Novel 9-Alkyl- and 9-Alkylidene-Substituted 1α,25-Dihydroxyvitamin D3 Analogues: Synthesis and Biological Examinations

J Med Chem. 2015 Aug 13;58(15):6237-47. doi: 10.1021/acs.jmedchem.5b00795. Epub 2015 Aug 5.

Abstract

Continuing the structure-activity relationship studies in the vitamin D area, we designed and synthesized novel C-9 substituted calcitriol analogues, possessing different nonpolar groups at this position. 9α-Methyl-1α,25-(OH)2D3, both epimers of 9-methylene-10,19-dihydro-1α,25-(OH)2D3 as well as the parent vitamin with the "reversed" triene system, 9-methylene-19-nor-1α,25-(OH)2D3, were obtained from the previtamin D precursors, constructed by either Suzuki-Miyaura, Sonogashira, or Stille couplings of the corresponding A- and C,D-ring fragments. An alternative synthetic path, leading to the latter vitamin and its homologue with 9-ethylidene group, involved formation of dienynes as precursors of the respective 19-norprevitamin D compounds. 9β-Methyl-19-nor-1α,25-(OH)2D3 was prepared by homogeneous hydrogenation with Wilkinson catalyst, and this analogue was found to be the most active in vitro. Moreover, 9α-methyl-1α,25-(OH)2D3 and 9-methylene-19-nor-1α,25-(OH)2D3 showed some in vitro activity, however, the in vivo assays indicated only weak calcemic potency of these compounds in the intestinal calcium transport.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chromatography, High Pressure Liquid
  • Crystallography, X-Ray
  • In Vitro Techniques
  • Proton Magnetic Resonance Spectroscopy
  • Vitamin D / analogs & derivatives*
  • Vitamin D / chemical synthesis
  • Vitamin D / chemistry
  • Vitamin D / pharmacology

Substances

  • dihydroxy-vitamin D3
  • Vitamin D