N-carbomethoxy-5-ethyl, 1,2-dihydropyridine (1) may be prepared by the bromination of N-carbomethoxy-3-ethyl-1,2,5,6-tetrahydropyridine (10), and subsequent double dehydrobromination with EtAlCl2/HMPA; this diene undergoes Diels-Alder reaction with dimethyl methylenemalonate (2) to give the isoquinuclidine (3), an intermediate in our planned approach to catharanthine.
N-羰基甲氧基-5-乙基,1,2-
二氢吡啶(1)可以通过将N-羰基甲氧基-3-乙基-1,2,5,6-四氢
吡啶(10)
溴化,然后再用EtAlCl进行两次脱氢
溴化来制备2 / HMPA;该二烯与
亚甲基丙二酸二甲酯(2)进行Diels-Alder反应,得到异喹核苷(3),这是我们计划中的Catharanthine方法的中间体。