Method for synthesizing pyridinecarbaldehydes compound with direct oxidization method

Abstract

The invention refers to a method for synthesizing pyridinecarbaldehydes compound with direct oxidization method, comprising the following specific steps: synthesizing catalyst, and selectively catalyzing and oxidizing methyl pyridine, by using catalytic synthesis technology and synthesis method of catalyst that a series of methyl pyridines at different substitutional positions are directly oxidized to synthesize pyridinecarbaldehyde; by using homogeneous phase complexing catalytic process, directly catalyzing and oxidizing material methyl pyridine or dimethyl pyridine at normal pressure to synthesize corresponding methyl substituted pyridinecarbaldehydes product with high catalytic efficiency, product conversion rate and product yield; the reaction conditions are simple and convenient; and the method is suitable for industrial production in large scale.

Description

【Technical field】 [0001] The invention relates to the technical field of fine chemicals, in particular to a method for synthesizing pyridine formaldehyde compounds by a direct oxidation method. 【Background technique】 [0002] 2-Pyridinecarbaldehyde is a key intermediate for laxatives such as bysacodyl and organophosphorus antidotes, and 4-pyridinecarbaldehyde is a key intermediate for drugs such as donepezil hydrochloride. For a long time, the synthesis efficiency, synthesis method and synthesis technique of these compounds have attracted the attention of many researchers. [0003] As far as 2-pyridinecarbaldehyde is concerned, in 2005, Huang Shengtang et al proposed to use hydrogen peroxide to oxidize 2-picoline synthesis route (Chemical Reagents, 2005, 27, (1), 58), the process route uses readily available raw materials and moderate cost , easy for industrial production and processing. However, due to the high-temperature hydrazinolysis process used in the process route,...

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Problems solved by technology

(Journal of Chemical Engineering of Colleges and Universities 2002, 16, (4), 436); this process has the characteristics of 80-90% selectivity, easy product purification, low oxygen consumption, and less power consumption. However, this process has the advantages of high yield Low, equipment investment is too large and other shortcomings

[0007] Zuo Jinfu et al. gave a more convenient synthetic technology route (Qilu Pharmaceutical, 2004, 23, (2), 40), this process route is to synthesize pyridinemethanol by rearrangement of picoline nitrogen oxide compound, and then further oxidize, Rearrangement to obtain pyridine formaldehyde products; this process has the advantages of easy-to-obtain raw materials, cheap synthesis, simple production conditions, and easy product processing, but this process has many reaction steps, low production yield and other defects, and the cost of industrial production is still high

[0008] In 2007, Guo Zhe and others proposed a new process for the synthesis of 2-pyridine formaldehyde using 2-cyanopyridine (Chinese Journal of Pharmaceutical Industry 2007, 38, (7), 480), but the raw material cost of 2-cyanopyridine is relatively high , industrial production costs are still difficult to effectively control

[0009] Shen Dadong et al. have given the chlorination method to produce synthetic 2-pyridine formaldehyde technology (Chinese Journal of Pharmaceutical Industry 2006, 37, (7), 448). This production process has high production efficiency and is easy to operate, but the process route chlorination process is inevitable There will be trichloromethylpyridine by-products, so the overall cost of production is still high

[0010] The direct use of chlorine gas to catalyze 2-picoline to synthesize 2-dichloromethylpyridine has also attracted people's attention. Similar compounds 2,3-dichloro-5-trifluoromethylpyridine (patent CN101062915) and 2,3-dichloro -5-trichloromethylpyridine (patent: CN200710042786) provides different types of chlorination technology; wherein, the patent (CN200810062907.5) provides the use of chlorine to synthesize 6-chloromethylpyridine intermediates - 2-trichloromethylpyridine technology; however, this technology suffers from the technical problem of using highly toxic chlorine gas

[0011] Synthetic technologies such as 4-pyridinecarbaldehyde and 2,6-pyridinecarbaldehyde also have a variety of technical process routes, but in general, almost all of these technical routes have problems such as many synthesis steps and harsh production conditions