Simultaneous Synthesis of Vitamins D, D, D, D, and D from Commercially Available Phytosterol, β-Sitosterol, and Identification of Each Vitamin D by HSQC NMR.

We succeeded in simultaneously synthesizing the vitamin D family, vitamins D, D, D, D, and D, from β-sitosterol, which is sold as a commercially available reagent from Tokyo Chemical Industry Co., Ltd. It is officially sold as a mixture of four phytosterols {β-sitosterol (40-45%), campesterol (20-30%), stigmasterol, and brassicasterol}. Owing to this, we anticipated that, using this reagent, various vitamin D analogs could be synthesized simultaneously. We also synthesized vitamin D from pure cholesterol and analyzed and compared all vitamin D analogs (D, D, D, D, D, and D) by HSQC NMR. We succeeded in clearly demonstrating the difference in the NMR chemical shifts for each vitamin D analog.