Synthesis of Pyrrolo[4,3,2-<i>de</i>]quinolines from 6,7-Dimethoxy-4-methylquinoline. Formal Total Syntheses of Damirones A and B, Batzelline C, Isobatzelline C, Discorhabdin C, and Makaluvamines A−D
作者:David Roberts、John A. Joule、M. Antonieta Bros、Mercedes Alvarez
DOI:10.1021/jo961743z
日期:1997.2.1
5-tetrahydropyrrolo[4,3,2-de]quinolines 9a, 9d, 9c, respectively. In some cases it was unnecessary to protect the aldehyde function, for example quinolinium salt 12c gave 9j and nitro-aldehyde 6j gave 9e (after BOC protection) directly by reaction with NiCl(2)/NaBH(4). Substitution of the indole and aniline nitrogens in the 1,3,4,5-tetrahydropyrrolo[4,3,2-de]quinolines was based on a combination of
将2-氨基-4-硝基苯酚和2-甲氧基-5-硝基苯胺分别转化为5-硝基喹啉6b和6d,然后将其转化为硝基缩醛6f。将6,7-二甲氧基-4-甲基喹啉(6g)在C-5处硝化,然后将甲基取代基转化为醛6j,然后保护得到缩醛6l。各种方法,特别是大量过量的NiCl(2)/ NaBH(4),用于还原硝基和吡啶环,形成1,2,3,4-四氢喹啉,如7b,7c,7d,在酸性条件下在封闭的条件下分别得到1,3,4,5-四氢吡咯并[4,3,2-de]喹啉9a,9d,9c。在某些情况下,不需要保护醛的功能,例如,通过与NiCl(2)/ NaBH(4)反应直接生成的喹啉盐12c生成9j,硝基醛6j生成9e(在BOC保护后)。1,3,4,5-四氢吡咯并[4,3,2-de]喹啉中吲哚和苯胺氮的取代是基于保护,选择性脱保护以及对吲哚N更大酸性的利用。 -氢。进行8h氯化反应6h,然后如上所述转化,得到氯二胺-缩醛7e,经