反应详情

A mixture of 41.7 g of 2,2-bisfluoromethyl-6-nitro-2H-1-benzopyran-4-carboxylic acid, 20 ml of sulfuric acid and 300 ml of ethyl alcohol was heated to reflux for 6 hours. The reaction mixture was poured into ice water and the precipitated crystals were filtered off to give 42.7 g of 2,2-bisfluoromethyl-6-nitro-2H-1-benzopyran-4-carboxylic acid ethyl ester; m.p. 96-98° C.;

1. temperaturewas heated
2. temperatureto reflux for 6 hours
3. filtrationthe precipitated crystals were filtered off