[摘要]:The synthesis of 14-epi-1 alpha,25(OH)(2)previtamin D(3), 14-epi-19-nor-1 alpha,25(OH)(2)previtamin D(3), and their 2-substituted analogs is described. The vitamin D receptor (VDR) binding affinity was further evaluated and 2 alpha-methyl substituted 14-epi-1 alpha,25(OH)(2)previtamin D(3) had 17-fold more potent affinity than 14-epi-1 alpha,25(OH)(2)previtamin D(3). In the comparison of these compounds, the effects of thermal equilibrium, with or without 19-carbon at the A-ring, and their CD-ring structures are discussed.