Crystallization of (20R) 19-nor-24-difluoro-1α,25-dihydroxyvitamin D3
AssigneeWisconsin Alumni Research Foundation
InventorsHector F. DeLuca, Agnieszka Flores, James B. Thoden, Hazel M. Holden
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Abstract
Disclosed are methods of purifying the compound (20R)-19-nor-24-difluoro-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.
Claims7
A compound having the formula
- in crystalline form, and named (20R)-19-nor-24-difluoro-1α,25-dihydroxyvitamin D3,
- wherein the crystalline form has a molecular packing arrangement defined by space group C2 and unit cell dimensions a=23.88 Å, b=6.16 Å, c=19.63 Å, α=90°, β=121.83° and γ=90°.
A method of purifying (20R)-19-nor-24-difluoro-1α,25-dihydroxyvitamin D3, comprising the steps of:
- (a) preparing a solvent comprising hexane;
- (b) adding a product containing (20R)-9-nor-24-difluoro-1α,25-dihydroxyvitamin D3 to be purified to said hexane to form a suspension of the product in the hexane;
- (c) adding 2-propanol dropwise to the suspension to form a mixture of the product in the hexane and 2-propanol;
- (d) heating the mixture to dissolve the product containing (20R)-19-nor-24-difluoro-1α,25-dihydroxyvitamin D- to be purified in said mixture;
- (e) cooling said mixture and dissolved product below ambient temperature for a sufficient amount of time to form a precipitate of (20R)-19-nor-24-difluoro-1α,25-dihydroxyvitamin D crystals;
- and
- (f) separating the (20R)-19-nor-24-difluoro-1α,25-dihydroxyvitamin D3 crystals from the solvent.
Dependencies are inferred from the claim text.