Synthesis and Anti-inflammatory Properties of 1α,25-Dihydroxy-16-ene-20-cyclopropyl-24-oxo-vitamin D₃, a Hypocalcemic, Stable Metabolite of 1α,25-Dihydroxy-16-ene-20-cyclopropyl-vitamin D₃

1α,25(OH)2-16-ene-20-cyclopropyl-vitamin D3 (13) is several fold more potent than the natural hormone 1α,25-dihydroxyvitamin D3 (1) as an anti-inflammatory agent. Here, we have further analyzed the anti-inflammatory properties of 13, confirming it as the most potent analogue tested within this family. We then determined the structures of all the natural metabolites of 13, including the 24-oxo metabolite 14, and carried out its synthesis. A...