1-Desoxy analog of 2MD: Synthesis and biological activity of (20S)-25-hydroxy-2-methylene-19-norvitamin D3
作者:Izabela Sibilska、Katarzyna M. Barycka、Rafal R. Sicinski、Lori A. Plum、Hector F. DeLuca
DOI:10.1016/j.jsbmb.2010.03.063
日期:2010.7
During our ongoing structure-activity studies in the vitamin D area, we obtained (20S)-1 alpha,25-dihydroxy-2-methylene-19-norvitamin D-3 (5). This analog, designated 2MD, is characterized by a significantly enhanced calcemic activity and is currently evaluated as a potential drug for osteoporosis. Therefore, it was of interest to synthesize also its 1-desoxy analog and to evaluate its biological action. These studies were aimed at solving an intriguing problem: can such a vitamin also be hydroxylated in vivo at the allylic C-1 position despite lack of the exomethylene moiety at C-10? The Wittig-Horner coupling of the known protected (20S)-25-hydroxy Grundmann ketone 17 and the phosphine oxides 16 and 33, differing in their hydroxyls protection, provided the target 1-desoxy-2MD (6) after removal of the silyl protecting groups. Two synthetic paths have been elaborated leading to the desired A-ring synthons and starting from commercially available compounds:1,4-cyclohexanedione monoethylene acetal (7) and (-)-quinic acid (19). The biological activity in vitro of the synthesized 1-desoxy-2MD (6) was evaluated and this analog was found to have an affinity for the vitamin D receptor (VDR) similar as its parent compound 2MD (5) while being much less active in the transcriptional assay. The results of the biological tests in vivo are also discussed. (C) 2010 Published by Elsevier Ltd.