Method for preparing L-menthyl glyoxylate-hydrate through catalysis of heteropoly acid

A technology of menthol glyoxylate and monohydrate, applied in the field of medicine, can solve problems such as poor solubility of solid acid, many by-products, complicated reaction, etc., and achieves reduction of discharge of waste acid and salt, improvement of catalytic activity, and improvement of products. good purity

Active Publication Date: 2014-07-30
HANGZHOU NORMAL UNIVERSITY
View PDF7 Cites 4 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0012] In the production technology, concentrated sulfuric acid is used as a catalyst. Although concentrated sulfuric acid has high catalytic activity, the raw materials and products are easily oxidized during the dehydration process, the reaction is complicated, there are many by-products, and subsequent treatment is troublesome; and concentrated sulfuric acid is serious for equipment corrosion, and there are Environmental pollution caused by waste acid discharge
Luo Huajun etc. disclose a kind of use cyclohexane as water-carrying agent, reduce the oxidation of glyoxylic acid and product menthyl ester in the reflux water separation process of L-menthol glyoxylate monohydrate by reducing the pressure. Preparation method, alth

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Method for preparing L-menthyl glyoxylate-hydrate through catalysis of heteropoly acid
  • Method for preparing L-menthyl glyoxylate-hydrate through catalysis of heteropoly acid
  • Method for preparing L-menthyl glyoxylate-hydrate through catalysis of heteropoly acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] Example 1: Catalytic preparation of L-menthol glyoxylate monohydrate by phosphotungstic acid

[0036] Step 1: Add 50 grams of cyclohexane and 57 grams (0.365 mol) of L-menthol into a 250 mL three-necked flask equipped with a stirrer and a thermometer, and stir at about 25°C until completely dissolved. After the addition, install the water separator and condenser, stir and heat the reactant slowly, add 0.5 g of phosphotungstic acid, slowly add 17.6 g of glyoxylic acid with a mass fraction of 50% dropwise under reflux and stirring The aqueous solution (containing 8.8 g of glyoxylic acid) was refluxed for 5 hours. The water taken out is separated by the water separator.

[0037]Step 2: After the reaction is completed, cool down, filter to remove phosphotungstic acid, add sodium sulfite aqueous solution (5 g sodium sulfite (0.040 mol) + 45 g water) to the separated organic layer, and add sodium bisulfite dropwise within 20 to 30 minutes The aqueous solution (8.2 g sodium ...

Embodiment 2

[0039] Example 2: Catalytic preparation of L-menthol glyoxylate monohydrate by phosphotungstic acid

[0040] Use the phosphotungstic acid obtained after the first step of liquid separation in Example 1 to continue to use, no need to add phosphotungstic acid, and operate according to Example 1 to obtain 20.4 grams of product, yield: 72.8%, GC content: 99.1%.

Embodiment 3

[0041] Example 3: Preparation of L-menthol glyoxylate monohydrate catalyzed by silicotungstic acid

[0042] Use 0.5 g of silicotungstic acid instead of phosphotungstic acid, and operate according to Example 1 to obtain a product: 23.4 g, yield: 83.5%, GC content: 99.0%.

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

No PUM Login to view more

Abstract

The invention discloses a method for preparing L-menthyl glyoxylate-hydrate through catalysis of heteropoly acid. The method comprises the following steps: by taking cyclohexane as a water-carrying agent, and heating and backflowing and dehydrating L-menthol and glyoxylic acid water solution under the catalysis of heteropoly acid, to obtain a reaction liquid A; separating the reaction liquid A so as to remove heteropoly acid, and separating to obtain an organic layer; directly adding the organic layer into a sodium sulfite water solution and a sodium hydrogen sulfite water solution, and fully reacting to obtain a reaction liquid B; separating the reaction liquid B to obtain a water layer, regulating the pH value of the water layer to be 6.8-7.5 through base, then adding formaldehyde water solution, and hydrolyzing to obtain the L-menthyl glyoxylate-hydrate. The method is convenient to operate, and the catalysis of the heteropoly acid has both advantages of liquid acid catalysis and solid acid catalysis; the organic layer obtained by filtering the reaction liquid A to remove heteropolyacid, and filtering is not required for the regulation of pH value, so that the emission of waste acid and salt in the production process can be reduced.

Description

technical field [0001] The invention belongs to the technical field of medicine, and relates to a method for preparing L-menthol glyoxylate monohydrate by heteropolyacid catalysis. Background technique [0002] L-menthol glyoxylate monohydrate (compound I) is an important pharmaceutical intermediate widely used in the industrial production of chiral drugs lamivudine (compound II) and emtricitabine (compound III) . [0003] [0004] As an important pharmaceutical intermediate, there are many literature reports on L-menthol glyoxylate monohydrate. Blanco et al. used L-menthol and oxalyl chloride to esterify, and prepared by butyltin reduction. During the reaction, a Dangerous and highly toxic raw materials, not suitable for industrial production (BlancoJ.M.et al, Synthesis, 1998, 11:1590-1592); Silver becomes ester, and then reacts with sodium acetate, and reaction process cost is very high, does not possess suitability for industrialized production condition (Whitesell J...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
IPC IPC(8): C07C69/675C07C67/31
CPCC07C67/08C07C67/31C07C2601/14C07C69/675C07C69/716
Inventor 章鹏飞徐伟明李万梅黄卓豪何红强
Owner HANGZHOU NORMAL UNIVERSITY
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap