Reaktion #518368

Reaktionsgleichung

cyanocobalamin

trimethylsulfoxonium bromide

cobalt chloride hexahydrate

sodium borohydride

sodium hydroxide

→

title compound

Mecobalamin

Lösungsmittel

2-butanone

water

2-butanone

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturthe mixture was heated in a water bath
2. 2
   workup.STIRRINGAfter stirring for 2 hours as it
3. 3
   Temperaturthe mixture was cooled to 15° C.
4. 4
   workup.STIRRINGstirred overnight
5. 5
   workup.STIRRINGby stirring for 1 hour
6. 6
   FiltrationThen, the precipitates were collected by filtration
7. 7
   Sonstigedried

Vorschrift

To 650 ml of ion-exchanged water were added 50 g of cyanocobalamin, 19.51 g of trimethylsulfoxonium bromide, 3.5 g of cobalt chloride hexahydrate and 37.5 ml of 2-butanone. After replacing the atmosphere of the system by nitrogen, the mixture was heated in a water bath and a solution of sodium borohydride (20 g)/2N sodium hydroxide (1 ml)/water (100 ml) was added dropwise thereto under stirring at an inner temperature of 35° C. After stirring for 2 hours as it was, the mixture was cooled to 15° C. and then stirred overnight. Thereto was added 37.5 ml of 2-butanone, followed by stirring for 1 hour. Then, the precipitates were collected by filtration and dried, to give a crude product of the title compound. Thereto was added 700 ml of a 50% methanol aqueous solution, and the mixture was heated at 40° C., filtered and washed with 300 ml of a 50% acetone aqueous solution. After the mixture was adjusted to pH 6.5 with concentrated hydrochloric acid, methanol was evaporated. To the residue was added dropwise 2250 ml of acetone, followed by stirring at 20° C. overnight. Precipitated crystals were collected by filtration and dried, to give 45.0 g of the title compound (yield 90.7%).

Quelle