Syntheses of 3-substituted coumarins by the condensation reaction of salicylaldehyde with activated methylene compounds （ethyl cyanoacetate, malonic acid） are discussed in media of ionic liquids--（2-hydroxyethyl）a...Syntheses of 3-substituted coumarins by the condensation reaction of salicylaldehyde with activated methylene compounds （ethyl cyanoacetate, malonic acid） are discussed in media of ionic liquids--（2-hydroxyethyl）ammonium carboxylates （formates, acetates, lactates） without utilization of any other catalysts. The dependence of yields of the reaction product is investigated on the structure of ionic liquids （their cations, anions, total polarity and pseudo-pH values）. 3-Substituted coumarins are prepared in high yields in media of these environmentally friendly ionic liquids which serve simultaneously as reaction media and as catalysts. The mentioned ionic liquids are prepared by reactions of corresponding hydroxyethyl-amines with carboxylic acids, and their quantitative analyses being made by potentiometric titration of ionic liquids with perchloric acid in 100% acetic acid.展开更多
文摘Syntheses of 3-substituted coumarins by the condensation reaction of salicylaldehyde with activated methylene compounds （ethyl cyanoacetate, malonic acid） are discussed in media of ionic liquids--（2-hydroxyethyl）ammonium carboxylates （formates, acetates, lactates） without utilization of any other catalysts. The dependence of yields of the reaction product is investigated on the structure of ionic liquids （their cations, anions, total polarity and pseudo-pH values）. 3-Substituted coumarins are prepared in high yields in media of these environmentally friendly ionic liquids which serve simultaneously as reaction media and as catalysts. The mentioned ionic liquids are prepared by reactions of corresponding hydroxyethyl-amines with carboxylic acids, and their quantitative analyses being made by potentiometric titration of ionic liquids with perchloric acid in 100% acetic acid.
