1,3-Dibromo-5,5-dimethylhydantoin → HCID 16092330, compound

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Reaction Steps

16.3 g of dibromodimethylhydantoin were added to a solution of 42.8 g of cholesterol acetate in 300 ml of petroleum ether (40°-60° C.). The reaction mixture was refluxed for 1 hour while stirring thoroughly. After cooling, the solid (dimethylhydantoin) was filtered off; the solvent was distilled off from the filtrate under reduced pressure. In order to remove the last traces of solvent, 100 ml of acetone were added, after which the solution was again evaporated under reduced pressure. The residue was recrystallized from 50 ml of acetone; the α-epimer crystallized out at 0° C. After three recrystallizations from acetone, 12.6 g of pure 7α-bromocholesterol acetate were obtained having a melting-point of 113.9°-115.6° C.; according to the bromine content and the NMR spectrum, the substance was 100% pure.

Provenance & Evidence