Prepn process of 4-bromo-3,5-dimethoxy benzaldehyde

A technology of dimethoxybenzaldehyde and production process, applied in the field of preparing 4-bromo-3, can solve the problems of complex production process flow, low product yield and the like, and achieve the effect of shortening the process flow and improving the yield

Inactive Publication Date: 2002-07-10
昆山虹祺药业有限责任公司
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Problems solved by technology

[0003] The present invention solves the problems of complex production process

Method used

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Examples

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Embodiment

[0011] Embodiment: 1. Get 53.6 grams of p-aminotoluene, dissolve it in 150 milliliters of methanol, add 168.0 grams of bromine dropwise under the condition of 15 degrees Celsius to 20 degrees Celsius, stir the reaction (15 degrees Celsius to 20 degrees Celsius) for 3 hours, decompress, and Methanol was evaporated to dryness to obtain product a, namely: 4-amino-3,5-dibromotoluene.

[0012] ②. Take 53.0 grams of product a, dissolve it in 200 ml of dimethylformamide, add 40 grams of cetyltrimethylammonium bromide at the same time, and heat to about 80 degrees Celsius, add dropwise 116.0 grams of sodium methoxide solution, and stir React for 3 hours, cool, filter, wash the filter cake with water, and dry to obtain product b, namely: 4-amino-3,5-dimethoxytoluene.

[0013] ③. Dissolve 33.5 grams of product b in 70.5 grams of hydrobromic acid, cool to 0-5 degrees Celsius in an ice-salt bath, and, under stirring, add cold sodium nitrite solution dropwise quickly and slowly (17.5 grams...

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PUM

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Abstract

The preparation of 4-bromo-3,5-demethoxy benzaldehyde, as the main intermediate for preparing brodimoprim, includes the steps of: the substitution reaction between amino methylbenzene and bromine on benzene ring in solvent A and the decompressing evaporation of solvent A; the alkoxylation between the product of the fore step and added sodium methoxide in solvent B and in the presence of catalyst, filtering, water washing of the filtering cake to eliminate solvent B and drying; and diazotization of the product, Sandmeyer reaction, photobromization and hydrolysis to obtain 4-bromo-3,5-demethoxy benzaldehyde. It has short technological process and high product yield.

Description

(1) Technical field [0001] The invention relates to a new production process for preparing 4-bromo-3,5-dimethoxybenzaldehyde. (2) Background technology [0002] 4-Bromo-3,5-dimethoxybenzaldehyde is the main intermediate for the preparation of brodimoprim, which is a dihydrofolate reductase inhibitor, used for various respiratory infections, bacterial Gastroenteritis, urinary tract infection and typhoid etc. It is a new alternative to trimethoprim (TMP), an antibacterial synergist widely used in clinical practice. (3) Contents of the invention [0003] The present invention aims to solve the problems of complex production process and low product yield in the current preparation of 4-bromo-3,5-dimethoxybenzaldehyde. The adopted technical scheme is realized through the following steps: ①. Substitution reaction on the benzene ring occurs between p-aminotoluene and bromine in solvent A, and solvent A is evaporated to dryness under reduced pressure; ②. The above-mentioned prod...

Claims

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Application Information

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IPC IPC(8): C07C45/00C07C47/575
Inventor 王皆胜王斌
Owner 昆山虹祺药业有限责任公司
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