DIRECT CLEAVAGE OF PEPTIDES FROM A SOLID SUPPORT INTO AQUEOUS BUFFER - APPLICATION IN SIMULTANEOUS MULTIPLE PEPTIDE-SYNTHESIS

A method of simultaneous multiple peptide synthesis which integrates synthesis, side-chain deprotection, cleavage, and purification so as to afford peptide solutions suitable for immediate biological testing is described. The approach utilizes a novel diketopiperazine-forming cleavable linker 1. Upon side-chain deprotection, 1 gives 2, which is stable to a protocol designed to remove contaminants from the support-bound peptide prior to cleavage. Peptide cleavage is then effected by treating 2 with a neutral or near neutral buffer to give peptide 4, which carries a C-terminal diketopiperazine moiety, in good yield. In this study the glycolamido and 4-(oxymethyl)benzamido esters of 1 have been appraised. The approach is demonstrated in model studies on 7 and 8 and in the preparation and characterization of peptides 17-21. The general approach allows 10-100-nmol quantities of many hundreds of peptides to be concurrently prepared in a relatively short period of time when used in conjunction with the multipin method of multiple peptide synthesis.