Active Vitamin D Analogs with Restricted Conformation Mobility : Synthesis, Receptor Binding and Regulation of Gene Expression

维生素D的构象分析表明，维生素D侧链在空间中移动的区域可以分为四个区域。我们设计了四个构象受限的类似物侧链，只占据这四个空间区中的一个：(20R，22R)-22-甲基-1，25-二羟基维生素D_3(1)，(20R，22S)-22-薄荷基-1，25-二羟基维生素D_3(2)，(20S，22R)-22-薄荷基-1，25-二羟基维生素D_3(3)，(20S，22S)-22-薄荷基-1，25-二羟基维生素D_3(4)。每个类似物都是通过有机铜酸盐与甾体22-烯-24-酮的非对映选择性共轭加成反应来立体选择性地合成的。这些类似物的VDR亲和力被测试并发现在这些地区的Terma中按EG&lt；G&lt；A&lt；EA的顺序增加。结果表明，维生素D与VDR结合的重要空间区域是A和EA。合成了C(4)和C(19)上氟化的维生素D类似物作为探针，用于维生素D-VDR复合体的~1t；19&gt；F-核磁共振分析。利用这些类似物，我们有望分析维生素D与VDR结合时的A环构象。利用重组DNA技术，成功地在10 mg范围内合成了VDR配体结合域。

Conformational analysis of vitamin D indicated that the region in space where vitamin D side chain moves about can be grouped into four. We temed these regions as A,G,EA,and EG.We designed four conformationally restricted analogs side side chains are confined to occupy only one of these four spatial regions : (20R,22R) -22-methyl-1,25-dihydroxyvitamin D_3 (1), (20R,22S) -22-menthyl-1,25-dihydroxyvitamin D_3 (2), (20S,22R) -22-menthyl-1,25-dihydroxyvitamin D_3 (3), (20S,22S) -22-menthyl-1,25-dihydroxyvitamin D_3 (4). Each analog was synthesized stereoselectively via diastereoselective conjugate addition of organocuprate to steroidal 22-en-24-one as the key step. VDR affinities of these analogs were tested and found to increase in the order EG<G<A<EA in termas of the regions. The results indicate that the important spatial regions of vitamin D to bind to VDR are A and EA.Vitamin D analogs fluorinated at C (4) and C (19) were syntherized as probes for ^<19>F-NMR analysis of vitamin D-VDR complex. It is promising that using these analogs we can analyze the A-ring conformation of vitamin D when bind to VDR by ^<19>F NMR.VDR-ligand binding domain was successfully syntherized in ten mg scale by using recombinant DNA technique.