Efficient protocol to quinazolino[3,2-d][1,4]benzodiazepine-6,9-dione via Staudinger-aza-Wittig cyclization: Application to synthesis of Asperlicin D

Abstract

Tandem Staudinger and intramolecular aza-Wittig reactions followed by cyclodehydration of the linear N-[N-(2-azidobenzoyl)-2-aminobenzoyl]glycine ethyl ester furnished the tetracyclic quinazolino[3,2-d][1,4]benzodiazepine-6,9- dione ring system found in some biologically active natural alkaloids. This method was successfully implemented to synthesize asperlicin D from a linear peptide containing ester and azido terminal groups. © ARKAT USA, Inc.