Synthesis of 2α- and 2β-substituted-14-epi-previtamin D3 and their genomic activity

2 alpha- and 2 beta-Substituted analogs of 14-epi-previtamin D-3 were synthesized and isolated after thermal isomerization of 14-epi-vitamin D-3 triene at 80 degrees C. The VDR binding affinity and transactivation activity of osteocalcin promoter in HOS cells were tested, and the 2 alpha-methyl-substituted analog was found to have greater genomic activity than 14-epi-previtamin D-3. We found that modification at the C2 position of the seco-steroidal skeleton afforded interesting effects for biological genomic activity for the previtamin D form as well as the natural vitamin D form. (C) 2010 Elsevier Ltd. All rights reserved.