Design and synthesis of potent vitamin D receptor antagonists with A-ring modifications: remarkable effects of 2alpha-methyl introduction on antagonistic activity

Bioorg Med Chem. 2003 Aug 15;11(17):3621-31. doi: 10.1016/s0968-0896(03)00371-7.

Abstract

Novel A-ring analogues of the vitamin D receptor (VDR) antagonist (3a), ZK-159222, and its 24-epimer (3b) were convergently synthesized. Preparation of the CD-ring portions with the side chains of 3a,b, followed by palladium-catalyzed cross-coupling with the A-ring enyne precursors (15a,b), (3S,4S,5R)- and (3S,4S,5S)-bis[(tert-butyldimethylsilyl)oxy]-4-methyloct-1-en-7-yne, afforded the 2alpha-methyl-introduced analogues (4a,b) and their 3-epimers (5a,b). The biological profiles of the hybrid analogues were assessed in terms of affinity for VDR, and antagonistic activity to inhibit HL-60 cell differentiation induced by the natural hormone, 1alpha,25-dihydroxyvitamin D(3). The analogue 4a showed an approximately fivefold higher antagonistic activity compared with 3a. The 2alpha-methyl introduction into 3a increased the receptor affinity, thereby enhancing VDR antagonism. This approach to design potent antagonists based on hybridization of structural motifs in the A-ring and in the side chain may prove to be valuable.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcitriol / analogs & derivatives*
  • Calcitriol / chemical synthesis
  • Calcitriol / pharmacology
  • Cattle
  • Drug Design
  • Molecular Structure
  • Palladium / chemistry
  • Receptors, Calcitriol / antagonists & inhibitors*
  • Receptors, Calcitriol / metabolism
  • Structure-Activity Relationship

Substances

  • Receptors, Calcitriol
  • ZK159222
  • Palladium
  • Calcitriol