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Wethod for preparation acetylacetic ester

An acetoacetate, cyclic technology, applied in the field of preparation of acetoacetate, can solve the problems of side reaction by-products, drug pollution, etc.

Inactive Publication Date: 2004-03-24
DAICEL CHEM IND LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, general preparation methods often lead to drug contamination due to impurities, because these methods often cause side reactions and thus produce a large amount of by-products

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027]In the separatory bottle equipped with stirrer, dropping funnel, condenser and thermometer, charge 58g p-nitrobenzyl alcohol, 295g toluene, 0.32g N-methylpyrrolidine. The mixture was stirred continuously at 30°C, and 33 g of diketene was added dropwise to the reaction for at least 3 hours. After the dropwise addition, it was matured at room temperature for 20 hours. The reaction mixture was washed successively with a 0.2% by weight aqueous hydrochloric acid solution and ion-exchanged water, the organic layer was dehydrated, and a toluene solution product of p-nitrobenzyl acetoacetate was thereby produced. After HPLC analysis, this product showed that except the toluene solvent, it contained 99.07% by weight (87g, a yield of 97%) of p-nitrobenzyl acetoacetate (NBAA) and 0.06% by weight eluting through the NBAA peak impurity (52mg).

[0028] The results of HPLC analysis are shown in Table 1.

Embodiment 2

[0030] In the present embodiment, except for the catalyst, other operating procedures are the same as in Example 1, and the toluene solvent product of p-nitrobenzyl acetoacetate is obtained, and the catalyst is the same 3-methyl Pyridine instead of N-methylpyrrolidine. Its product HPLC analysis result is shown in table 1.

Embodiment 3

[0032] In this embodiment, except for the catalyst, other operating procedures are the same as in Example 1, and the toluene solvent product of p-nitrobenzyl acetoacetate is obtained. The catalyst is to replace N- Methylpyrrolidine. Its product HPLC analysis result is shown in table 1.

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PUM

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Abstract

Nitrogen-containing cyclic organic bases are used as catalysts in a method for the production of acetoacetic acid esters by reacting diketene with a benzyl alcohol in presence of a solvent.

Description

technical field [0001] The present invention relates to a kind of method for preparing acetoacetate, more specifically, relate to the method for preparing benzyl acetoacetate. These compounds can be used as pharmaceutical intermediates and intermediate substances of other fine chemicals. Background technique [0002] Benzyl acetoacetate is usually used as a pharmaceutical intermediate. For example, p-nitrobenzyl acetoacetate is used as an intermediate of carbapenem antibiotics in the field of pharmaceutical preparations. The conventional method for preparing p-nitrobenzyl acetoacetate includes, for example: (a) by the catalysis of triethylamine, p-nitrobenzyl alcohol is reacted with diketene in toluene (Japanese Patent Application No. 3-197459 bulletin); (b) by the catalysis of p-toluenesulfonic acid, p-nitrobenzyl alcohol is reacted with diketene in benzene (US Patent 3,014,838); (c) p-nitrobenzyl alcohol is reacted with acetoacetic acid Reaction of ethyl ester in toluen...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07B61/00C07C67/46C07C69/72C07C205/42
CPCC07C67/46C07C201/12
Inventor 渡边仁志尾崎亨滨谷武
Owner DAICEL CHEM IND LTD
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