3-Methyl-2-butanone → CID 10898559

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

To 390 ml of ion-exchanged water were added 30 g of cyanocobalamin, 14.61 g of trimethylsulfoxonium iodide, 900 mg of iron (II) sulfate heptahydrate, 900 mg of cobalt chloride hexahydrate and 22.5 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 (12 g)/2N sodium hydroxide (1 ml)/water (60 ml) was added dropwise thereto under stirring at an inner temperature of 20° C. After stirring for 3 hours as it was, the mixture was cooled to 10° C. and then stirred overnight. Thereto was added 24 ml of 3-methyl-2-butanone, followed by stirring for 2 hours. Then, the precipitates were collected by filtration and dried, to give 35 g of a crude product of the title compound. Thereto was added 300 ml of a 50% methanol aqueous solution and the mixture was heated at 35° C, filtered and washed with 120 ml of a 50% methanol aqueous solution. After the mixture was adjusted to pH 7.0 with concentrated hydrochloric acid, 1365 ml of acetone was added dropwise thereto and the mixture was stirred at 10° C. overnight. Precipitated crystals were collected by filtration and dried, to give 25.9 g of the title compound (yield 86.3%).

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