An alternative approach towards novel heterocycle-fused 1,4-diazepin-2-ones by an aromatic amidation protocol

The synthesis of new 1,4-diazepin-2-one derivatives starting from glycine or alanine aminoacids is presented. The key cyclization step includes the PIFA mediated formation of N-acylnitrenium ions and their subsequent intramolecular trapping by an (hetero)aromatic ring. The so-promoted aromatic amidation process takes place without loss of enantiomeric purity when optically pure methoxyamide precursors are employed. (C) 2003 Elsevier Ltd. All rights reserved.