反应详情

温度

38 °C

To 65 ml of ion-exchanged water were added 5 g of cyanocobalamin, 0.35 g of cobalt chloride hexahydrate, and 3.75 ml of 2-butanone. After replacing the inside atmosphere of the system with nitrogen gas, the mixture was heated in a water bath, to which an aqueous solution of sodium borohydride (2 g/10 ml) was added dropwise under stirring at a bath temperature of 38° C. over 60 minutes. After stirring for further 30 minutes as it was, an aqueous solution of trimethylsulfoxonium bromide (1.9 g/10 ml) was further added thereto over 30 minutes. The mixture was stirred for further 3 hours as it was, followed by stirring overnight at a bath temperature of 15° C. The resulting precipitates were collected by filtration and dried to give a crude product of the title compound. To the crude product was added a 50% acetone aqueous solution. After heating at 35° C., the mixture was adjusted to pH 7.0 with concentrated hydrochloric acid. Then, acetone was added dropwise thereinto and the mixture was stirred overnight. The precipitated crystals were collected by filtration and dried, to give the title compound in a yield of 85%. Physical properties of the resulting methylcobalamin:

1. additionwas added dropwise
2. stirringAfter stirring for further 30 minutes as it
3. waitover 30 minutes
4. stirringThe mixture was stirred for further 3 hours as it
5. stirringby stirring overnight at a bath temperature of 15° C
6. customThe resulting precipitates
7. filtrationwere collected by filtration
8. customdried