Method for preparing 7-dehydrogenized cholesteryl ester from 7-tosylhydrazones-3-cholesteryl ester

A technology of p-toluenesulfonylhydrazone and dehydrocholesteryl ester, which is applied in the field of organic chemical synthesis, can solve the problems of high production cost, reaction selectivity and low product yield, achieve short reaction time, significantly reduce production cost, and improve The effect of product purity

Inactive Publication Date: 2016-06-08
ZHEJIANG NHU CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the reaction, the alkali reagent is insoluble in the solvent, and both the main reactant and the product are easily soluble, so the above reaction is a typical heterogeneous reaction, and the reaction is only carried out on the solid surface of the alkali re...

Method used

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  • Method for preparing 7-dehydrogenized cholesteryl ester from 7-tosylhydrazones-3-cholesteryl ester
  • Method for preparing 7-dehydrogenized cholesteryl ester from 7-tosylhydrazones-3-cholesteryl ester
  • Method for preparing 7-dehydrogenized cholesteryl ester from 7-tosylhydrazones-3-cholesteryl ester

Examples

Experimental program
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Effect test

Embodiment 1

[0038] Swell 10 g of chloromethylated polystyrene resin (2% divinylbenzene cross-linked, 55 mequivCl per gram of resin, 80-100 mesh) in anhydrous tetrahydrofuran for 1 h, add anhydrous potassium carbonate 3.72 g (27.6 mmol) and 9.04g of 4'-aminobenzo-18-crown ether-6 (27.6mmol), and in 80ml of anhydrous tetrahydrofuran solution, stirred and refluxed under nitrogen flow, filtered the resin after cooling, washed with acetone, water and acetone successively, and then Extracted with acetone and dried, a light yellow resin can be obtained. The latter is refluxed with excess sodium methoxide solution until it does not contain Cl, and then filtered, extracted with acetone and dried in vacuum to obtain a polystyrene resin-supported 4'-aminobenzo-18-crown-6 catalyst.

[0039]

Embodiment 2

[0041]Swell 10g of chloroethylated polystyrene resin (2% divinylbenzene crosslinked, 55 mequivCl per gram of resin, 80-100 mesh) in anhydrous tetrahydrofuran for 1 hour, add anhydrous potassium carbonate 3.72g (27.6mmol) and 7.82g of 4'-aminobenzo-15-crown-5 (27.6mmol), and in 80ml of anhydrous tetrahydrofuran solution, stirred and refluxed under nitrogen flow, filtered the resin after cooling, washed with acetone, water and acetone successively, and then Extracted with acetone and dried, a light yellow resin can be obtained. The latter is refluxed with excess sodium methoxide solution until it does not contain Cl, and then the product is obtained after filtration, extraction with acetone and vacuum drying.

Embodiment 3

[0043] Swell 10 g of chloromethylated polystyrene resin (2% divinylbenzene cross-linked, 55 mequivCl per gram of resin, 80-100 mesh) in anhydrous tetrahydrofuran for 1 h, add anhydrous potassium carbonate 3.72 g (27.6 mmol) and 10.86g4,4'-diaminodibenzo-18-crown-6 (27.6mmol). And in 80ml of anhydrous tetrahydrofuran solution, stirred and refluxed under a nitrogen stream, the resin was cooled and filtered, followed by acetone, water and acetone After washing, extraction with acetone and drying, a light yellow resin can be obtained. The latter is refluxed with excess sodium methoxide solution until it does not contain Cl, and then the product is obtained after filtration, extraction with acetone and vacuum drying.

[0044] Replace the crown ethers used above, such as 8-crown-6, benzo-18-crown-6, dibenzo-18-crown-6, 15-crown-5, benzo15-crown-5, 12 -crown-4, dicyclohexane-18-crown-6, dibenzo-15-crown-5, etc., can obtain a variety of different polystyrene resin supported crown eth...

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Abstract

The invention discloses a method for preparing 7-dehydrogenized cholesteryl ester from 7-tosylhydrazones-3-cholesteryl ester. In an existing method, cholesteryl ester is subjected to esterification, oxidation, hydrazone compounding, hydrazone removing and hydrolyzation to obtain 7-dehydrogenized cholesteryl ester, wherein a hydrazone removing reaction is a typical heterogeneous reaction and is only carried out on the solid surface of an alkali reagent; consequently, the reaction selectivity and the product yield are not high, and thus the production cost is high. The method is characterized in that a crown ether phase transfer catalyst supported by polystyrene resin is adopted for a hydrazone removing reaction. By means of the method, a heterogeneous reaction is converted into a homogeneous reaction, the reaction selectivity is improved, and the conversion rate can be remarkably increased, and the production cost is lower while the product quality is improved. Meanwhile, crown ether obtained after modification and immobilization can be applied repeatedly, and thus the toxicity of common crown ether on the environment is avoided.

Description

technical field [0001] The invention belongs to the field of organic chemical synthesis, in particular to a method for preparing 7-dehydrocholesteryl ester from 7-p-toluenesulfonylhydrazone-3-cholesterol ester by using a phase transfer catalytic method. Background technique [0002] Vitamin D 3 It is one of the important vitamins essential for human health and normal growth and reproduction of livestock. Its raw material 7-dehydrocholesterol mainly has the following chemical synthesis process routes: [0003] (1) Bromination / dehydrobromination method: This method was proposed by Ziegler in 1942. The first step is to connect a bromine atom to the allyl position of cholesteryl ester, and in the next dehydrobromination reaction , often form two isomers, that is, not only the target product 5,7-diene cholesteryl ester, but also 4,6-diene cholesteryl ester, and then 7-dehydrocholesterol is obtained after hydrolysis and crystallization. The total yield reported in this process l...

Claims

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Application Information

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IPC IPC(8): C07J9/00B01J31/02B01J31/06
CPCC07J9/00B01J31/0297
Inventor 姚祥华孙瑞瑞陈发
Owner ZHEJIANG NHU CO LTD
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