434-16-2Relevant articles and documents
Oxidation of cholesterol by a biomimetic oxidant, cetyltrimethylammonium dichromate
Patel, Sabita,Mishra
, p. 3522 - 3526 (2006)
The oxidation of cholesterol by cetyltrimethylammonium dichromate (CTADC) in dichloromethane (DCM) yielded 7-dehydrocholesterol, while with addition of acetic acid in DCM the product was found to be 5-cholesten-3-one. The kinetics of oxidation of cholesterol by CTADC in DCM, in the presence of acid, was investigated with change in [acid], [cholesterol], [CTADC], [surfactant], temperature, and solvents. The reaction was found to be first order with acetic acid and fractional order with CTADC and cholesterol. Michaelis-Menten-type kinetics was observed with respect to cholesterol. The solvent isotope effect was found to be k(D2O)/k(H2O) = 0.72. The observed experimental data suggest that the reaction occurs in reversed micellar system, akin to an enzymatic environment, and the reaction path involves the intermediate formation of an ester complex, which undergoes decomposition to give the product.
Novel industrial method for preparing vitamin D3 by taking stigmasterol as raw material
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Paragraph 0010; 0052; 0053, (2021/05/05)
The invention provides a novel industrial method for preparing vitamin D3 by taking stigmasterol as a raw material. The method comprises the following steps: sequentially carrying out hydroxyl acetylation, side chain oxidation, side chain isopentane reduction and hydrogenation on stigmasterol to obtain cholesterol acetate, and then sequentially carrying out oxidation, hydrazone formation, hydrazone removal, hydrolysis, illumination and the like to obtain the vitamin D3. The invention provides a novel method for preparing vitamin D3 from stigmasterol, and the method has the advantages of mild reaction conditions and high yield, and is suitable for industrial production.
PREPARATION OF 7-DEHYDROCHOLESTEROL USING SPECIFIC AROMATIC SOLVENTS
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Page/Page column 16, (2021/10/30)
The present invention relates to a new synthesis of 7- dehydrocholesterol or itsOH-protected forms of the formula I by the reaction of a compound of formula (ll)in the presence of a solvent of formula (III), comprising the step (a) wherein a salt of the formula (II) is added to a solvent of the formula (III) at a temperature of between 60 °C and the boiling point of said solvent. This process leads to a significant reduction in the level of the by-product of formula (V).
ORGANIC SOLVENT NANOFILTRATION OF 7-DEHYDROCHOLESTEROL OR 25-HYDROXY-7-DEHYDROCHOLESTEROL OR THEIR OH PROTECTED FORMS
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Page/Page column 20, (2021/10/30)
The present invention relates to the purification of 7-dehydrocholesterol or 25-hydroxy-7-dehydrocholesterol or their OH-protected forms, respectively. It has been found that the process using organic solvent nanofiltration allows an efficient reduction of the amount of a new higher molecular compound which is formed in a 5 new synthesis process of of 7-dehydrocholesterol or 25-hydroxy-7-dehydrocholes- terol or their OH-protected forms in small amounts. Said new higher molecular compound can be used as colorant.
Preparation method of 7-dehydrocholesterol for production of vitamin D3
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, (2021/04/07)
The invention particularly discloses a preparation method of 7-dehydrocholesterol for production of vitamin D3. The preparation method comprises the following steps: an esterification reaction, a bromination reaction, a debromination reaction and a saponification hydrolysis reaction. The esterification reaction comprises the following steps: adding cholesterol, an acid-binding agent and a solid catalyst into petroleum ether, carrying out heating to 45-50 DEG C in a nitrogen atmosphere, dropwise adding benzoyl chloride, performing heating to 78-82 DEG C after dropwise adding, conducting stirring for a reaction for 3-5 hours, adding distilled water to quench the reaction, performing filtering to obtain filter residues and a filtrate, extracting the filter residues with distilled water, concentrating an oil layer, then adding acetone, carrying out a reflux reaction for 30-40 minutes, conducting cooling to 20-30 DEG C, and performing filtering to obtain cholesterol benzoate; and soaking, filtering and drying the filter residues to obtain a solid desiccant, and repeatedly using the solid desiccant. The method has the advantage of facilitating cyclic utilization of the catalyst.
Methods for preparing cholesterol, and derivatives and analogs thereof
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, (2021/04/07)
The present invention relates to the field of pharmaceutical chemistry, and in particular to methods of preparing cholesterol,and derivatives and analogs thereof. The cholesterol derivatives include, but not limited to, 7-dehydrocholesterol, 25-hydroxycholesterol, 25- hydroxy7dehydrocholesterol and ergosterol. In the invention, phytosterol can be used as a raw material to prepare the compound shown in the formula I through microbial conversion, and then cholesterol and the derivatives and analogues thereof are prepared.
