反应详情

温度

45 °C

5-Methoxy-2-[(3,5-dimethyl-4-nitro-2-pyridinyl)methylthio]-1H-benzimidazole (IX) (50 gm, 0.145 mole) was dissolved in methanol and heated to 45° C. A solution of sodium methoxide (50 gm, 0.925 mole) in methanol (150 ml) was added dropwise over a period of 3 hours at 45-60° C. Stirring was continued for another 2 hours and then methanol was distilled off under reduced pressure. To the cooled residue was added water (200 ml) followed by concentrated HCl (65 ml) until the pH of the mixture was 7.5. The reaction mixture was extracted with dichloromethane and the dichloromethane layer was washed with water (2×100 ml). The dichloromethane layer was dried over sodium sulfate and concentrated to yield the product as an amber color syrup. Yield was 40.1 gm, about 83.8% of theoretical. A solid sample was obtained by trituration of the syrup several times with petroleum ether.

1. distillationmethanol was distilled off under reduced pressure
2. additionTo the cooled residue was added water (200 ml)
3. extractionThe reaction mixture was extracted with dichloromethane
4. washthe dichloromethane layer was washed with water (2×100 ml)
5. dry with materialThe dichloromethane layer was dried over sodium sulfate
6. concentrationconcentrated
7. customto yield the product as an amber color syrup