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Synthetic method for 2-acetyl thiazole

A technology of acetyl thiazole and synthesis method, applied in directions such as organic chemistry, can solve problems such as high consumption of raw materials, uneconomical economy, complicated operation process, etc., and achieve the effects of improving preparation process, optimizing reaction temperature, and fast reaction rate

Inactive Publication Date: 2016-02-24
JINAN ENLIGHTEN BIOTECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The operation process of this traditional method is very cumbersome and consumes a lot of raw materials. Therefore, although the yield is high, it is not economical.

Method used

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  • Synthetic method for 2-acetyl thiazole

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] 1) Preparation of 2-aminothiazole

[0047] Add 300ml of toluene, 30g of thiourea and 40g of chloroacetaldehyde into a 500ml three-necked round-bottomed flask, stir, maintain the temperature at 60°C, keep the temperature for 1.5h, cool, add 20% sodium hydroxide solution for neutralization, adjust the pH to 7, separate The organic layer was distilled under reduced pressure to obtain 2-aminothiazole. The melting point of 2-aminothiazole was 92-93° C., the mass was 27.6 g, and the yield was 69.9%.

[0048] 2) Preparation of 2-bromothiazole

[0049] Dissolve 0.25mol of 2-aminothiazole in 150ml of 45% sulfuric acid in a 500ml reaction flask, stir to partially dissolve the 2-aminothiazole and cool to 2°C, add 50ml of 65% concentrated nitric acid dropwise, and keep the internal temperature below 10°C. Then slowly add 50ml of 5mol / l sodium nitrite aqueous solution dropwise, after the addition is complete, continue to stir for 1h, and control the temperature below 7°C. Use a dr...

Embodiment 2

[0053] 1) Preparation of 2-aminothiazole

[0054] Add 300ml of toluene, 30g of thiourea and 43g of chloroacetaldehyde into a 500ml three-neck round bottom flask, under stirring, maintain the temperature at 70°C, keep the temperature for 2.5h, cool, add 20% sodium hydroxide solution for neutralization, adjust the pH to 7, Separate the organic layer and distill under reduced pressure to obtain 2-aminothiazole, the melting point of 2-aminothiazole is 92-93°C, the mass is 31.5g, and the yield is 79.8%.

[0055] 2) Preparation of 2-bromothiazole

[0056] Dissolve 0.25mol of 2-aminothiazole in 150ml of 45% sulfuric acid in a 500ml reaction flask, stir to partially dissolve the 2-aminothiazole and cool to 4°C, add 50ml of 65% concentrated nitric acid dropwise, and keep the internal temperature below 10°C. After that, 50 mL of 5 mol / L sodium nitrite aqueous solution was slowly added dropwise. After the addition was completed, the stirring was continued for 1 h, and the temperature wa...

Embodiment 3

[0060] 1) Preparation of 2-aminothiazole

[0061] Add 300ml of toluene, 30g of thiourea and 46g of chloroacetaldehyde to a 500ml three-necked round bottom flask, under stirring, maintain the temperature at 80°C, keep the temperature for 2h, cool, add 20% sodium hydroxide solution for neutralization, adjust the pH to 7, divide The organic layer was taken out, and 2-aminothiazole was obtained by distillation under reduced pressure. The melting point of 2-aminothiazole was 92-93° C., the mass was 33.9 g, and the yield was 85.9%.

[0062] 2) Preparation of 2-bromothiazole

[0063] Dissolve 0.25mol of 2-aminothiazole in 150ml of 45% sulfuric acid in a 500ml reaction flask, stir to dissolve the 2-aminothiazole and cool to 5°C, add 50ml of 65% concentrated nitric acid dropwise, and keep the internal temperature below 10°C. Then slowly add 50ml of 5mol / l sodium nitrite aqueous solution dropwise, after the addition is complete, continue to stir for 1h, and control the temperature belo...

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Abstract

The invention relates to a synthetic method for 2-acetyl thiazole. The synthetic method comprises the following steps: firstly, preparation of 2-amino thiazole is carried out, namely, toluene, thiourea and chloroacetaldehyde are mixed, a reaction is carried out with stirring at a constant temperature, and 2-amino thiazole is prepared; secondly, preparation of 2-bromo thiazole is carried out, namely, 2-amino thiazole is dissolved in sulfuric acid, cooling is carried out, a sodium nitrite aqueous solution is added drop by drop slowly at a controlled temperature after concentrated nitric acid is added drop by drop, stirring is carried out continuously, a reaction is carried out, the solution after the reaction is added in a mixed solution of sodium bromide and copper sulphate, a bromination reaction is carried out, and 2-bromo thiazole is prepared; thirdly, preparation of 2-acetyl thiazole is carried out, namely, 2-bromo thiazole is added in a butyllithium solution, stirring is carried out, then ethyl acetate is added, a reaction is carried out, and 2-acetyl thiazole is prepared. The acetylation step of 2-bromo thiazole is improved, the reaction raw material ratio and the reaction temperature are optimized, the high yield of the reaction is achieved, safe and reliable operation of the experiment is ensured effectively, and unexpected technical effects are achieved.

Description

technical field [0001] The invention belongs to the field of chemical synthesis, in particular to a method for synthesizing 2-acetylthiazole. Background technique [0002] Thiazole rings are an important class of five-membered aromatic heterocycles, containing nitrogen and sulfur heteroatoms, rich in electrons, easy to form hydrogen bonds, coordinate with metal ions, and π-π stacking, electrostatic and hydrophobic interactions, etc. Valence bond interaction, this structure endows thiazole compounds with many special properties, and has a wide range of potential applications in many fields. 2-Acetylthiazole is a food spice, which naturally exists in cooked beef, cooked pork liver, asparagus, potatoes, and rice, and has an aroma similar to nuts, rice, and popcorn. The United States has approved the use (FEMA registration number is 3328), and my country's GB2760-1996 stipulates that it is a food spice that is allowed to be used. [0003] At present, the production route of 2-...

Claims

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Application Information

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IPC IPC(8): C07D277/24
CPCC07D277/24
Inventor 李新孙斌卫洁王霄聪赵雷振臧传近自妍妍张知伟刘元武高明
Owner JINAN ENLIGHTEN BIOTECH CO LTD
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