State Key Laboratory of Drug Research, Department of Medicinal Chemistry, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai 201203, China.
School of Pharmacy, University of Chinese Academy of Sciences, No.19A Yuquan Road, Beijing 100049, China.
Molecules. 2019 Mar 8;24(5):960. doi: 10.3390/molecules24050960.
Bisindolyl alkaloids represent a large family of natural and synthetic products that display various biological activities. Among the bisindole compounds, 6,7,12,13-tetrahydro-5-cyclohepta[2,1-:3,4-]diindoles have received little attention. Only two methods have been developed for the construction of the 6,7,12,13-tetrahydro-5-cyclohepta[2,1-:3,4-]diindole scaffold thus far, including the classical Fischer indole synthesis conducted by reacting indole-fused cycloheptanone and hydrazines, and the condensation reaction to build the seven-membered ring. Here, we report for the first time a new route to synthesize 6,7,12,13-tetrahydro-5-cyclohepta[2,1-:3,4-]diindoles through intramolecular oxidative coupling of 1,3-di(1-indol-3-yl)propanes in the presence of PIFA, DDQ and TMSCl with moderate to excellent yields.
双茚基生物碱是一个庞大的天然和合成产物家族，具有多种生物活性。在双吲哚类化合物中，6,7,12,13-四氢-5-环庚[2,1-:3,4-]二吲哚受到的关注较少。迄今为止，仅开发出两种构建 6,7,12,13-四氢-5-环庚[2,1-:3,4-]二吲哚骨架的方法，包括通过反应吲哚稠合的环己烷酮和肼进行的经典 Fischer 吲哚合成，以及缩合反应构建七元环。在这里，我们首次报道了一种通过 PIFA、DDQ 和 TMSCl 存在下的 1,3-二(1-吲哚-3-基)丙烷的分子内氧化偶联来合成 6,7,12,13-四氢-5-环庚[2,1-:3,4-]二吲哚的新途径，产率中等至优秀。
