Iodine-mediated one-pot synthesis of 3-cyanocoumarins and 3-cyano-4-methylcoumarins

Abstract

2-Hydroxybenzaldehydes 1a-e on reaction with malononitrile (2) in the presence of iodine as catalyst give 3-cyanocoumarins 3a-e in one step under thermal heating as well as under microwave irradiation. The latter conditions are much more efficient in terms of time (2-5 min) and yield as compared to the thermal conditions (2-2.5 h). Following a similar procedure, 3-cyano-4-methylcoumarins 3f-i were also prepared by the reaction of 2-hydroxyacetophenones 1f-i with 2. © 2014 SCS. All rights reserved.