Abstract: The present invention discloses an improved process for extracting cholesterol in high yield and purity from fish oil waste residue. The so obtained cholesterol of pharmaceutical grade is useful as a precursor for the preparation of vitamin D3.

Abstract: The present invention discloses solvent free process for extracting cholesterol free of impurities from milk fat. The so isolated cholesterol is useful for the further preparation of vitamin D3. The present invention further provides pharmaceutical grade cholesterol from milk fat of high purity.

Abstract: The present invention discloses novel method for synthesizing vegan cholesterol and vitamin D3 from inexpensive crude phytosterol.

Abstract: The present invention discloses an improved photochemical synthesis of vitamin D3 from 7-dehydrocholesterol alone or in combination with sterol precursors in presence of the photosensitizer of Formula I in high yield and with reduced levels of impurities.

Abstract: Disclosed herein is an improved and efficient process for synthesis of vitamin D3 and its analogue Calcifediol from Ergosterol. Particularly, the present invention discloses the synthesis of key intermediate 3?-tert-Butyldimethylsilyloxy-22-hydroxy-23,24-bisnorchola-5,7-diene (5), and novel intermediate ?-tert-Butyldimethylsilyloxy-22-iodo-23,24-bisnorchola-5,7-diene (9) by a simple and cost effective process. The industrially viable processes for preparation of said intermediate(s) results in providing provitamins with various side chains and the desired products in high yield.

Abstract: The invention discloses an improved process for production of vitamin D3 from 7-dehydrocholesterol (7-DHC) and to a simple process for recovery unreacted 7-DHC for further reuse. The invention further describes a process for isolation and purification of Vitamin D3.

Abstract: 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.

Abstract: The present invention discloses an improved process for extracting cholesterol in high yield and purity from fish oil waste residue. The so obtained cholesterol of pharmaceutical grade is useful as a precursor for the preparation of vitamin D3.

Abstract: The present invention discloses solvent free process for extracting cholesterol free of impurities from milk fat. The so isolated cholesterol is useful for the further preparation of vitamin D3. The present invention further provides pharmaceutical grade cholesterol from milk fat of high purity.