反应详情

A mixture of 3.61 g of 5-benzoyl-2-(2-pyridylsulfinylmethyl)benzimidazole (0.01 mole), 0.40 g of sodium hydroxide (0.01 mole) and 2 ml of dimethyl sulfate (0.02 mole) in 50 ml of ethanol and 5 ml of water is maintained under reflux for 3 hours. The ethanol is evaporated off and the residue diluted with water and extracted with chloroform. The organic phase is washed with water, dried and evaporated. The residue is chromatographed with silica gel, using chloroform/methanol (99:1) and subsequently chloroform/methanol (95:5) as eluant. On fractional crystallization of the final fraction in ethyl acetate, 0.47 g (12.5%) of 5-benzoyl-1-methyl-2-(2-pyridylsulfinylmethyl)benzimidazole, melting point 174°-177° C., and 1.5 g (40%) of 6-benzoyl-1-methyl-2-(2-pyridylsulfinylmethyl)benzimidazole, melting point 181°-183° C., are obtained.

1. temperatureis maintained
2. temperatureunder reflux for 3 hours
3. customThe ethanol is evaporated off
4. additionthe residue diluted with water
5. extractionextracted with chloroform
6. washThe organic phase is washed with water
7. customdried
8. customevaporated
9. customThe residue is chromatographed with silica gel
10. customOn fractional crystallization of the final fraction in ethyl acetate