IMPROVED, COST EFFECTIVE PROCESS FOR SYNTHESIS OF VITAMIN D3 AND ITS ANALOGUE CALCIFEDIOL FROM ERGOSTEROL
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Page/Page column 23; 43, (2021/01/29)
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 3β-tert-Butyldimethylsilyloxy-22-hydroxy-23,24-bisnorchola-5,7-diene (5), and novel intermediate β-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.
New industrial method for producing vitamin D3 by taking wool fat as raw material
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Paragraph 0045; 0046, (2019/06/13)
The invention provides a new industrial method for producing vitamin D3 by taking wool fat as a raw material. The new industrial method comprises the following steps: carrying out saponification and primary purification on the wool fat in a low alcohol solution, thus obtaining a cholesterol crude product; directly carrying out acetylation on the cholesterol crude product, thus obtaining high-purity cholesterol acetate; then sequentially carrying out oxidizing, hydrazone forming, hydrazone removing, hydrolyzing, illuminating and the like, thus obtaining the vitamin D3. A production technology disclosed by the invention is efficient, green and environment-friendly, is high in product yield and is suitable for industrial production, and the manufacturing cost of the vitamin D3 is greatly reduced; a saponification technology is ingenious in filtrate treatment, has no generation of waste liquid and waste and is more beneficial for environment protection.
Synthesis and biological activity evaluation of novel peroxo-bridged derivatives as potential anti-hepatitis B virus agents
Jia, Menglu,Zhao, Rui,Xu, Bing,Yan, Wenqiang,Chu, Fuhao,Gu, Hongshun,Xie, Tianxin,Xiang, Hongjun,Ren, Jian,Chen, Dagang,Wang, Penglong,Lei, Haimin
supporting information, p. 148 - 151 (2017/02/05)
Previous studies have demonstrated that natural steroid compounds containing a peroxide bridge exhibited potential anti-hepatitis B virus activity. To continue our research, a simple and regioselective methodology, using Eosin Y as a clean photosensitized oxidation catalyst, was developed for the synthesis of a peroxide bridge in steroids. The method that using Eosin Y as the catalyst was exposed to visible light and furbished in high yields, did not involve tedious work-up or purification, and avoided using environmentally hazardous solvents. It can be regarded as a green protocol. Moreover, a series of cholesterol and β-sitosterol derivatives containing a peroxide bridge were synthesized using this method and screened for their anti-HBV activity. Among the compounds synthesized in this research, 5α,8α-cyclicobioxygen-6-vinyl-3-oxo-cholesterone (1f, 3.13 μg ml?1) had the most potent activity with inhibition rates of 77.45% ± 6.01% and 58.73% ± 8.64% on the secretion of HBsAg and HBeAg antigens, respectively, after 8 days. Further acute toxicity test showed that the LD50 value of compound 1f was 362.46 mg kg?1 after an intraperitoneal injection in mice. Moreover, structure-activity relationships of cholesterol and β-sitosterol derivatives were briefly discussed.
PROCESS FOR PREPARATION OF 7-DEHYDROCHOLESTEROL
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Page/Page column 14, (2015/11/27)
The invention discloses an improved cost-effective process for preparation of 7-Dehydrocholesterol of formula I with good yield and purity, comprising:a) epimerizing 7(alpha+beta) bromo protected cholesterol in presence of tetrabutyl ammonium bromide in toluene or a ketonic solvent or combinations thereof to obtain predominantly 7.alpha-bromo 3-protected cholesterol; b) Reacting 7.apha-bromo 3- protected cholesterol with substituted or unsubstituted thiophenol or its salts in presence of a liquor ammonia to obtain predominantly 7β-thiophenyl)-3-protected cholesterol; c) Oxidizing 7. beta. - thiophenyl 3-protected cholesterol in presence of Cumene hydrogen peroxide and Titanium tetraisopropoxide to obtain 7. beta. -phenyl sulfoxide 3-protected cholesterol; d) Converting 7. beta. -phenyl sulfoxide 3-protected cholesterol into 7-Dehydro 3-protected cholesterol in presence of base; e) purifying 7-Dehydro 3-protected cholesterol by suspending in a suitable organic solvent; and f) Deprotecting the 7-Dehydro 3-protected cholesterol by treating with alkali in presence of methanol to obtain 7-Dehydrocholesterol followed by purification of 7-Dehydrocholesterol from an organic solvent.
