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Method for industrial preparation of 6-methyl-3-aminopyridazine

A technology of aminopyridazine and methyl, which is applied in the field of industrialized preparation of 6-methyl-3-aminopyridazine, can solve the problem of no effective preparation method for industrialized scale-up production, poor recycling of raw materials, and operation reaction process Complexity and other issues, to achieve the prospect of large-scale industrial formation, increase the effective synthesis yield, and simple feeding and post-processing operations

Inactive Publication Date: 2013-04-24
QUANZHOU NORMAL UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] 6-Methyl-3-aminopyridazine is a very important pharmaceutical and chemical intermediate, but so far there is no effective method for the industrial scale-up production of this product
[0010] (b) The temperature in the second step is high, and the reaction pressure is also high, so the requirements for the reaction equipment are high, the preparation cost is high, and the equipment consumption is large;
[0011] (c) The reaction yield is low, the raw materials are not well recycled, resulting in large waste, and the operation reaction process is complicated at the same time

Method used

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  • Method for industrial preparation of 6-methyl-3-aminopyridazine

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preparation example Construction

[0021] The invention relates to an industrial preparation method of 6-methyl-3-aminopyridazine, which uses 6-methyl-3-chloropyridazine as a raw material, and carries out ammoniation reaction with concentrated ammonia water, and obtains the product after water recrystallization and purification 6-Methyl-3-aminopyridazine and by-product 6-methyl-pyridazin-3-one.

[0022] The mass concentration of the concentrated ammonia water is 25%-28%, the temperature of the ammoniation reaction is 120°C-150°C, and the reaction pressure is 0.2-0.4MPa.

[0023] After the ammoniation reaction is completed, after the reaction solution is cooled to room temperature, the pH of the reaction solution is adjusted to 7-8 with dilute hydrochloric acid, and then after standing for 48 hours, a light yellow solid precipitates from the reaction solution, which is filtered to obtain 6-methyl- 3-aminopyridazine.

[0024] Concentrate the filtrate from which 6-methyl-3-aminopyridazine has been filtered out, a...

Embodiment 1

[0028] At room temperature, add 3-chloro-6-methylpyridazine (50g, 0.39mol) and concentrated ammonia water (250ml) into the autoclave, raise the temperature to 120-130 degrees, and the pressure to 0.2-0.3MPa, 120-130 Insulated and stirred for 5-12 hours under the temperature. After cooling down and depressurizing and deflation, test. Adjust the pH to 7 with dilute hydrochloric acid, and let it stand for 48 hours. A large amount of light yellow solid precipitated, and the product 6-methyl-3-aminopyridazine (25.5 g, 0.23 mol) was obtained by filtration, with a purity of 98% and a yield of 60%.

[0029] The above-mentioned filtrate was concentrated to remove two-thirds of the volume of water, the pH was adjusted to 5, and it was left to stand for 24 hours. Off-white solids were precipitated, and the by-product 6-methyl-pyridazin-3-one (15.3g, 0.14mol) was obtained by filtration. 96%.

Embodiment 2

[0031] At room temperature, add 3-chloro-6-methylpyridazine (500g, 3.9mol) and concentrated ammonia water (2.5L) into the autoclave, raise the temperature to 120-130 degrees, and the pressure to 0.2-0.3MPa, 120- Heat preservation and stirring at 130 degrees for 5-12 hours. After cooling down and depressurizing and deflation, test. Adjust the pH to 7 with dilute hydrochloric acid and let it stand for 48 hours. A large amount of light yellow solid precipitated out. The product 6-methyl-3-aminopyridazine (267.7 g, 2.4 mol) was obtained by filtration, with a purity of 98% and a yield of 63%.

[0032] The above-mentioned filtrate was concentrated to remove two-thirds of the volume of water, the pH was adjusted to 5, and it was left to stand for 24 hours. Off-white solids were precipitated, and the by-product 6-methyl-pyridazin-3-one (140.5g, 1.3mol) was obtained by filtration. The purity 96%.

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Abstract

The invention provides a method for industrial preparation of 6-methyl-3-aminopyridazine. The method comprises the following steps: 6-methyl-3-chloropyridazine is taken as the raw material, and subject to ammoniation with strong aqua ammonia, and the product is purified by recrystallization using water to obtain 6-methyl-3-aminopyridazine and a byproduct 6-methyl-pyridazine-3-ketone; and the byproduct 6-methyl-pyridazine-3-ketone is subject to chlorination with phosphorus oxychloride to generate 6-methyl-3-chloropyridazine. The method is simple in process, few in steps and high in yield, and as the byproduct can be regenerated into the reaction raw material, the production cost is reduced.

Description

【Technical field】 [0001] The invention relates to an industrialized preparation method of 6-methyl-3-aminopyridazine. 【Background technique】 [0002] Pyridazine is an important class of aromatic heterocyclic compounds with strong antiviral, pressure drop, cardiotonic, anticancer and other physiological activities. The pyridazine ring structure widely exists in natural products, pharmaceutical intermediates and pesticide compounds. [0003] 6-Methyl-3-aminopyridazine is a very important pharmaceutical and chemical intermediate, but so far there is no effective method for the industrial scale-up production of this product. The existing production and preparation method basically uses 6-methyl-pyridazin-3-one as a raw material, first chlorinated by phosphorus oxychloride, and then 6-methyl-3-amino Pyridazine. But so far, there are no good and efficient industrialized production reports. [0004] A document (Received, June 18th, 1946; Publ: EP1555269A1 (2005\07\20)) discloses...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D237/20
Inventor 高平章吴洪谢晓兰吕凤娇姬长鹏
Owner QUANZHOU NORMAL UNIV
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