Synthesis of some carbazolequinone alkaloids and their analogues. Facile palladium-assisted intramolecular ring closure of arylamino-1,4-benzoquinones to carbazole-1,4-quinones.
作者:Motoi YOGO、Chihiro ITO、Hiroshi FURUKAWA
DOI:10.1248/cpb.39.328
日期:——
Carbazolequinone alkaloids, murrayaquinone-A (1a), and pyrayaquinone-A (2) and -B (3), as well as pyrano[3, 2-b]carbazolequinone 5, an isomer of 2 and 3, were prepared conveniently by the palladium-assisted intramolecular ring closure of the corresponding 2-arylamino-methyl-1, 4-benzoquinones 9a and 9i-k. A series of their analogues, 6-, 7-, and 8-substituted 3-methylcarbazole-1, 4-quinone derivatives 1b-g and 2-methylcarbazolequinones 6a-g corresponding to 1a-g, was also prepared in the same manner. Comparative analysis of the carbon-13 nuclear magnetic resonance spectra was found to provide useful information for the structural assignment of either 2- or 3-methylcarbazolequinones.
碳唑醌生物碱、毛果杨梅醌-A(1a)、 pyrayaquinone-A(2)和-B(3),以及吡喃[3, 2-b]碳唑醌5(2和3的异构体),通过钯催化的分子内环闭合反应,便捷地从相应的2-芳基氨基-甲基-1, 4-苯醌(9a和9i-k)合成而成。此外,还以相同的方法合成了系列类似物,包括6-、7-和8-取代的3-甲基碳唑-1, 4-醌衍生物(1b-g)以及与1a-g对应的2-甲基碳唑醌(6a-g)。碳-13核磁共振谱的比较分析提供了对2-或3-甲基碳唑醌结构分配的有用信息。