638-07-3Relevant articles and documents
Preparation method of ethyl 4-chloroacetoacetate
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Paragraph 0041; 0045-0051; 0055-0061; 0065-0070, (2021/08/06)
The invention discloses a preparation method of ethyl 4-chloroacetoacetate, which specifically comprises the following steps of: (1) chlorination: cooling dichloromethane for the first time, then adding acetyl ketene for cooling for the second time, then introducing chlorine gas, and keeping the temperature; (2) esterification: dropwise adding absolute ethyl alcohol, and keeping the temperature; (3) desolvation and deacidification: heating and distilling to remove dichloromethane and hydrogen chloride; and (4) rectification: rectifying and purifying to obtain the product. Acetyl ketene is used as a raw material, the raw material is low in cost and easy to obtain, the synthesis steps are simple, and the production cost is reduced; by optimizing the ratio of process materials, the selectivity of the product ethyl 4-chloroacetoacetate is improved, and the yield is increased; and through high-vacuum low-temperature distillation, the decomposition of the heat-sensitive product ethyl 4-chloroacetoacetate is effectively prevented, and the yield and the product quality are improved.
Synthetic method for ethyl 2-(2-aminothiazol-4-yl)-2-methoxyiminoacetate
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Paragraph 0016, (2020/01/12)
The invention discloses a synthetic method for ethyl 2-(2-aminothiazol-4-yl)-2-methoxyiminoacetate. The method is characterized by comprising the following steps: a, performing chlorination on diketene, and performing alcoholysis to synthesize ethyl 4-chloroacetoacetate; b, performing oximation on the ethyl 4-chloroacetoacetate to synthesize ethyl 4-chloro-2-(hydroxyimino)-3-oxobutanoate; c, performing a reaction on the ethyl 4-chloro-2-(hydroxyimino)-3-oxobutanoate and thiourea to synthesize ethyl 2-(2-aminothiazol-4-yl)-2-hydroxyiminoacetate; and d, performing hydrocarbonylation on the ethyl2-(2-aminothiazol-4-yl)-2-hydroxyiminoacetate to synthesize the ethyl 2-(2-aminothiazol-4-yl)-2-methoxyiminoacetate. The method has the following advantages: 1, the chlorination reaction in the stepa is a continuous reaction, and has a fast reaction speed and no accumulation of a large amount of dangerous materials, so that the danger is small; 2, the costs of equipment are lower, the equipmentis conventional organic synthesis equipment, no expensive and special equipment is needed, so that the equipment is easy to copy, and the production efficiency is improved; and 3, the diketene is directly used as a raw material, the raw material cost is low, the synthetic steps are simple to operate, so that the method facilitates reducing the production costs of the ethyl 2-(2-aminothiazol-4-yl)-2-methoxyiminoacetate.
Method for synthesizing oxiracetam intermediate 4-ethyl chloroacetoacetate
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Paragraph 0035-0040, (2019/03/28)
The invention discloses a method for synthesizing oxiracetam intermediate 4-ethyl chloroacetoacetate and belongs to the field of pharmacy. The method is characterized in that chloroacetate and ethyl acetate react under the action of a catalyst to obtain the 4-ethyl chloroacetoacetate. The reaction process is: (1) evenly mixing the ethyl acetate, the catalyst and a solvent A, introducing protectivegas, controlling the pressure to be 0.3-0.5 Mpa, controlling the temperature to be 110-135 DEG C, adding a solution prepared from chloroacetate and a solvent B dropwise, controlling the addition timeto be 15-25 min, after chloroacetate and the solvent B are added, increasing the reaction temperature to 145-160 DEG C, increasing the pressure to 0.8-1 Mpa, continuing the reaction for 15-25 h, andthen ending the reaction; and (2) after a system is cooled, filtering the system to remove solid, adding filtrate to water with the volume being 3-5 times that of the filtrate, using a solvent C for extraction, and after an extract is dried with a drying agent, concentrating and evaporating the solvents to obtain a product. The method for synthesizing the oxiracetam intermediate 4-ethyl chloroacetoacetate has the advantages of relatively short steps, low process cost and few side effects.