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ChemicalBook CAS DataBase List Methimazole
60-56-0

Methimazole synthesis

5synthesis methods
Methimazole, 1-methyl-2-imidazolthiol (25.2.5), is synthesized by reacting aminoacetic aldehyde diethylacetal with methylisothiocyanate and subsequent hydrolysis of the acetal group of the resulting disubstituted urea derivative 25.2.4 by a solution of sulfuric acid, during which a simultaneous cyclization reaction takes place, forming the imidazole ring of the desired methimazole .

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Yield:60-56-0 150 kg

Reaction Conditions:

with hydrogenchloride in water at 20 - 30;Large scale;

Steps:

1.c

in 5 of adding the reactor 410 kg methylamino acetaldehyde diethyl acetal, 270 kg of potassium thiocyanate and 500 kg of purified water, stirring the mixture at room temperature after completely dissolved, to the 5 of the pre-prepared reaction in the cauldron adds by drops 1mol/L dilute hydrochloric acid 1000 kg, control of the temperature of the reaction solution in the 30 °C left and right.After the reaction, the reaction liquid water is removed by reduced pressure distillation, the resulting solid with ethyl acetate is dissolved again, after the undissolved substances, ethyl acetate is removed by reduced pressure distillation. The resulting solid is dissolved in purified water, adjust the pH to 1, the cooling crystallization to obtain the purity is greater than 99% of the product, vacuum drying to obtain 2-mercapto-1-methyl imidazole final product 150 kg, yield of 47.2%.

References:

CN103214421,2016,B Location in patent:Paragraph 0024; 0025

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