反应详情

A mixture of 7.0 g of N,2,2-trimethyl-3,4-dihydro-3-hydroxy-6-nitro-2H-1-benzopyran-4-carbothioamide, 3.0 g of p-toluenesulfonic acid monohydrate, and 300 ml of toluene was heated at reflux for 1 hour. The solvent was removed from the reaction mixture by distillation, and the residue was purified by silica gel column chromatography (developing solution: CH2Cl2). Recrystallizatlon from a mixed solvent of CH2Cl2, diethyl ether, and hexane gave 3.25 g of N,2,2-trimethyl-6-nitro-2H-1-benzopyran-4-carbothioamide represented by formula shown below.

1. temperaturewas heated
2. temperatureat reflux for 1 hour
3. customThe solvent was removed from the reaction mixture by distillation
4. customthe residue was purified by silica gel column chromatography (developing solution: CH2Cl2)