2 results about "Hydroxycholesterols" patented technology

The application discloses a synthesis method of 7-dehydrocholesterol and 25-hydroxy-7-dehydrocholesterol, which comprises the following steps: taking cholesterols as raw materials, and synthesizing the 7-dehydrocholesterol through oxidation, enol esterification and reduction reaction; or taking 25-hydroxycholesterols as raw materials, and synthesizing the 25-hydroxy-7-dehydrocholesterol through oxidation, enol esterification, reduction and hydrolysis reaction. The synthesis route is short, the yield is high, the industrial production is facilitated, and the method has a wide application prospect.

The present invention discloses novel method for synthesizing vegan 25-OH cholesterol / Calcifediol from inexpensive crude phytosterol. According to the method, Phytosterols are reacted to form corresponding i-steroid through tosylation and methanolysis. i-steroid on reductive ozonolysis to C-22 alcohol and conversion via C-22 tosylate to C-22 iodide in good yield. Coupling of C-22 tosylate with Grignard reagent of 4-bromo-2-methyl-2-[(trimethylsilyl)oxy] butane followed by deprotection yielded 25-OH cholesterol. In a process variant, nickel mediated conjugate addition of C-22 iodide to an electron deficient alkene ethyl acrylate and treating corresponding ester with methyl magnesium bromide as means of installing the side chain of 25-OH cholesterol in high yield. Further bromination reaction of 25-OH cholesterol diacetate followed by dehydrobromination using TBAF yielded 25-OH 7-dehydrocholesterol. Further photo reaction of 25-OH 7-dehydrocholesterol in to previtamin D3 using high or medium pressure mercury lamp and subsequent thermal reaction of previtamin D3 to 25-OH vitamin D3(Calcifediol) in good yield.