Pharmacologically active peptides

Abstract

Compounds of the formula ##STR1## and pharmaceutically acceptable non-toxic acid addition salts thereof, in which L and D define the chirality; R.sub.1 and R.sub.2 independently are hydrogen or C.sub.1 -C.sub.3 primary alkyl; R.sub.3 is C.sub.1 -C.sub.4 primary or secondary alkyl, C.sub.1 -C.sub.2 hydroxyalkyl, or --CH.sub.2 CH.sub.2 --U--CH.sub.3, in which U is O or S; R.sub.4 is C.sub.1 -C.sub.3 primary alkyl; Y is hydrogen or acetyl; Z is --CH.sub.2 OH or ##STR2## in which R.sub.5 is C.sub.1 -C.sub.3 alkyl or hydrogen; and W is isopropyl, --VR.sub.6, or --CH.sub.2 --X--CH.sub.3, in which V is O or S, R.sub.6 is C.sub.1 -C.sub.4 alkyl or aralkyl, and X is O, S, or CH.sub.2 --; are useful analgesic agents.