Synthesis and biological activity of vitamin D3 analogues.

Many analogues of vitamin D metabolites including stereochemical isomers and fluorine substituents were synthesized, and their biological activities were determined by in vitro and in vivo assays. Among those analogues, 24,24-F2-1,25-(OH)2D3 and 26,26,26,27,27,27-F6-1,25-(OH)2D3 are more active than the most potent naturally occurring vitamin D3 metabolite, 1,25-(OH)2D3.