| abstract |
Compounds of the formula <IMAGE> and pharmaceutically acceptable non-toxic acid addition salts thereof, in which L and D define the chirality; R1 is hydrogen or C1-C3 primary alkyl; R2 is C1-C4 primary or secondary alkyl, allyl, cyclopropylmethyl, C1-C2 hydroxyalkyl, or -(CH2)m-U-CH3 in which U is -S- or >S-O and m is 1 or 2; R3 is hydrogen, C1-C4 primary or secondary alkyl, cyclopropylmethyl, allyl or propargyl; and Z is -CH2OR4, <IMAGE> in which R4 is hydrogen, acetyl, or acetoxymethyl and R5 is C1-C3 alkyl; are useful analgesic agents. |