Vitamin D metabolites, analogs, and their preparation and application are discussed in many references in the patent and other literature, as for example, in U.S. Pat. No. 3,565,924 directed to 25-hydroxycholecalciferol; U.S. Pat. No. 3,697,559, directed to 1,25-hydroxycholecalciferol; U.S. Pat. No. 3,741,996 directed to 1.alpha.-hydroxycholecalciferol, and U.S. Pat. No. 3,907,843 directed to 1.alpha.-hydroxyergocalciferol. Fluorinated vitamin D derivatives and methods for preparing such compounds are the subject of U.S. Pat. No. 4,196,133 directed to 24,24-difluoro-25-hydroxyvitamin D.sub.3 ; U.S. Pat. No. 4,201,881 directed to 24,24-difluoro-1.alpha.,25-dihydroxyvitamin D.sub.3 ; and U.S. Pat. Nos. 4,188,345, 4,229,357, 4,229,358, 4,226,787 and 4,224,230.
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