Synthesis of indole-linked β-cyano-enones: a pathway to indolyl-2-pyrrolones
Nurabul Mondal1, Vidya Kumari1, Danish Ali1
1Department of Chemistry, Indian Institute of Technology Patna, Bihta, Patna-801103, India. lokman@iitp.ac.in.
Abstract:
Herein, we report for the first time an additive- and catalyst-free dehydrogenative multicomponent reaction of arylglyoxal, malononitrile, and indoles for the one-pot synthesis of indole-linked β-cyano-enones in DMF medium. The reaction was performed at 100 °C in DMF, forming one C-C single bond and one CC double bond in a single-flask. Furthermore, we developed an efficient method for the synthesis of indolyl-2-pyrrolones having a hydroxyl group-containing chiral carbon center from the β-cyano-enones using trifluoroacetic acid and water as reaction medium. The β-cyano-enones were also further transformed into indolyl-1,2-diketones via a base-mediated reaction, which yielded indolyl quinoxalines upon reaction with o-phenylenediamine (OPD).
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