摘要:
Chemo-selective reduction of the pyroglutamate ring carbonyl in a serine-pyroglutamate or homoserine to pyroglutamate dipeptide gave a hemiaminal. Treatment of the hemiaminal with a catalytic amount of TFA in CH,CI, generated an N-acyliminium ion that was intramolecularly trapped by the side-chain hydroxyl to give a 6.5 or 7,5-bicyclic lactam. (C) 2001 DuPont Pharmaceuticals Company. Published by Elsevier Science Ltd. All rights reserved.