Synthetic studies of Vitamin D analogues. X. Synthesis and biological activities of 1α,25-dihydroxy-21-norvitamin D3

Article abstract of DOI:10.1248/cpb.40.648

1α,25-Dihydroxy-21-norvitamin D₃ (3) was synthesized from 1α-hydroxydehydroepiandrosterone (4). Certain biological properties of 3 were examined in comparison with those of 1α,25-dihydroxy vitamin D₃ (1) and 1α,25-dihydroxy-21-nor-20-oxavitamin D₃ (2) to evaluate the effect of the 21-methyl substituent on biological activities. The differentiation-inducing activity of 3 towards human myeloid leukemia cells was approximately one-fifth of that of 1, while in the binding affinity with chick intestinal cytosolic receptor, 3 was about one-tenth of that of 1. The rather weak effect of 3 on serum calcium levels in normal mice at a dosage of 500 μg/kg (intravenous administration) indicates that the essential importance of the 21-methyl moiety may lie in its effect on the regulation of calcium metabolism.

Full text of DOI:10.1248/cpb.40.648

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