Studies on the Syntheses of 7, 8-Disubstituted 1-Benzylisoquinoline and Related Compounds. (4). Synthesis of dl-Cularidine
作者:HIDEO IIDA、HONG-CHING HSU、TOYOHIKO KIKUCHI
DOI:10.1248/cpb.21.1001
日期:——
Bischler-Napieralski reaction of phenolic bromo amide (VIII), which was obtained from the Schotten-Baumann reaction of 4-benzyloxy-2-bromo-5-hydroxyphenethylamine (VI) with 2-bromo-4, 5-dimethoxyphenylacetyl chloride (VII) and then reduction with NaBH4 of the resultant dihydroisoquinoline (IX) gave 7-benzyloxy-5-bromo-1-(2-bromo-4, 5-dimethoxybenzyl)-8-hydroxy-1, 2, 3, 4-tetrahydroisoquinoline(X). N-Methylation of X afforded XI. The Ullmann reaction of XI in the presence of potassium carbonate and cupric oxide in pyridine gave 6-benzyloxy-4-brome-1-methyl-9, 10-dimethoxy-1, 2, 3, 12, 12a-pentahydrobenzoxepino[2, 3, 4-i, j]isoquinoline (XII). Subsequent debenzylation and debromination of XII with hydrogen over 10% palladium-charcol gave dl-cularidine (Id) which was identified with natural cularidine by infrared and nuclear magnetic resonance spectral comparisons.
4-benzyloxy-2-bromo-5-hydroxyphenethylamine (VI) 与 2-bromo-4、5-二甲氧基苯乙酰氯(VII)的 Schotten-Bumann 反应,然后用 NaBH4 还原生成的二氢异喹啉(IX),得到 7-苄氧基-5-溴-1-(2-溴-4, 5-二甲氧基苄基)-8-羟基-1, 2, 3, 4-四氢异喹啉(X)。X 的 N-甲基化反应得到 XI。在碳酸钾和氧化铜存在下,XI 在吡啶中发生乌尔曼反应,得到 6-苄氧基-4-溴-1-甲基-9,10-二甲氧基-1,2,3,12,12a-五氢苯并氧杂卓[2,3,4-i,j]异喹啉(XII)。随后,XII 在 10%的钯-羰醇上用氢进行脱苄基和脱溴反应,得到了 dl-考来啶 (Id),通过红外光谱和核磁共振光谱的比较,可以确定其为天然考来啶。