| abstract |
Opioid peptides including those of formula (I), in which A1 is the identifying group of an amino acid selected from 3,4-dihydroxyphenylalanine, 3,4-dimethoxyphenylalanine, azatyrosine, and 2,6-dimethyltyrosine; A2 is the identifying group of an amino acid selected from D-Ala and D-Arg; A3 is H, or the identifying group of an amino acid selected from 3,4-dihydroxyphenylalanine and 3,4-dimethoxyphenylalanine, A4 is H, cyclohexylmethyl, the identifying group of an amino acid selected from 3,4-dihydroxyphenylalanine, 3,4-dimethoxyphenylalanine, Phe, and substituted Phe with its benzene ring substituted by halogen, NO2, OH, or CH3; A5 is the identifying group of a D- or L-amino acid selected from Leu, Nle, Lys, Met and Met(O), or is deleted together with R4-CH attached thereto; each R1 and R2 is -H, -C(NH2) = NH, or C1-12 alkyl; R3 is -(a) or (b); R4 is (c); (d), or (e); and R5 is -(CH2)n+1OH, (f), or (g); wherein m is 0-6, n is 0-6, and X is H, C1-12 alkyl, C6-12 aryl, C7-18 aralkyl, C7-18 alkaryl, C7-18 alkaryl, C6-17 pyridylalkyl, or C6-17 alkylpyridyl; provided that when one of R1 and R2 is -C(NH2) = NH, the other must be H; or a pharmaceutically acceptable salt thereof. |