Vinyl azides in heterocyclic synthesis. Part 9. Synthesis of the isoquinolone alkaloid siamine by intramolecular aza-Wittig reaction
作者:Michael Kennedy、Christopher J. Moody、Charles W. Rees、Juan J. Vaquero
DOI:10.1039/p19870001395
日期:——
incorporates an intramolecular aza-Wittig reaction as the key step. The benzaldehyde (5), prepared from the benzoic acid (2) by the dihydro-oxazole method, is converted into the vinyl azides (6) and (7), which on treatment with triethyl phosphite give the isoquinolone (8) and the 1-ethoxyisoquinoline (9) respectively. The synthesis is completed by transformation of the isoquinoline 3-ester (9) into
异喹诺酮生物碱siamine(1)是通过3,5-二苄氧基苯甲酸(2)通过将分子内aza-Wittig反应作为关键步骤的途径合成的。由苯甲酸(2)通过二氢-恶唑法制得的苯甲醛(5)转化为叠氮化乙烯基酯(6)和(7),在用亚磷酸三乙酯处理后得到异喹诺酮(8)和1 -乙氧基异喹啉(9)。合成由异喹啉-3-基酯(转化完成9)插入相应的3-甲基异喹啉(12),用三溴化硼将其完全脱烷基,得到siamine(1)。