Reaktion #518369

Reaktionsgleichung

cyanocobalamin

trimethylsulfonium bromide

cobalt chloride hexahydrate

sodium borohydride

sodium hydroxide

→

title compound

Mecobalamin

Lösungsmittel

2-butanone

water

butanone

water

Reaktionsbedingungen

Aufarbeitung

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

Vorschrift

To 130 ml of ion-exchanged water were added 10 g of cyanocobalamin, 3.48 g of trimethylsulfonium bromide, 700 mg of cobalt chloride hexahydrate, and 7.5 ml of 2-butanone. After replacing the atmosphere of the system by nitrogen, the whole was warmed on a water bath and a solution of sodium borohydride (4 g)/2N sodium hydroxide (0.2 ml)/water (20 ml) was added dropwise thereto under stirring at an inner temperature of 35° C. After stirring for 3 hours as it was, the mixture was cooled to 15° C. and then stirred overnight. Thereto was added 7.5 ml of butanone, followed by stirring for 2 hours. Then, the precipitates were collected by filtration and dried, to give a crude product of the title compound. Thereto was added 140 ml of a 50% acetone aqueous solution and the mixture was heated at 45° C., filtered and washed with 60 ml of a 50% acetone aqueous solution. After the mixture was adjusted to pH 6.5 with concentrated hydrochloric acid, 475 ml of acetone was added dropwise thereto and the mixture was stirred at 20° C. overnight. Precipitated crystals were collected by filtration and dried, to give 8.94 g of the title compound (yield 90.1%).

Quelle