| 摘要 |
NEW MATERIAL:The titled compound of formula I (R<1> is lower alkyl; X is Ala, Ser, etc.), and a salt thereof. EXAMPLE:N-Methyl-L-tyrosyl-D-alanyl-glycyl-L-phenylalanyl-L-methioninol. USE:Useful as an analgesic, a narcotic antagonistic and an antidiarrheic drugs having an agonistic activity in the opiate acceptor and a prolonged duration with low toxicity, and including any of optical isomers and racemates. PROCESS:An enkephalin derivative of formula II (R<2> is alkoxycarbonyl etc.; R<3> is lower alkyl etc.) is reacted with at least one type of acid selected from the group consisting of methanesulfonic acid etc. as a deprotection agent and a thioether derivative of formula III (R<4> is lower alkyl) in the presence or absence of a solvent to give the titled compound of formula I. |
