Wing R M, Okamura W H, Pirio M R, Sine S M, Norman A W
Science. 1974 Dec 6;186(4167):939-41. doi: 10.1126/science.186.4167.939.
Solution conformations of the A and seco B rings of vitamin D(3), 1(alpha), 25-dihydroxyvitamin D(3), 1(alpha)-hydroxyvitamin D(3), and dihydrotachysterol(3) have been established by high resolution, 300-megahertz proton magnetic resonance spectroscopy. The A ring of these steroids is dynamically equilibrated between two chair conformers. For vitamin D(3), 1(alpha)-hydroxyvitamin D(3), and 1(alpha),25-dihydroxyvitamin D(3) the relative proportions of the two conformers are 1 : 1, whereas dihydrotachysterol3 exists principally as only one conformer. Thus, the substituent groups on the A ring may be either equatorially or axially oriented, and suggests a refinement of the existing topological model for vitamin D hormonal activity.
已通过高分辨率300兆赫质子磁共振光谱法确定了维生素D(3)、1(α),25-二羟基维生素D(3)、1(α)-羟基维生素D(3)和二氢速甾醇(3)的A环和开环B环的溶液构象。这些甾体的A环在两个椅式构象体之间动态平衡。对于维生素D(3)、1(α)-羟基维生素D(3)和1(α),25-二羟基维生素D(3)，两种构象体的相对比例为1:1，而二氢速甾醇(3)主要仅以一种构象体存在。因此，A环上的取代基可以是平伏取向或直立取向，这表明对现有的维生素D激素活性拓扑模型进行了改进。
