Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

Method for synthesizing L-menthol

A synthesis method and menthol technology, applied in the synthesis field of L-menthol, can solve the problems of difficult industrial application, complicated process, low yield and the like, and achieve the effects of high yield, simple process and low price

Inactive Publication Date: 2009-12-16
SHANGHAI WANXIANG FLAVORS & FRAGRANCES
View PDF2 Cites 18 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The general chemical synthesis process can only obtain racemic menthol, and often needs to obtain L-menthol by chiral resolution or other means, which has defects such as complex process and low yield; while the process adopted in Chinese patent 1258597 needs lipase to catalyze dissociated from D, L- The preparation of L-menthol from base derivatives is difficult to achieve industrial application because the activity of the enzyme is affected by various external factors

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 synthesizing L-menthol
  • Method for synthesizing L-menthol

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] The synthesis of embodiment 1 L-menthol

[0024] 1. Amination reaction.

[0025] Replace the 1L three-necked bottle equipped with electromagnetic stirring, reflux condenser, constant pressure dropping funnel, suction head and thermometer into a nitrogen atmosphere, and add freshly steamed myrcene (80%, 82-84 ° C / 4mmHg, 173.3g, 218mL, 1.02mol), diethylamine (140g, 200mL, 1.91mol), slowly add n-BuLi (93mL, 2.2M in ether, 0.205mol, 20mol%) dropwise under stirring, and add dropwise for 70min After completion, the water bath was heated to 60° C. and stirred for 7 hours, then the heating was stopped, and the system was allowed to return to room temperature naturally, and slowly poured into 1 L of ice water, stirring continuously during this period. The layers were separated, the aqueous phase was extracted with ether (3×300 mL), the organic phases were combined, washed with 500 mL of water, and dried over anhydrous sodium sulfate. The desiccant was removed by suction filt...

Embodiment 2

[0042] The synthesis of embodiment 2 L-menthol

[0043] 1. Amination reaction.

[0044] Replace the 1L three-necked bottle equipped with electromagnetic stirring, reflux condenser, constant pressure dropping funnel, suction head and thermometer into a nitrogen atmosphere, and add freshly steamed myrcene (80%, 82-84 ° C / 4mmHg, 173.3g, 218mL, 1.02mol), diethylamine (140g, 200mL, 1.91mol), slowly add n-BuLi (46mL, 2.2M in ether, 0.102mol, 10mol%) dropwise under stirring, and add dropwise for 50min After completion, the water bath was heated to 50° C. and stirred for 6 h, then the heating was stopped, and the system was allowed to return to room temperature naturally, and slowly poured into 1 L of ice water, while stirring continuously. The layers were separated, the aqueous phase was extracted with ether (3×300 mL), the organic phases were combined, washed with 500 mL of water, and dried over anhydrous sodium sulfate. The desiccant was removed by suction filtration, and dieth...

Embodiment 3

[0061] The synthesis of embodiment 3 L-menthol

[0062] 1. Amination reaction.

[0063] Replace the 1L three-necked bottle equipped with electromagnetic stirring, reflux condenser, constant pressure dropping funnel, suction head and thermometer into a nitrogen atmosphere, and add freshly steamed myrcene (80%, 82-84 ° C / 4mmHg, 173.3g, 218mL, 1.02mol), diethylamine (140g, 200mL, 1.91mol), slowly add n-BuLi (93mL, 2.2M in ether, 0.205mol, 20mol%) dropwise under stirring, add dropwise for 50min After completion, the water bath was heated to 50° C. and stirred for 5.5 hours, then the heating was stopped, and the system was allowed to return to room temperature naturally, and slowly poured into 1 L of ice water, stirring continuously during this period. The layers were separated, the aqueous phase was extracted with ether (3×300 mL), the organic phases were combined, washed with 500 mL of water, and dried over anhydrous sodium sulfate. The desiccant was removed by suction filtra...

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

PropertyMeasurementUnit
Specific rotationaaaaaaaaaa
Login to View More

Abstract

The invention belongs to the technical field of organic synthesis, in particular to a method for synthesizing L-menthol. The method for synthesizing L-menthol takes myrcene as an initial raw material and comprises the following steps: amination reaction: diethylamine and myrcene carry out amination reaction to obtain geranylamine; isomerization reaction: the geranylamine carries out isomerization reaction under the catalytic action of chiral catalyst to obtain intermediate enamine; hydrolysis reaction: the enamine carries out hydrolysis reaction in an acidic medium to produce intermediate D-citronellal; cyclization reaction: the D-citronellal generates L-isopulegol by lewis acid catalyst and organic solvent; and hydrogenation reaction: the L-isopulegol is hydrogenated to obtain L-menthol. The method for synthesizing L-menthol has the yield of more than 90 percent, the GC purity of higher than 99.0 percent and the specific rotation of -49 degrees to -50 degrees, the raw material myrcene has wide sources and lower cost, and the whole method has simple technology, good repeatability and high yield and is quite suitable for large-scale industrialized production.

Description

Technical field [0001] The invention belongs to the technical field of organic synthesis, and specifically relates to a synthesis method of L-menthol. Background technique [0002] As a naturally occurring cyclic anthyl enol, L-menthol is one of the main components of peppermint oil and occupies a special position due to its cooling and cooling properties. L-menthol can therefore be used as a fragrance or flavoring agent and in the pharmaceutical industry. Preparation of menthol by catalytic hydrogenation of a compound with at least one double bond in the menthane carbon skeleton and substituted with oxygen in the 3-position (such as thymol) yields a mixture of 8 optically active menthols: D,L-menthol , D, L-isomenthol, D, L-neo-menthol and D, L-neo-isomenthol. These eight optically active menthols differ in sensory properties, with only L-menthol having the characteristic mint smell and the above-mentioned refreshing effects. Therefore L-menthol is the most valuable ment...

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): C07C35/12C07C29/17C07C29/56C07B53/00B01J31/02
Inventor 金鹏黄战鏖陈兆刚陈文昌张金宝张长征
Owner SHANGHAI WANXIANG FLAVORS & FRAGRANCES
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products

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

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com