A high-yielding cyclocondensation of 4-hydroxycoumarin, phenylglyoxal monohydrate, and heteroarylamines proceeds without catalysis, which gives novel functionalized furo[3,2-c]coumarins and heteroarylamino alkylation of coumarin products in acetonitrile under reflux, is reported for the first time. This tandem process involves sequentially an aldol condensation, Michael addition, a ring closure, and dehydration reaction.
Efficient One-Pot Synthesis of Diphenyl-2,4-dioxa-8,10-diazaspiro-[5.5]undecane-1,5,9-trione Derivatives under Solvent-Free and Catalyst-Free