Preparation of 3,4-di-O-acetyl-L-rhamnal

A technology of rhamnetose and acetyl group, applied in 3 fields, can solve the problems of high cost, complicated intermediate product processing and the like, and achieve the effect of reducing cost

Inactive Publication Date: 2009-08-05
CHENGDU INST OF BIOLOGY CHINESE ACAD OF S
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] The purpose of the present invention is to solve the disadvantages of 3,4-di-O-acetyl-L-rhamnosyl in the preparation method of high cost, cumbersome intermediate product treatment and nee...

Method used

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  • Preparation of 3,4-di-O-acetyl-L-rhamnal
  • Preparation of 3,4-di-O-acetyl-L-rhamnal
  • Preparation of 3,4-di-O-acetyl-L-rhamnal

Examples

Experimental program
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example 1

[0019] Example 1: Add 1.0g rhamnose, 5.0mL acetic acid, 3.5mL acetic anhydride, and 20mg p-toluenesulfonic acid to a 50mL round bottom flask, stir and react at room temperature for 10 minutes, then add 1.25 acetyl bromide to the reaction solution mL, methanol 0.8mL, and react in the dark for 1 hour. The reaction solution was extracted with dichloromethane, the organic phase was washed 3 times with water, 2 times with saturated aqueous sodium bicarbonate solution, and 1 time with saturated aqueous sodium chloride solution, then dried by adding anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure to obtain 1- Bromo-2,3,4-tri-O-acetyl-L-rhamnose crude.

[0020] Dissolve the generated 1-bromo-2,3,4-tri-O-acetyl-L-rhamnose in 5 mL of ethyl acetate, then add 20 mL of saturated sodium dihydrogen phosphate aqueous solution and 4 g of zinc powder, and react for 1 hour. Filtrate, extract the filtrate 3 times with ethyl acetate, combine the organic phases, wash...

example 2

[0021] Example 2: Add 1.0g rhamnose, 10mL acetic acid, 3.5mL acetic anhydride, 20mg catalytic amount of perchloric acid to a 50mL round bottom flask, stir and react at room temperature for 30 minutes, then add 1.25mL acetyl bromide to the above reaction solution , methanol 0.8mL, and react in the dark for 2 hours. The reaction solution was extracted with dichloromethane, the organic phase was washed 3 times with water, 2 times with saturated aqueous sodium bicarbonate solution, 1 time with saturated aqueous sodium chloride solution, dried by adding anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure to obtain 1-bromo - Crude 2,3,4-tri-O-acetyl-L-rhamnose.

[0022] Dissolve the resulting 1-bromo-2,3,4-tri-O-acetyl-L-rhamnose in 10 mL of ethyl acetate, add 20 mL of phosphate buffer (made from 4.4 g of disodium hydrogen phosphate, 5.6 g of phosphoric acid Prepared by sodium dihydrogen and 20mL water) and 4g zinc powder, reacted at room temperature for ...

example 3

[0023] Example 3: Add 1.0g rhamnose, 7mL acetic acid, 3.5mL acetic anhydride, 20mg catalytic amount of zinc chloride to a 50mL round bottom flask, stir and react at room temperature for 1.5 hours, then add 1.25mL acetyl bromide to the above reaction solution , methanol 0.8mL, and react in the dark for 3 hours. The reaction solution was extracted with dichloromethane, the organic phase was washed 3 times with water, 2 times with saturated aqueous sodium bicarbonate solution, and 1 time with saturated aqueous sodium chloride solution, dried by adding anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure to obtain 1-bromo - Crude 2,3,4-tri-O-acetyl-L-rhamnose.

[0024] Dissolve the resulting crude 1-bromo-2,3,4-tri-O-acetyl-L-rhamnose in 8 mL of acetone, then add 20 mL of saturated potassium dihydrogen phosphate aqueous solution and 4 g of zinc powder, and react for 5 hours. Filtrate, extract the filtrate 3 times with ethyl acetate, combine the organic p...

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Abstract

The invention belongs to the technical field of organic chemistry, and particularly relates to a method for preparing 3,4-di-O-acetyl-L-rhamnal. The method comprises that: firstly, under the catalytic action of p-toluenesulfonic acid(perchloric acid, amido-sulfonic acid, zinc chloride and sulphuric acid), L-rhamnal reacts with acetic acid and acetic anhydride to obtain 1,2,3,4-tetra-O-acetyl-L-rhamnose; the 1,2,3,4-tetra-O-acetyl-L-rhamnose is added with acetyl bromide and methanol for reaction to generate 1-bromine-2,3,4-tri-O-acetyl-L-rhamnose; and the 1-bromine-2,3,4-tri-O-acetyl-L-rhamnose is added with ethyl acetate(acetone), an aqueous solution of disodium hydrogen phosphate(a phosphate buffer and a solution of potassium phosphate dibasic) and the zinc powder for reaction to generate the 3,4-di-O-acetyl-L-rhamnal. The method has the characteristics of easy operation, short process flow, high yield, short reaction time, low cost, little 'three wastes', little environmental pollution, easy industrialization and the like.

Description

technical field [0001] The invention belongs to the technical field of organic chemistry, and in particular relates to a preparation method of 3,4-di-O-acetyl-L-rhamnosyl sugar. Background technique [0002] In the synthesis of natural products and active polysaccharides, 3,4-di-O-acetyl-L-rhamnoside sugar is an important raw material. At present, the preparation methods of 3,4-di-O-acetyl-L-rhamnosyl sugar that can be retrieved mainly include the following types. Such as: (1) Carbohydr. Res. 2000, 329, 861-872. [0003] [0004] Another example: (2) Tetrahedron: Asymmetry 2005, 16, 283-293. [0005] [0006] Another example: (3) Tetrahedron Letters 2003, 44, 7863-7866. [0007] [0008] All the above-mentioned synthetic methods can obtain products, but there are different shortcomings such as expensive raw materials, cumbersome operations, and intermediate products that need to be separated and purified. Contents of the invention [0009] The purpose of the p...

Claims

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Application Information

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IPC IPC(8): C07D309/30
Inventor 邵华武赵晋忠魏善巧马小锋
Owner CHENGDU INST OF BIOLOGY CHINESE ACAD OF S
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