Synthesis and conformation of n-trityl dipeptide derivatives

Abstract

N-Tritylamino acids activated with DCC/HOBt, were coupled with various amino acid derivatives without racemization. The trityl group was split off quantitatively in 10% CCl 3COOH monohydrate or CH 2ClCOOH in CH 2Cl 2. Under these conditions detritylation of N-Trt-Trp-Gly-NH 2 proceeds without formation of an oxindole derivative and side alkylation products, even in the absence of a scavenger. Dipeptide derivatives 1 and 2 exhibited magnetic asymmetry, attributed to steric factors.