[EN] A NOVEL PROCESS FOR SYNTHESIS OF RAMELTEON, AND KEY INTERMEDIATES FOR THE SYNTHESIS OF RAMELTEON<br/>[FR] NOUVEAU PROCÉDÉ DE SYNTHÈSE DU RAMELTEON ET INTERMÉDIAIRES CLÉS POUR LA SYNTHÈSE DU RAMELTEON
申请人:CIPLA LTD
公开号:WO2012035303A2
公开(公告)日:2012-03-22
The present invention relates to a novel process for synthesis of ramelteon, and key intermediates for the synthesis of ramelteon.
An efficient and practical process for the synthesis of ramelteon 1, a sedative-hypnotic, is described. Highlights in this synthesis are the usage of acetonitrile as nucleophilic reagent to add to 4,5-dibromo-1,2,6,7-tetrahydro-8H-indeno[5,4-b]furan-8-one 2 and the subsequent hydrogenation which successfully implement four processes (debromination, dehydration, olefin reduction, and cyano reduction) into one step to produce the ethylamine compound 13 where dibenzoyl-l-tartaric acid is selected both as an acid to form the salt in the end of hydrogenation and as the resolution agent. Then, target compound 1 is easily obtained from 13 via propionylation. The overall yield in this novel and concise process is almost twice as much as those in the known routes, calculated on compound 2.