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Method for preparing L-menthol glyoxylic ester monohydrate with solid acid as catalyst

A technology of menthol glyoxylate and monohydrate is applied in the field of preparation of L-menthol glyoxylate monohydrate to achieve the effects of reducing waste acid discharge, high yield and easy separation

Inactive Publication Date: 2008-10-01
浙江教育学院 +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the problems caused by the use of concentrated sulfuric acid catalysts have not been completely solved

Method used

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  • Method for preparing L-menthol glyoxylic ester monohydrate with solid acid as catalyst
  • Method for preparing L-menthol glyoxylic ester monohydrate with solid acid as catalyst
  • Method for preparing L-menthol glyoxylic ester monohydrate with solid acid as catalyst

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Example 1: SO 4 2- / TiO 2 Preparation of L-Menthol Glyoxylate Monohydrate Catalyzed by Solid Superacid

[0029] Step 1: In a 250mL three-necked flask equipped with a stirrer and a thermometer, add 50g of cyclohexane and 57g of L-menthol, and stir at about 25°C until completely dissolved. Add 0.9 g of SO 4 2- / TiO 2 Solid super acid, slowly add 17.6g glyoxylic acid (50% aqueous solution) dropwise under stirring, the temperature is controlled at 22-26°C, and the addition is completed within half an hour. After the addition, install the upper water separator and condenser tube, stir and heat the reactant to slowly raise the temperature, and reflux for 5 hours. The water taken out is separated by the water separator, and the quality of the water is recorded.

[0030] Step 2: After the reaction, the SO 4 2- / TiO 2 Filter the solid superacid, rinse with cyclohexane, combine the organic layers, adjust the pH to about 5.0 with 10% sodium hydroxide, add sodium bisulfit...

Embodiment 2

[0033] Embodiment 2: reclaim SO 4 2- / TiO 2 Preparation of L-Menthol Glyoxylate Monohydrate Catalyzed by Solid Superacid

[0034] With the 0.78g SO recovered above 4 2- / TiO 2 Solid superacid plus 0.12 g new SO 4 2 - / TiO 2 The solid superacid is used as the catalyst, and the others are operated according to Example 1 to obtain the product: 22.6 grams, the yield: 80.7%, and the GC content: 99.1%.

Embodiment 3

[0035] Embodiment 3: Sodium bisulfate catalyzes preparation of L-menthol glyoxylate monohydrate

[0036] Replace SO with 0.6 g of sodium bisulfate 4 2- / TiO 2 Solid superacid, other operation according to Example 1, product: 21.8 grams, yield: 77.8%, GC content: 99.0%.

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Abstract

The invention discloses a method for preparing the hydrate of L-menthol glyoxylic ester by taking a solid acid as a catalyst. The preparation method takes cyclohexane as a water-carrying agent; a reaction liquid A is obtained by the reflux heating and the water diversion of L-menthol and glyoxylic acid aqueous solution under the catalysis of the solid acid and filtered to remove the solid acid, and an organic phase obtained from separation adjusts pH to 4.9 to 5.1; a sodium bisulfate aqueous solution is added to fully react with the A and the obtained reaction liquid B is separated to obtain a water phase to adjust the pH to 7.1 to 7.5; formaldehyde aqueous solution is added and hydrolysis is carried out to obtain the hydrate of L-menthol glyoxylic ester. The method of the invention takes the solid acid as the catalyst, which is easy to be operated, adopts the catalyst which is easy to be separated and can be recycled, thus reducing waste acid emission during the production process, controlling the formation of side products better and having the advantages of high yield and high product purity, etc.

Description

(1) Technical field [0001] The present invention relates to a kind of preparation method of L-menthol glyoxylate monohydrate (2) Background technology [0002] L-menthol glyoxylate monohydrate (compound I) is an important chiral compound, widely used in the industry of chiral drug raw materials lamivudine (compound II) and etricitabine (compound III) Production is an important chiral source compound in the synthesis of modern chiral compounds. [0003] [0004] The synthetic literature report of L-menthol glyoxylate monohydrate mainly includes: (1) after the esterification of L-menthol and oxalyl chloride, butyl tin reduction (Blanco J.M.et al, Synthesis, 1998, 11:1590-1592) (2) After esterification of L-menthol and butenedioyl chloride, it is obtained after ozonation (Macquarrie D., WO 9622960); (3) After esterification of L-menthol and α-bromoacetyl chloride, it is obtained by Form ester with silver nitrate and react with sodium acetate (WhitesellJ.K.et al, J.Org.Chem...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C69/675C07C69/66C07C67/08C07C67/30B01J27/053
Inventor 游金宗陈亚萍王燕徐彩波顾雅萍蒋善会
Owner 浙江教育学院
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