The synthesis of 2,4-dimethyl-6 H-pyrido[3,2-b]carbazole (2a) and of its 9-methoxy (2b) and 9-hydroxy (2c) derivatives via the Combes-Beyer reaction is described. Pyridocarbazole 2a has been obtained by two different routes. In the course of the synthesis of 2b either a partial or a total demethoxylation has been observed depending on the route employed.

中文翻译：

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2,4-二甲基-6 H-吡啶并[3,2-b]咔唑，是通过Combes-Beyer反应制得的抗肿瘤生物碱玫瑰树碱的异构体。

描述了通过Combes-Beyer反应合成2,4-二甲基-6 H-吡啶并[3,2-b]咔唑（2a）及其9-甲氧基（2b）和9-羟基（2c）衍生物。吡啶并咔唑2a已通过两种不同的途径获得。在合成2b的过程中，根据所采用的途径，已观察到部分或全部脱甲氧基化。