Method for preparing heterocyclic compounds of methyl mercapto under ionic liquid catalysis

A technology of heterocyclic compounds and ionic liquids, applied in chemical instruments and methods, organic compounds/hydrides/coordination complex catalysts, chemical/physical processes, etc., can solve problems that no one has raised, and achieve simple and easy operation The effect of actual production and high product yield

Inactive Publication Date: 2009-08-26
DONGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Patent CN01808303.X shows that DMC can be used for N-methylation on nitrogen-containing heterocyclic rings, but no one proposes to use DMC in ionic liquids to carry out methylation reactions on sulfhydryl groups on heterocyclic compounds

Method used

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  • Method for preparing heterocyclic compounds of methyl mercapto under ionic liquid catalysis
  • Method for preparing heterocyclic compounds of methyl mercapto under ionic liquid catalysis
  • Method for preparing heterocyclic compounds of methyl mercapto under ionic liquid catalysis

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Preparation of 2-methylthiopyrimidine

[0024] Dissolve 2-mercaptopyrimidine (5.6g, 0.05mol) in 1-butyl-3-methylimidazole chloride (3.5g, 0.02mol), add dimethyl carbonate (5.4g, 0.06mol), and heat up under stirring to 90-130°C, react for 3-5 hours, and monitor by TLC or HPLC. After the reaction was completed, the product was cooled down to room temperature, extracted with ethyl acetate (10-30 ml), concentrated under reduced pressure, and the solvent was recovered to obtain the product as a colorless oil with a content of 97.6%. Add 2-mercaptopyrimidine and dimethyl carbonate to the ionic liquid, react under the same conditions, and cycle 5 times, the reaction results are shown in the following table:

[0025]

Embodiment 2

[0027] Preparation of 2-Methylthiobenzoxazole

[0028] Dissolve 2-mercaptobenzoxazole (12.1g, 0.08mol) in 1-butyl-3-methylimidazole chloride (7.0g, 0.04mol), add dimethyl carbonate (8.1g, 0.09mol), Heat up to 90-130°C with stirring, react for 2-4 hours, and monitor by TLC or HPLC. After the reaction was completed, it was lowered to room temperature, the product was extracted with ethyl acetate (10-30 ml), concentrated under reduced pressure, and the solvent was recovered. The product was vacuum-dried to obtain 10.0 g with a content of 95.2%. Yield 75.6%.

Embodiment 3

[0030] Preparation of 2-Methylthiobenzothiazole

[0031] Dissolve 2-mercaptobenzothiazole (16.7g, 0.1mol) in 1-butyl-3-methylimidazole chloride (10.5g, 0.06mol), add dimethyl carbonate (10.8g, 0.12mol), and stir Lower the temperature to 90-130°C, react for 2-4 hours, and monitor by TLC or HPLC. After the reaction was completed, it was lowered to room temperature, the product was extracted with ethyl acetate (10-30 ml), concentrated under reduced pressure, and the solvent was recovered. The product was vacuum-dried to obtain 14.9 g with a content of 95.0%. Yield 82.2%.

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Abstract

The invention relates to a method for preparing heterocyclic compounds of methyl mercapto under ionic liquid catalysis, including the followings: (1) mercapto heterocyclic compound and methyl carbonate with the mole ratio of 1: 1.2 to 2 are added to ionic liquid, and are heated to the temperature of 50 to 150 DEG C while stirring during the reaction of 0.5 to 15 hours; (2) after reaction, the temperature is decreased to room temperature to extract products, and the solvent is recycled after vacuum concentration, thus obtaining the compound. The method has the advantages of easy, simple and safe operation as well as obviously improved substrate conversion and product selectivity, and the methyl carbonate used as methylating agent and the ionic liquid used as solvent are environmentally friendly; and simultaneously the ionic liquid is easy to recycle and can be in cycle use.

Description

technical field [0001] The invention belongs to the field of preparation of methylthio heterocyclic compounds, in particular to a method for preparing methylthio heterocyclic compounds under ionic liquid catalysis. Background technique [0002] Methylthio heterocyclic compounds are an important class of chemical intermediates. For example, 2-methylthiobenzoxazole and 2-methylthiobenzothiazole have certain biological activities, and 4,6-disubstituted-2-methylthiopyrimidine is a synthetic plant growth regulator, herbicide, fungicide important intermediates for pharmaceuticals and pharmaceutical products. The synthesis method of this kind of compound generally uses the heterocyclic compound containing mercapto group as the substrate to carry out the methylation reaction, and the methylation reagent used is usually methyl iodide or dimethyl sulfate. However, methyl iodide and dimethyl sulfate are highly toxic, and methyl iodide is expensive, and these reagents have serious hid...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D239/38C07D239/56C07D263/58C07D277/74C07D235/28B01J31/02B01J31/04
Inventor 朱利民谢建刚李树白权静郑妍
Owner DONGHUA UNIV
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