Gu Rong, Hameurlaine Ahmed, Dehaen Wim
Department of Chemistry, University of Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium.
J Org Chem. 2007 Sep 14;72(19):7207-13. doi: 10.1021/jo0711337. Epub 2007 Aug 15.
A facile three-stage, one-pot approach for the synthesis of a variety of novel 6-monosubstituted and 6,12-disubstituted 5,11-dihydroindolo[3,2-b]carbazoles, in moderate to good yields (20-50%), has been developed, based on the condensation of an indole and an aldehyde with a catalytic amount of iodine, followed by an acid-catalyzed intramolecular cyclization with an ortho ester. The parent indolo[3,2-b]carbazoles (ICZs) could be converted to various functional derivatives. Both N-alkylation and N-arylation were successfully accomplished, and azo-coupling, formylation, as well as bromination were performed in a regioselective way leading to the formation of novel functional 6,12-disubstituted indolo[3,2-b]carbazoles. Starting from a monoformylated indolocarbazole, novel benzimidazolyl-substituted derivatives were synthesized, while Suzuki cross-couplings on a monobrominated building block afforded a novel pathway toward functionally arylated ICZs.
基于吲哚和醛在催化量碘存在下的缩合反应，随后与原酸酯进行酸催化的分子内环化反应，已开发出一种简便的三步一锅法来合成多种新型的6-单取代和6,12-二取代的5,11-二氢吲哚并[3,2-b]咔唑，产率适中至良好（20 - 50%）。母体吲哚并[3,2-b]咔唑（ICZs）可转化为各种功能衍生物。N-烷基化和N-芳基化均成功实现，并且重氮偶联、甲酰化以及溴化反应均以区域选择性方式进行，从而形成新型功能化的6,12-二取代吲哚并[3,2-b]咔唑。从单甲酰化吲哚咔唑出发，合成了新型苯并咪唑基取代的衍生物，而在单溴化结构单元上进行的铃木交叉偶联反应为功能化芳基化ICZs提供了一条新途径。
