(Z)-3-(2, 4, 5-Trimethoxy-3-methylbenzylidene)-1, 6-dimethylpiperazine-2, 5-dione (7a) was prepared by a simple regioselective C-monomethylation of (Z)-4-(4-methoxybenzyl)-3-(2, 4, 5-trimethoxy-3-methylbenzylidene)-1-methyl-piperazine-2, 5-dione (3) followed by deprotection. Compound 7a was also prepared from (S)-1, 4-diacetyl-3-methylpiperazine-2, 5-dione (8) and the benzaldehyde derivative (9) in five steps as an optically active form. It was shown to be a useful intermediate for the preparation of novel octahydro-1, 5-imino-3-benzazocin-4, 7, 10-trione derivatives having a methyl group at the C-2 position, as ABC ring models of saframycins.
(Z)-3-(2, 4, 5-
三甲氧基-3-甲基亚苄基)-1, 6-二甲基
哌嗪-2, 5-二酮(7a)是由(Z)-4-(4-甲氧基苄基)-3-(2, 4, 5-
三甲氧基-3-甲基亚苄基)-1-甲基-
哌嗪-2, 5-二酮(3)通过简单的区域选择性 C-单甲基化反应制备的,然后进行脱保护。化合物 7a 也是由 (S)-1,4-
二乙酰基-3-甲基
哌嗪-2,5-二酮 (8) 和
苯甲醛衍
生物 (9) 经过五个步骤制备而成,具有光学活性。结果表明,它是制备新型八氢-1,5-亚
氨基-3-苯并氮杂环辛-4,7,10-三酮衍
生物的有用中间体,这些衍
生物的 C-2 位有一个甲基,是
黄樟素的 ABC 环模型。