Reaktion #1440231

Reaktionsgleichung

sodium borohydride

cyanocobalamin

cobalt chloride hexahydrate

trimethylsulfoxonium bromide

→

title compound

Methylcobalamin

Lösungsmittel

2-butanone

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONwas added dropwise
2. 2
   workup.STIRRINGAfter stirring for further 30 minutes as it
3. 3
   workup.WAITover 30 minutes
4. 4
   workup.STIRRINGThe mixture was stirred for further 3 hours as it
5. 5
   workup.STIRRINGby stirring overnight at a bath temperature of 15° C
6. 6
   SonstigeThe resulting precipitates
7. 7
   Filtrationwere collected by filtration
8. 8
   Sonstigedried

Vorschrift

To 390 ml of ion-exchanged water were added 3 0 g of cyanocobalamin, 2.1 g of cobalt chloride hexahydrate, and 22.5 ml of 2-butanone. While blowing nitrogen gas at the flow rate of 15 ml/min. in to the system, the mixture was heated in a water bath, to which an aqueous solution of sodium borohydride (12 g/60 ml) was added dropwise under stirring at the internal temperature of 30° C. over 2 hours. After stirring for further 30 minutes as it was, an aqueous solution of trimethylsulfoxonium bromide (11.5 g/60 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 86%.

Quelle