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Preparation method for 7-dehydrochol esterol

A technology for dehydrocholesterol and cholesterol, applied in the field of preparation of 7-dehydrocholesterol, can solve the problems of harmful bromine environment, difficult to remove, difficult to generate conjugated diene structure and the like

Inactive Publication Date: 2008-07-16
BEIJING UNIV OF CHEM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method seems simple, but there are still the following disadvantages: 1. In the process of bromination, the alpha position of the side chain double bond of the esterified cholesterol will also be brominated; mainly because the bromination reaction is a free radical reaction, so the position of the double bond may be transferred; 2. In the process of dehydrobromination, it is not easy to generate the desired conjugated diene structure; 3. There will be other disadvantages when using this method to prepare 7-dehydrocholesterol The required by-products are formed, which requires many steps to remove brominated by-products and other corresponding by-products; 4. Bromine is harmful to the environment and is not easy to remove; 5. Bromine has an impact on the later photoreaction

Method used

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  • Preparation method for 7-dehydrochol esterol
  • Preparation method for 7-dehydrochol esterol
  • Preparation method for 7-dehydrochol esterol

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0058] a) Take 5g (grams) of cholesterol and add it to 36.8ml (milliliters) of acetic anhydride, add two zeolites and reflux at 140°C±5°C for 3h to generate cholest-5ene-3-acetate. The acetic anhydride is analytically pure and has a density of 540g / 500ml.

[0059] The purity of the cholest-5-ene-3-acetate formed by the reaction was determined by the internal standard method, and the yield was 87%.

[0060] b) Dissolve 5 g of cholest-5-ene-3-acetate and 4 equivalents of anhydrous sodium acetate in 40 ml of glacial acetic acid, shake well at 25°C, and then heat to 59°C±1°C in a water bath. Take 2 equivalents of CrO 3 (Chromium trioxide) was added to the reaction solution in stages, first less and then more, first slow and then fast, and the addition was completed within 30 minutes (minutes). Stir at 59°C±1°C for 4.5h, cool to 25°C, then cool with water at 4°C for 12h, crystals will precipitate, use a glass sand core funnel to filter, and then wash the crystals with deionized w...

Embodiment 2

[0068] a) Dissolve 5 g of cholesterol in 40 ml of dried benzene, then add 2 equivalents of acetic anhydride, reflux at 80° C. for 3 h. After the reaction solution is cooled to 25°C, wash it with 1% dilute hydrochloric acid to weak acidity and then use 5% NaHCO 3 (sodium bicarbonate) aqueous solution to weak alkaline, and finally to neutral with deionized water. The aqueous phase was extracted 3 times with an appropriate amount of ether, and the benzene layers after the three extractions were combined and washed with anhydrous Na 2 SO 4 dry. The dried benzene-ether solution was rotary evaporated to obtain 5.44 g of cholest-5-ene-3-acetate.

[0069] The tested purity is 97%, and the yield of cholest-5-ene-3-acetate is greater than 95%.

[0070] b) Dissolve 4ml of tert-butanol peroxide with a volume fraction of 70% and 1.71g (4mmol) of cholest-5-ene-3-acetate in 16ml of dichloromethane, and stir at 25°C for 24h, Then the solvent was rotary evaporated to obtain 2.61 g of soli...

Embodiment 3

[0074] In this embodiment, step b) is different from Embodiment 1, and other steps are the same as those in Embodiment 1. Step b) of the present embodiment is:

[0075] Take 2.0 grams of cholesterol acetate and 0.029 equivalent of cuprous iodide, dissolve it in 30 ml of benzene, and finally add 5.6 equivalents of tert-butyl hydroperoxide. Under the protection of nitrogen, the reaction was stirred at 70°C for 26h.

[0076] The obtained cholest-5-ene-7-carbonyl-3-acetate solid was checked for purity and the calculated yield was 30%.

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Abstract

The invention discloses a preparation method of a 7-dehydrocholesterol, which comprises the following steps: a) protecting a hydroxyl on the 3 position of a cholesterol; b) oxidizing a carbon on the 7 position of the product made in step a) into a carbonyl; c) carrying out hydrazone reaction to the product made in step b) with hydrazine derivatives, the structure of the hydrazine derivatives being at most one H to be substituted by the following hydrazine; d) reacting the product made in step c) with a strong basic reagent having stronger alkaline than a sodium hydroxide; e) reacting the product made in step d) with water or an acid. In the preparation method, no halogen group elements such as Br element are participated, the side effects are less and the yield is high, and the prepared product is safe and innocuous.

Description

technical field [0001] The invention relates to the field of organic synthesis, in particular to a preparation method of 7-dehydrocholesterol. The method can prepare 7-dehydrocholesterol using cholesterol as a raw material under bromine-free conditions. Background technique [0002] Vitamin D (vitamin D) is a class of substances with anti-rickets activity, also known as D vitamins, belonging to fat-soluble vitamins. Vitamin D 3 It is a kind of vitamin D, also known as cholecalciferol, and its molecular formula is C 27 h 43 OH, the relative molecular mass is 384.65. It is a colorless needle-like crystal or white crystalline powder, odorless, easily deteriorated when exposed to light or air; insoluble in water, easily soluble in ethanol, acetone, chloroform or ether, slightly soluble in vegetable oil; melting point is 84 ℃ ~ 88°C, the structure is as follows: [0003] [0004] Vitamin D is an essential fat-soluble vitamin for the growth, reproduction, maintenance of l...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07J9/00C07C401/00
Inventor 谭天伟张立
Owner BEIJING UNIV OF CHEM TECH
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