1182-06-5Relevant articles and documents
Hunziker
, p. 917,921 (1955)
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Schaltegger
, (1950)
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Preparation method of 7-dehydrocholesterol for production of vitamin D3
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Paragraph 0028-0033; 0036, (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.
Process for synthesis of 5α-cholest-8(14)-en-3β-ol-15-one and other 15-oxygenated sterols
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, (2008/06/13)
A process for preparing 15-oxygenated sterols, such as 3β-hydroxy-5α-cholest-8(14)-ene-15 one, comprising converting 7-dehydrocholesterol to 3β-benzoyloxycholesta-5,7-diene, converting the 3β-benzoyloxycholesta-5,7-diene to a 3β-benzoyloxy-5-cholesta-7,14-diene, converting the 3β-benzoyloxy-5-cholesta-7,14-diene to a 3β-benzoyloxy-14α, 15α-epoxy-5-cholest-7-ene and converting the 3β-benzoyloxy-14α, 15α-epoxy-5-cholest-7-ene to a 15-oxygenated sterol. Preferably, the 3β-benzoyloxy-cholesta-5,7-diene is converted to a 3β-benzoyloxy-5-cholesta-7,14-diene by (i) contacting 3β-benzoyloxy-cholesta-5,7-diene, in a solvent at a temperature of at most about -55° C., with HCl at a concentration of at least about 2.0 M for a time sufficient to convert the 3β-benzoyloxycholesta-5,7-diene to a 3β-benzoyloxy-5-cholesta-7,14-diene; (ii) neutralizing the resultant reaction mixture with a base to prevent formation of a significant amount of 3β-benzoyloxy-5-cholesta-8,14-diene; and (iii) recovering the 3β-benzoyloxy-5-cholesta-7,14-diene.
