Synthesis of 5-arylidene-2,2-dimethyl-1,3- dioxane-4,6-diones and coumarin-3-carbo- xylic acids via reaction of nitrones and Meldrum's acid

摘要

A variety of nitrones have been synthesized and reacted with Meldrum's acid without the aid of any catalysts. Selectively, 5-arylidene-2,2-dimethyl-1,3-dioxane-4,6-diones have been obtained with excellent yields under environmentally benign reaction conditions. Whereas, nitrone of salisylaldehydes with Meldrum's acid afford cyclized products i.e. coumarin-3-carboxylic acids.