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Method for synthesizing 2-amino thizaoline

A technology for the synthesis of aminothiazolines and methods, which is applied in the field of synthesis of 2-aminothiazolines, can solve the problems of many operation steps and high energy consumption, and achieve the effects of advanced process routes, low production costs, and shortened reaction steps

Active Publication Date: 2009-04-29
山西新天源药业有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When this method is used to prepare ethanolamine hydrochloric acid, in order to remove the water in the reaction solution, it needs to be heated and distilled for dehydration. The remaining small amount of water needs to be added with toluene, and it is taken out by azeotropic water. The operation steps are many and the energy consumption is high.

Method used

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  • Method for synthesizing 2-amino thizaoline
  • Method for synthesizing 2-amino thizaoline

Examples

Experimental program
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Effect test

Embodiment 1

[0017] Preparation of 2-chloroethylamine hydrochloride

[0018] Add 250mL of chloroform and 46.5g (0.76mol) of ethanolamine into a dry reaction flask equipped with a reflux device, stirring and thermometer, start stirring, mix well, cool down to 10°C, and slowly add 121g (1.02mol) of chlorinated chlorinated The sulfone was added dropwise within 3 hours, and the temperature was raised to reflux temperature. After 15 hours of reaction, chloroform and excess thionyl chloride were distilled off, cooled slowly to precipitate crystals, continued to cool down to 5°C, filtered, and vacuum-dried to obtain 85.6g 2-Chloroethylamine hydrochloride white flaky crystals.

[0019] mp: 146.3~147.1℃ (literature value is 147.5~148℃), yield 97%, purity 99.2% (GC method), IR (KBr): υ -NH 3500cm -1 , 3116cm -1 , 1582cm -1 ; C-N 1110cm -1 .

[0020] Synthesis of 2-aminothiazoline

[0021] Dissolve 85.6g (0.74mol) of 2-chloroethylamine hydrochloride in 200mL of water, add 160g (2.10mol) of th...

Embodiment 2

[0024] Add 300mL of toluene and 46.5g (0.76mol) of ethanolamine to a dry reaction flask equipped with a reflux device, stirring and thermometer, start the stirring, make it evenly mixed, cool down to 10°C, and slowly add 119g (1mol) of thionyl chloride dropwise , the dropwise addition was completed within 3 hours, and the reflux reaction was maintained for 10 hours. The toluene and unreacted thionyl chloride were evaporated under normal pressure, and then the solvent was evaporated to dryness under reduced pressure at 60°C.

[0025] Add 200 mL of water and 165 g (2.17 mol) of thiourea to the residue in the reaction flask, heat to reflux for 20 hours, cool down to 70°C, add 40% sodium hydroxide solution to adjust the pH to 9, and extract with 200 mL of dichloromethane 2 times, and then extracted 1 time with 100mL dichloromethane, combined the extracts, dried over anhydrous sodium sulfate, concentrated, filtered, and vacuum dried to obtain 56.6g of white crystals of 2-aminothiazo...

Embodiment 3

[0027] Add 220mL of dichloromethane and 46.5g (0.76mol) of ethanolamine into a dry reaction flask equipped with a reflux device, stirring and thermometer, start stirring, mix well, cool down to 10°C, and slowly add 135g (1.13mol) of chlorine The thionyl chloride was added dropwise within 3 hours, and the reflux reaction was maintained for 12 hours, dichloromethane and thionyl chloride were evaporated under normal pressure, and distilled to dryness under reduced pressure.

[0028] Add 200 mL of water and 172 g (2.26 mol) of thiourea to the residue in the reaction flask, heat to reflux for 22 hours, cool down to 70°C, add 40% sodium hydroxide solution to adjust the pH to 9, and extract with 200 mL of dichloromethane 2 times, and then extracted 1 time with 100mL dichloromethane, combined extracts, dried over anhydrous sodium sulfate, concentrated, filtered, and vacuum-dried to obtain 57.2g of white crystals of 2-aminothiazoline, with a yield of 73.6% (relative to ethanolamine) , ...

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Abstract

The invention relates to a method for synthesizing 2-aminothiazoline, which comprises the following steps: firstly, performing chlorinated reaction between ethanolamine and thionyl chloride in an organic solvent to generate 2-chloro-ethylamine hydrochloride; and secondly, performing cyclization reaction between the 2-chloro-ethylamine hydrochloride and thiourea to generate the 2-aminothiazoline. Compared with the prior art, the method does not need introduce hydrogen chloride gas and concentrated hydrochloric acid to synthesize ethanolamine hydrochloride, thereby reducing reaction reagents and the reaction steps; besides, the process route is more advanced, environment-friendly and safer, and the cyclization yield reaches more than 70 percent.

Description

technical field [0001] The invention relates to a synthesis method of 2-aminothiazoline. Background technique [0002] 2-Aminothiazoline, the English name is 2-Aminothiazoline, its structural formula is as follows: [0003] [0004] As a pharmaceutical intermediate, the compound is mainly used in the synthesis of semi-synthetic antibiotic cefotiam and anti-leprosy drug thiazole sulfone, and at the same time, the compound is also the main component of space radiation protection agents and cosmetic sunscreens. [0005] The synthetic method of existing 2-aminothiazoline is to take ethanolamine as starting material, reacts with hydrogen chloride or hydrochloric acid to generate ethanolamine hydrochloride, then reacts with thionyl chloride to generate 2-chloroethylamine hydrochloride, finally reacts with thiocyanate Sodium acid was subjected to ring-forming reaction, which was extracted, concentrated and refined (Doherty D.G., et al J.Am.1957(79)5667). [0006] In this synth...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D277/18
Inventor 苏斌林陈万成高志伟褚丕明苏蔚康福堂
Owner 山西新天源药业有限公司
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