METHOD FOR SYNTHESIZING COUMARIN AND THE DERIVATIVES THEREOF

摘要

The invention relates to an environmentally friendly, heterocatalytic method for synthesizing coumarins based on phenols and carboxylic acids/carboxylic acid derivatives or ss-keto carboxylic acids/carboxylic acid derivatives. Alkylation of the aromatic phenol ring is assisted by an additional functional group of the carboxylic acids/carboxylic acid derivatives while the coumarin unit is formed. High yields can be obtained by using Nafion-silica composite materials. Particularly silica composites that are loaded with 20 to 80 percent of Nafion have a very high activity (compared with pure Nafion resin) due to the high number of acidic cores in connection with the improved active surface thereof. An efficient Pechmann reaction can be carried out by simple preparation in toluene, the catalyst being recyclable and/or regenerable.