Process for microwave synthesis of 1,3-disubstituted imidazole-2-thioketone

A disubstituted imidazole and microwave synthesis technology, applied in 1 field, can solve the problems of methanol poisoning, long reaction time, etc., and achieve the effects of reducing side reactions, shortening reaction time, and reducing microwave radiation power

Inactive Publication Date: 2006-01-18
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Arduengo applied for a patent (USP5,104,993) for the synthesis of 1,3-dialkylimidazolium-2-thiones in 1992. This synthesis method is in the presence of potassium carbonate, with 1,3-alkylimidazolium salt and Sulfur is used as a raw material to synthesize 1,3-dialkylimidazole-2-thione, the reaction time is long (24-48 hours) and anhydrous is required, and methanol is highly toxic

Method used

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  • Process for microwave synthesis of 1,3-disubstituted imidazole-2-thioketone
  • Process for microwave synthesis of 1,3-disubstituted imidazole-2-thioketone
  • Process for microwave synthesis of 1,3-disubstituted imidazole-2-thioketone

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0014] Example 1 Synthesis of 1,3 dimethylimidazole-2-thione

[0015] Mix 10 mmoles of 1,3 dimethylimidazole chloride and 11 mmoles of potassium thiocyanate uniformly in a 20 ml one-mouth bottle, react under 50W power microwave radiation for 5 minutes, cool naturally to room temperature, and use the reaction mixture with After 50 ml of ethyl acetate-water (volume ratio 1:1) was dissolved, put it into a separatory funnel, separate the organic phase, dry it with anhydrous potassium sulfate for 2 hours, concentrate, and use silica gel column chromatography (eluent (n-hexane: ethyl acetate = 2:1) to obtain 1.02 g of 1,3-dimethylimidazole-2-thione with a yield of 80%.

[0016]

[0017] 1 HNMR (500MHz, CDCl 3 ): δ=3.60(s, 6H), 6.71(s, 2H);

[0018] 13 CNMR (500MHz, CDCl 3 ): δ=34.56, 117.55, 162.12;

[0019] IR (cm -1 )2957, 1445, 1230, 1045;

[0020] MS([M+H] + ): 128.8;

Embodiment 2

[0021] Example 2 Synthesis of 1-butyl-3-methylimidazole-2-thione

[0022] The reaction steps are the same as in Example 1, except that 1-butyl-3-methylimidazole bromide is used as the raw material, and the post-treatment operation is the same as in Example 1, and the yield of the product obtained is 75%.

[0023]

[0024] 1 HNMR (500MHz, CDCl 3 ): δ=0.96(t, 3H), 1.38(m, 2H), 1.75(m, 2H), 3.61(s, 3H), 4.03(t, 2H), 6.71(dd, 2H);

[0025] 13 CNMR (500MHz, CDCl 3 ): 13.74, 19.82, 31.02, 35.10, 47.83, 116.63, 117.74, 161.72

[0026] IR (cm -1 ) 2958, 2933, 1568, 1462, 1414;

[0027] MS([M+H] + ): 170.8;

Embodiment 3

[0028] Example 3 Synthesis of 1-butyl-3-methylimidazole-2-thione

[0029] The reaction steps are the same as in Example 2, except that the reaction is carried out under 70W power microwave radiation for 2 minutes, and the post-treatment operation is the same as in Example 1, and the yield of the product obtained is 80%.

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Abstract

The present invention discloses microwave synthesis process of 1, 3-disubstituting imidazole-2-thione. Under irradiation of microwave, 1, 3-disubstituting imidazole-onium salt and potassium thiocyanate in the equivalent ratio of 1 to 1-2 react to synthesize 1, 3-disubstituting imidazole-2-thione. The microwave radiation power is 50-200 W and microwave radiation reaction period is 2-10 min. The present invention has the advantages of short reaction period, less side reactions, high reaction yield, lower microwave radiation power, no need of dewatering, simple post-treatment, no need of organic solvent, no pollution, etc.

Description

technical field [0001] The invention relates to a microwave synthesis method of 1,3-disubstituted imidazole-2-thione. Background technique [0002] Imidazole-2-thione is a class of important compounds widely used in medicine and chemical industry, such as 1-methylimidazole-2-thione (Methimazole  ) can be used to treat thyroid secretion disorders; some imidazole-2-thiones can also be used to treat arthritis. In addition, imidazole thione has antioxidant and flame retardant functions, such as benzimidazole thione can be used as rubber antioxidant; 1,3-dialkylimidazole-2-thione can be used as a catalyst for the synthesis of epoxy resin and can significantly improve properties of the resin. Arduengo applied for a patent (USP5,104,993) for the synthesis of 1,3-dialkylimidazolium-2-thiones in 1992. This synthesis method is in the presence of potassium carbonate, with 1,3-alkylimidazolium salt and Sulfur is used as a raw material to synthesize 1,3-dialkylimidazole-2-thione, the...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D233/30
Inventor 雷鸣王彦广
Owner ZHEJIANG UNIV
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