CRYSTALLIZATION OF (20R,22R)-2-METHYLENE-19-NOR-22-METHYL-1alpha ,25-DIHYDROXYVITAMIN D3 AND RELATED PRECURSORS

摘要

Disclosed are methods of purifying the compound (20R,22R)-2-methylene-19-nor-22-methyl-1α,25-dihydroxyvitamin D3 to obtain the compound in crystalline form. The methods typically include the steps of dissolving a product containing the compound in a solvent comprising hexane and 2-propanol, cooling the solvent and dissolved product below ambient temperature for a sufficient amount of time to form a precipitate of crystals, and recovering the crystals. Certain diol precursors formed during the synthesis of the compound and its diasteromers also may be obtained in crystalline form using ethyl acetate as a solvent.