Synthesis method of 2-methyl-5-sulfydryl-1,3,4-thiadiazole

A synthetic method, thiadiazole technology, applied in the field of medicine, can solve the problems of high potassium hydroxide content, high cost, troublesome drying process, etc., and achieve the effect of overcoming long production cycle, reducing raw material cost, and shortening production cycle

Inactive Publication Date: 2011-10-19
SHANDONG JINING YUXIN FINE MATERIALS
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  • Abstract
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Problems solved by technology

Yet the weak point that said technique exists is: 1, after ethyl acetate, hydrazine hydrate reflux reaction, need depressurization to remove ethanol and water, not only consume energy but also time-consu

Method used

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  • Synthesis method of 2-methyl-5-sulfydryl-1,3,4-thiadiazole
  • Synthesis method of 2-methyl-5-sulfydryl-1,3,4-thiadiazole

Examples

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Embodiment 1

[0021] Take 112.0g of hydrazine hydrate with a mass percentage of 80%, and put 156.0g of ethyl acetate in a four-neck flask, stir, and heat to reflux for 8 hours. Below ℃, pour 370.0g of liquid ammonia, add 104.0ml of carbon disulfide dropwise, the dropping temperature does not exceed 40℃, react at a temperature of 35℃~45℃ for 4hrs, cool down to below 5℃, filter with suction, wash with ice ethanol, and obtain 242.0g Ammonium salt——N-acetylhydrazino ammonium dithioformate; take 512.0ml of concentrated sulfuric acid and cool it down to 0°C, then add the above-mentioned 242.0g of ammonium salt in batches, after the addition, stir for 2 hours to obtain feed liquid I; take 2500ml Ice water, slowly pour the material liquid I into it so that the temperature does not exceed 10 ° C, stir, the product precipitates, and filter to obtain 165.0 g of the crude product of thiadiazole; then the crude product is conventionally purified and vacuum-dried to obtain 2-formazol 145.0 g of 5-mercapt...

Embodiment 2

[0023] Take 112.0g of hydrazine hydrate with a mass percentage of 80%, and put 156.0g of ethyl acetate in a four-necked flask, stir, and heat to reflux for 8 hours. After the reflux is completed, cool down to 25°C, add 95.0g of methanol, and continue to cool down to below 0°C. Pass in 368.0g of liquid ammonia, add 105.0ml of carbon disulfide dropwise at 0°C to 38°C, after the dropwise addition, stir and react at 35°C to 45°C for 4 hours, cool down to 2°C, filter with suction, wash with cold methanol twice, Ammonium salt——243.5 g of ammonium N-acetylhydrazinodithioformate was obtained.

[0024] The remaining steps were the same as in Example 1 to obtain 146.8 g of finished 2-methyl-5-mercapto-1,3,4-thiadiazole.

Embodiment 3

[0026] The solvent used was 100.0 g of a mixture of methanol and ethanol in an equal volume ratio, and the rest of the raw materials and reaction conditions were the same as in Example 2 to obtain 242.8 g of ammonium salt—N-acetylhydrazinodithioformate.

[0027] The rest of the steps were the same as in Example 1 to obtain 146.2 g of finished 2-methyl-5-mercapto-1,3,4-thiadiazole.

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Abstract

The invention discloses a synthesis method of 2-methyl-5-sulfydryl-1,3,4-thiadiazole. On the basis of an original process, potassium hydroxide in the original process is replaced with liquid ammonia to synthesize an intermediate N-acetylhydrazine ammonium thiocarbamate (ammonium salt); and the drying is not needed for the intermediate; and ring closure and hydrolysis are further carried out on the intermediate in concentrated sulfuric acid; and the intermediate is purified to obtain a target product. In the invention, because the synthetic process of the key intermediate 2-methyl-5-sulfydryl-1,3,4-thiadiazole of cefazolin sodium is modified, the production period is reduced, the raw material cost is reduced, the operation is simplified, the yield of the product is increased and shortcomings of longer production period and high cost in the original technology are also effectively overcome.

Description

technical field [0001] The invention relates to an improved synthesis process of 2-methyl-5-mercapto-1,3,4-thiadiazole, which belongs to the technical fields of medicine and chemical industry. Background technique [0002] 2-Methyl-5-mercapto-1,3,4-thiadiazole is a white crystalline powder, which is the main intermediate in the synthesis of antibiotic drug cefazolin sodium, and has important industrial and medical value. [0003] The synthesis technique of existing 2-methyl-5-mercapto-1,3,4-thiadiazole mainly adopts ethyl acetate, hydrazine hydrate, methyl alcohol, potassium hydroxide, carbon disulfide, concentrated sulfuric acid etc. as raw material, by ethyl acetate It can be obtained by hydrazination, addition, cyclization and hydrolysis. The specific method is to heat ethyl acetate and hydrazine hydrate to reflux, remove ethanol and water under reduced pressure, and obtain acetylhydrazide. After cooling down, add potassium hydroxide methanol solution, add carbon disulfi...

Claims

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Application Information

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IPC IPC(8): C07D285/125
Inventor 张恒发王明刚
Owner SHANDONG JINING YUXIN FINE MATERIALS
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