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Method for synthesizing 2-acetyl-3-methylpyrazine

A technology of methylpyrazine and acetyl, which is applied in the field of synthesis of flavors and fragrances, can solve the problems of multiple toxic wastes, serious environmental pollution, and application restrictions, and achieve high-efficiency catalytic effects, economical and environmentally friendly synthesis processes, and mild oxidation conditions.

Inactive Publication Date: 2019-04-19
FUZHOU UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The main prominent problem of the above two methods is that the used N-bromosuccinimide or sodium dichromate are highly toxic substances, and the use of a large amount of toxic reagents can produce more toxic wastes, causing serious environmental pollution , from an economic and environmental point of view, its application is very limited

Method used

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  • Method for synthesizing 2-acetyl-3-methylpyrazine
  • Method for synthesizing 2-acetyl-3-methylpyrazine

Examples

Experimental program
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Effect test

Embodiment 1

[0021] In a 1000 ml three-necked flask, add 30.0 grams of 2-ethyl-3-methylpyrazine (content 99%), 0.82 grams of ferric chloride (n / n: 50:1), 0.92 grams of 1,10-phenanthrene Roline (n / n: 50:1), 14.8 grams of propionic acid and 145 grams of tert-butanol peroxide were stirred with a magnetic stirrer, heated to an internal temperature of 65-75°C, and the reaction was completed after 24 hours, and then distilled under reduced pressure. After rectification, 2-acetyl-3-methylpyrazine was obtained. The conversion rate of 2-ethyl-3-methylpyrazine was 48.75%, and the selectivity of 2-acetyl-3-methylpyrazine was 95.88%.

Embodiment 2

[0023] In a 1000 ml three-necked flask, add 30.0 g of 2-ethyl-3-methylpyrazine (content 99%), 1.3 g of cobalt (II) acetylacetonate (n / n: 50:1), 0.92 g of 1, 10-Phenanthroline (n / n: 50:1), 14.8 grams of acetic acid and 145 grams of tert-butanol peroxide, stirred with a magnetic stirrer, heated to an internal temperature of 65-75 °C, and the reaction was completed after 24 hours, and the pressure was reduced After distillation and rectification, 2-acetyl-3-methylpyrazine was obtained. The conversion rate of 2-ethyl-3-methylpyrazine was 40.29%, and the selectivity of 2-acetyl-3-methylpyrazine was 90.49%.

Embodiment 3

[0025] In a 1000 ml three-necked flask, add 30.0 g of 2-ethyl-3-methylpyrazine (content 99%), 1.3 g of cobalt (II) acetylacetonate (n / n: 40:1), 0.8 g of 2, 2'-bipyridine (n / n: 40:1), 14.8 grams of benzoic acid and 145 grams of tert-butanol peroxide were stirred with a magnetic stirrer, heated to an internal temperature of 30-40°C, and the reaction was terminated after 24 hours, and the Pressure distillation and rectification give 2-acetyl-3-methylpyrazine. The conversion rate of 2-ethyl-3-methylpyrazine was 37.05%, and the selectivity of 2-acetyl-3-methylpyrazine was 92.23%.

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Abstract

The invention discloses a method for generating 2-acetyl-3-methylpyrazine with 2-ethyl-3-methylpyrazine as a raw material through oxidation. According to the method, the 2-ethyl-3-methylpyrazine and tert-butyl hydroperoxide serve as raw materials, and a catalyst and a ligand are added to serve as a catalyzing system; the 2-ethyl-3-methylpyrazine and the tert-butyl hydroperoxide react under the catalytic effect, and the 2-acetyl-3-methylpyrazine is obtained through one-step oxidation. The method has the advantages that the synthesis technology is economical and environmentally friendly, products such as water and tert butyl alcohol are free of pollution, reaction conditions are mild and simple, a large amount of toxic waste generated by a traditional technology is avoided, the selectivity for the 2-acetyl-3-methylpyrazine can reach 90% or above, and the method provides a new technology for preparing the 2-acetyl-3-methylpyrazine, and has broad industrial prospects.

Description

technical field [0001] The invention relates to a chemical synthesis method, in particular to a synthesis method of flavors and fragrances. Background technique [0002] Pyrazine compounds exist along with human life, and are formed in many natural or processed foods during frying, boiling and fermentation to produce aroma, but because the content of pyrazine spices in these foods is very small, Natural extraction is not advisable, so it needs to be mass-produced by artificial synthesis. The English name of 2-acetyl-3-methylpyrazine is 2-Acetyl-3-methylpyrazine, the CAS number is 23787-80-6, and the molecular formula is C 7 h 8 N 2 O, with a molecular weight of 136.15, has woody, warm and bacony aromas, and belongs to pharmaceutical intermediates. This medicine can be used as a daily essence and a flavoring agent. As an important synthetic fragrance and fine organic chemical intermediate, 2-acetyl-3-methylpyrazine is widely used in flavors and fragrances, medicine, pesti...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D241/12
CPCC07D241/12
Inventor 王莹淑余珺郑辉东陈晶晶严仲毅
Owner FUZHOU UNIV
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