| abstract |
Peptide derivatives of the following general formula wherein R1 and R2 are the same or different and respectively mean a hydrogen atom or a C1-5 alkyl group, R3 and R4 are the same or different and respectively mean a hydrogen atom or a C1-5 alkyl or phenyl, or R3 and R4 combinedly mean a C2-7 alkylene group, R5 and R6 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 R1, R2, R3 and R4 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. |