Synthesis and anti-inflammatory properties of 1alpha,25-dihydroxy-16-ene-20-cyclopropyl-24-oxo-vitamin D3, a hypocalcemic, stable metabolite of 1alpha,25-dihydroxy-16-ene-20-cyclopropyl-vitamin D3.

1alpha,25(OH)(2)-16-ene-20-cyclopropyl-vitamin D(3) (13) is several fold more potent than the natural hormone 1alpha,25-dihydroxyvitamin D(3) (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.