Reaktion #1440232

Reaktionsgleichung

trimethylsulfoxonium bromide

cyanocobalamin

cobalt chloride hexahydrate

sodium borohydride

→

title compound

Methylcobalamin

Lösungsmittel

2-butanone

water

Reaktionsbedingungen

Aufarbeitung

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

Vorschrift

To 13 L of ion-exchanged water were added 1 Kg of cyanocobalamin, 70 g of cobalt chloride hexahydrate, and 750 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 (400 g/2 L) was added dropwise while keeping and stirring at the internal temperature of 35° C.±5° C. over 120 minutes. An aqueous solution of trimethylsulfoxonium bromide (383 g/2 L) 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 87%.

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