Synthesis of a novel 2-vinyl indole
- Vol.58(B), March
- New Delhi CSIR 2019
- 416-419p.
Selectively functionalized 2-vinyl indoles are synthetically active building blocks for the regio and stereo controlled construction of annelated indoles as well as carbazole alkaloids. Various pyrido carbazoles known to have significant antileukaemic activity have been synthesised photochemically from 2-vinyl indoles. A brief survey of literature revealed that there are several methods available for the synthesis of 2-vinyl indoles. In the present work, we herein report a simple and efficient route for the synthesis of a novel 2-vinyl indole. Earlier studies have shown that 1-phenylsulfonyl-2-methyl-3-phenylthioindole undergoes facile side chain bromination to afford 1-phenylsulfonyl-2-bromomethyl-3-phenyl thioindole. This compound is chosen as the starting material for the synthesis of the target molecule. The bromo compound is then converted to its phosphonate ester by heating with triethyl phosphite at 160°C. Then the phosphonate ester is converted to the desired compound namely 4-β-(N-phenylsulfonyl-3-phenylthioindol-2-yl) vinyl benzophenone via Wittig-Horner reaction with 4-benzoyl benzaldehyde. The bright yellow solid thus obtained is found to melt at 158-60°C. It is further characterized by infra-red, 1H and 13C NMR, and mass spectral data. Detailed investigations on the biological activity of similar 2-vinyl indoles will be carried out.