5 alkyl group, R<3> and R<4> are the same or different and respectively mean a hydrogen atom or a C1-5 alkyl or phenyl, or R<3> and R<4> combinedly mean a C2-7 alkylene group, R<5> and R<6> are the same or different and respectively mean a hydrogen atom or a C1-5 alkyl group, X means -NH-, -O- or -CH2-, Y means -CH2- or -S-, and m and n respectively mean 0 or 1, provided that when X is -NH- or -O-, m is 1 and all of R<1>, R<2>, R<3> and R<4> do not mean a hydrogen atom at the same time; acid addition salts thereof; and pharmaceutical use thereof. Since the compounds and their acid addition salts of the present invention possess more potent actions on central nervous system (e.g. antagonistic action against hypothermia, locomotor stimulant action, spinal reflex stimulant action), they are of use as a therapeutic medicament for central nervous disorders such as impaired consciousness, depression, hypomnesia, the like in association with schizophrenia, melancholia, senile dementia, sequelae of cerebrovascular disorders, head trauma, epilepsy and spinocerebellar degeneracy.