Novel derivatives of beta-endorphin, intermediates therefor and compositions and methods employing said derivatives

A hentriacosapeptide of the formula

• R.sub.1 -Tyr(R.sub.2)-X(Z)--Gly-Phe-Met-Thr(R.sub.3)-Ser(R.sub.3)-Glu(R.sub.4)-Lys (R.sub.5)-Ser(R.sub.3)-Gln-Thr(R.sub.3)-Pro-Leu-Val-Thr(R.sub.3)-Leu-Phe-Ly s(R.sub.5)-Asn-Ala-Ile-Ile-Lys(R.sub.5)-Asn-Ala-Tyr(R.sub.2)-Lys(R.sub.5)-L ys(R.sub.5)-Gly-Gln(R.sub.4)-Y
• wherein X is a chiral residue of a D-amino acid selected from the group consisting of D-leucine and D-lysine;
• Z is a protecting group for the chiral residue, M is an integer from zero to one, being one when X is D-lysine and being zero for any other residue;
• R.sub.1 is a N-terminus solid phase peptide synthesis protecting group selected from the group consisting of acyl type protecting groups, aromatic urethan-type protecting groups, alkyl type protecting groups, trialkylsilane groups, or aliphatic urethan protecting groups;
• R.sub.2 is a protecting group for the phenolic hydroxyl group of tyrosine selected from the group consisting of tetrahydropyranyl, tert-butyl, trityl, benzyl, 2,4-dichlorobenzyl, benzyloxycarbonyl and 2-bromobenzyloxycarbonyl;
• R.sub.3 is a protecting group for the alcohol hydroxy functions of serine and threonine;
• R.sub.4 is a protecting group for the gamma carboxyl group of glutamic acid;
• R.sub.5 is a protecting group for the epsilon amino group of lysine selected from the group consisting of trifluoraacetyl, benzyloxycarbonyl, and 2-chlorobenzyloxycarbonyl;
• and
• Y is selected from the group consisting of hydroxy, amino, loweralkylamino, diloweralkylamino, and lower alkoxy;
• or a derivatized insoluble polystyrene resin support represented by the formulas ##STR2##