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Method for synthesizing ethyl 4-methylthiazole-5-formate employing single step

A technology of methylthiazole and ethyl formate, applied in the field of synthesis of cefditoren axetil intermediates, can solve the problems of many operation steps, large environmental pollution, large amount of three wastes, etc. less effect

Active Publication Date: 2014-05-07
SHANDONG HUIHAI PHARMA & CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0009] The purpose of the present invention is to provide a method for synthesizing ethyl 4-methylthiazole-5-carboxylate in one step, which overcomes the problems of many operating steps, large amount of three wastes, and large environmental pollution in the prior art.

Method used

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  • Method for synthesizing ethyl 4-methylthiazole-5-formate employing single step

Examples

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Effect test

Embodiment 1

[0022] Add 164.5g (1mol) of ethyl 2-chloroacetoacetate and 87.5g (1.15mol) of ammonium thiocyanate to the reaction kettle, start stirring, raise the temperature to 160°C, and keep it warm for 5 hours at 160-165°C. After the reaction is completed Add 150 g of water, stir, filter, and air-dry naturally to obtain 158 g of light yellow ethyl 4-methylthiazole-5-carboxylate, with a yield of 92.28%.

Embodiment 2

[0024] Add 164.5g (1mol) of ethyl 2-chloroacetoacetate and 99g (1.3mol) of ammonium thiocyanate to the reaction kettle, start stirring, raise the temperature to 170°C, and keep it warm for 3 hours at 170-175°C. After the reaction is completed, add 130 g of water was stirred, filtered, and air-dried to obtain 144 g of pale yellow ethyl 4-methylthiazole-5-carboxylate, with a yield of 84.10%.

Embodiment 3

[0026] Add 164.5g (1mol) of ethyl 2-chloroacetoacetate and 80g (1.05mol) of ammonium thiocyanate to the reaction kettle, start stirring, raise the temperature to 130°C, and keep it warm for 6 hours at 130-135°C. After the reaction is completed, add 160 g of water was stirred, filtered, and air-dried to obtain 150 g of pale yellow ethyl 4-methylthiazole-5-carboxylate, with a yield of 87.61%.

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Abstract

The invention discloses a method for synthesizing ethyl 4-methylthiazole-5-formate employing a single step. The method comprises the following steps: reacting at 100-180 DEG C for 2-6 hours after mixing 2-chloroacetoacetic acid ethyl ester and ammonium thiocyanate; adding water to dissolve generated ammonium chloride after reaction is finished, and then filtering and drying, so as to obtain ethyl 4-methylthiazole-5-formate, wherein the molar ratio of 2-chloroacetoacetic acid ethyl ester to ammonium thiocyanate is 1:1.01 to 1:1.5. Compared with the prior art, the method has the characteristics as follows: 1, no solvent is used in a reaction process, 2 the method adopts single step synthesis, and is fewer in steps and simple and convenient to operate, and 3, the poisonous and harmful or flammable and combustible raw materials are not used, and the pressure for environmental protection is greatly reduced.

Description

technical field [0001] The present invention relates to a kind of synthetic method of cefditoren pivoxil intermediate, more specifically a kind of method of synthetic 4-methylthiazole-5-ethyl carboxylate. Background technique [0002] Ethyl 4-methylthiazole-5-carboxylate is a light yellow to white crystal with a melting point of 27-28 o C, mainly used in the synthesis of cefditoren pivoxil. [0003] The method of producing 4-methylthiazole-5-ethyl carboxylate both at home and abroad is mainly carried out according to the following two routes at present: [0004] Route 1 is to react ethyl 2-chloroacetoacetate and thiourea in ethanol to generate ethyl 2-amino-4-methylthiazole-5-carboxylate, and then carry out diazotization reaction to obtain 4-methylthiazole- Ethyl 5-formate (such as CN101921268, Tetrahedron, 69 (22) 4436-4444; 2013, Bioorganic & Medicinal Chemistry Letters, 18 (23) 6231-6235; 2008, but the yield of this route is not high when diazotization , and phosphorus...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D277/56
CPCC07D277/56
Inventor 牟应科张忠政张世凤侯旭会
Owner SHANDONG HUIHAI PHARMA & CHEM
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