反应详情

温度

70 °C

A solution of 6-[(2-chloro-α,α,α,6-tetrafluoro-p-tolyl) oxy]-α-methyl-1H-benzotriazole-1-acetaldehyde dimethyl acetal (23.0 g, 0.053 mole) in acetic acid is treated with 54 ml of 2.5N H2 SO4 and heated at 70° C. for 12 hours. A portion of the reaction solution is concentrated, diluted with acetone and treated portionwise, at 25°-38° C., with an aqueous solution of KMnO4 (23.7 g, 0.15 mole). Addition is continued until a persistent pink color is obtained at 27° C. The reaction mixture is filtered to remove MnO2 and the filtrate is concentrated in vacuo to give a residue. Addition of water to the thus-obtained residue precipitates the title compound as a pale yellow solid, 16.6 g. A sample is recrystallized twice from 75% aqueous ethanol to afford a crystalline solid, mp 174°-175.5° C., identified by elemental and NMR analyses.

1. concentrationA portion of the reaction solution is concentrated
2. additiondiluted with acetone
3. additionAddition
4. customis obtained at 27° C
5. filtrationThe reaction mixture is filtered
6. customto remove MnO2
7. concentrationthe filtrate is concentrated in vacuo
8. customto give a residue
9. customprecipitates the title compound as a pale yellow solid, 16.6 g
10. customA sample is recrystallized twice from 75% aqueous ethanol
11. customto afford a crystalline solid, mp 174°-175.5° C.