Synthesis and Biological Activity of 1α-Hydroxy-24, 24-dimethyl-22E-dehydrovitamin D₃ and 1α, 25-Dihydroxy-24, 24-dimethyl-22E-dehydrovitamin D₃

抄録

Two new vitamin D₃ analogues, 1α-hydroxy-24, 24-dimethyl-22E-dehydrovitamin D₃ (13) and 1α, 25-dihydroxy-24, 24-dimethyl-22E-dehydrovitamin D₃ (17), which are blocked for 24-hydroxylation by the methyl groups, were synthesized from 1α, 3β-bismethoxymethoxypregn-5-ene-20Scarbaldehyde (6) by using the orthoester Claisen rearrangement for construction of the carbon skeleton of their side chains. These compounds (13 and 17) elicited a rise in serum calcium, but not in serum inorganic phosphorus in rats. In a bioassay for alkaline phosphatase, they were found to show much weaker activity than 1α-hydroxy vitamin D₃ (5).