Synthesis of a biologically active vitamin D2 metabolite

The Centennial Collection of VDR Ligands: Metabolites, Analogs, Hybrids and Non-Secosteroidal Ligands

Since the discovery of vitamin D a century ago, a great number of metabolites, analogs, hybrids and nonsteroidal VDR ligands have been developed. An enormous effort has been made to synthesize compounds which present beneficial properties while attaining lower calcium serum levels than calcitriol. This structural review covers VDR ligands published to date.

Synthesis of 24(28)-Methylene-1α-Hydroxyvitamin D3, a Novel Vitamin D3 Analogue

24(28)-Methylene-1α-hydroxyvitamin D3 was synthesised in 13 steps from vitamin D2. The key step of the synthesis involved the Wittig–Horner olefination of a nor-vitamin D2 aldehyde with diethylphosphono-3-methyl-2-butanone. The resulting enone was followed by reduced methylenation, photoisomerisation and deprotection then gave the target compound.

Synthesis and Structure-Activity Relationships of Bioactive Compounds Using Sterols

Sterols are widely and abundantly distributed in nature. It is convenient to utilize them for the preparation of useful compounds such as pharmaceuticals with steroid and secosteroid skeletons. This paper describes the synthesis and structure-activity relationships of naturally occurring active forms of vitamin D analogues, sterols having neurite outgrowth activity, and liver X receptor agonist. The active form of vitamin D(4) showed similar biological activities but had higher affinity to the vitamin D-binding protein compared with the corresponding vitamins D(2) and D(3). This shows that the active form of vitamin D(4) is a good candidate for an agent to replace the active forms of vitamins D(2) and D(3). In the course of screening for low molecular-weight compounds that exhibit neurite outgrowth activity in the culture broth, we found that the natural product dictyosterol showed strong activity. From screening of the analogues, it was found that the double bond between C22 and C23 in the side chain of the sterol is essential for its activity. Ergost-22-ene-1alpha,3beta-diol was found to serve as a stronger liver X receptor agonist than 24(S), 25-epoxycholesterol, which regulates the expression of genes involved in lipid metabolism. Structure-function study showed that the 1alpha-hydroxyl group, the saturated steroid structure, and the double bond between C22 and C23 are needed to function as a liver X receptor agonist.