反应详情

2-(2'-Hydroxy-5'-hydroxyethylphenyl)-2H-benzotriazole (150 g, 0.59 mol), methacrylic acid (55 ml, 0.65 mol), hydroquinone (2.4 g), p-toluenesulfonic acid monohydrate (3 g) and toluene (2 l) were placed in a 3 liter flask equipped with a Dean and Stark receiver. After 1.5 hours of refluxing the mixture, another 2.7 g of p-toluenesolfonic acid monohydrate was added and the refluxing was continued for another 15.5 hours. Approximately 10 ml of water was collected (theoretical: 10.6 g) and the yield of the desired compound was 93.7% as judged by a gas chromatography. Another 1 g of p-toluenesolfonic acid monohydrate was added and the reflusing was continued for another 3 hours. A yield of 95.6% was shown by a gas chromatography. After cooling the reaction mixture, it was washed with aqueous sodium hydrogen carbonate solution, water, 5% hydrochloric acid and water. The organic layer was dried with anhydrons magnesium sulfate and chromatographed through an alumina (Fisher, 80-200 mesh) column. After evaporation of the solvent, the residue was recrystallized from distilled methanol twice. Yield: 141.8 g (74%); Purity: >99.9% (G.C.). The IR and NMR data were consistent with the structure.

1. customequipped with a Dean and Stark receiver
2. temperatureAfter 1.5 hours of refluxing the mixture
3. customApproximately 10 ml of water was collected (theoretical: 10.6 g)
4. additionAnother 1 g of p-toluenesolfonic acid monohydrate was added
5. waitthe reflusing was continued for another 3 hours
6. temperatureAfter cooling the reaction mixture, it
7. washwas washed with aqueous sodium hydrogen carbonate solution, water, 5% hydrochloric acid and water
8. dry with materialThe organic layer was dried with anhydrons magnesium sulfate
9. customchromatographed through an alumina (Fisher, 80-200 mesh) column
10. customAfter evaporation of the solvent
11. customthe residue was recrystallized
12. distillationfrom distilled methanol twice