PROCESS AND INTERMEDIATE FOR CERTAIN BIS-AZA-BICYCLIC ANXIOLYTIC AGENTS

摘要

(C1-C3)Alkyl-4,6,7,8,9,9a-hexahydro-2H,3H-pyrido-[1,2-a]pyrazin-1-one- 7-carboxylate esters, important precursors to certain bis-aza-bicyclic anxiolytics, can be prepared from di(C1-C3)alkyl cis-piperidine-2,5-dicarboxylate starting material by a new process via a new class of intermediates, di(C1-C3)alkyl cis-N-(2-(phthalimido)ethyl)piperidine-2,5-dicarboxylates. In the process, the starting material is reacted with either 2-(phthalimido)ethyl triflate or 2-(phthalimido)acetaldehyde to form the new intermediate, which can then be cyclized to the aforementioned precursor.