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Industrial synthesis method of tebuconazole intermediate alpha

An intermediate, tebuconazole technology, applied in the field of industrial synthesis of tebuconazole intermediate α, can solve the problems of large amount of disproportionated impurities, increased content of target products, waste of raw materials, etc., and achieve mild reaction conditions and low production costs Effect

Inactive Publication Date: 2019-04-12
SHANGHAI SHENGNONG PESTICIDE
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] However, in the prior art, in the one-step reaction of synthesizing the above key intermediate α, the process synthesis conditions have not been successfully optimized, resulting in a large amount of two disproportionated impurities, p-chlorobenzyl alcohol and p-chlorobenzoic acid
In the actual production process of the factory, the content of p-chlorobenzoic acid can reach 10%, while the content of p-chlorobenzyl alcohol can reach 5%. improvement

Method used

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  • Industrial synthesis method of tebuconazole intermediate alpha
  • Industrial synthesis method of tebuconazole intermediate alpha
  • Industrial synthesis method of tebuconazole intermediate alpha

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preparation example Construction

[0030] In a preferred embodiment, the industrial synthesis method of the tebuconazole intermediate α comprises the following steps:

[0031] After adding organic solvent, alkali, pinacolone and antioxidant to the reaction vessel, add p-chlorobenzaldehyde in 6-8 batches, and react completely at 30-50°C; cool the reaction solution below 10°C, stir, Suction filtration, take the filter cake and wash it with methanol, and apply the obtained mother liquor to the organic solvent of the next batch of reactions; dry the washed filter cake to obtain the target product tebuconazole intermediate α.

[0032] In a further preferred embodiment, the antioxidant is selected from any one of the following: butylhydroxyanisole, dibutylhydroxytoluene, tert-butylhydroquinone, and sodium dithionite.

[0033] In a further preferred embodiment, the molar weight of the antioxidant is 0.1-5.0% of the molar weight of p-chlorobenzaldehyde.

[0034] In a further preferred embodiment, the molar ratio of th...

Embodiment 1

[0040] Add 120 mL of methanol and 2.5 g of sodium hydroxide (0.0625 mol, 0.2 eq) into a 250 mL three-necked flask, and stir mechanically to cool down to room temperature. Next, add 31.2g (0.313mol, 1.1eq) of pinacolone, then add 0.26g (1.43mmol, 0.5%eq) of butylated hydroxyanisole, raise the temperature to 43°C, and add 5.0g of p-chlorobenzaldehyde every 0.5h , A total of 8 batches were added, with a total of 40.0g (0.286mol, 1.0eq); the addition was completed and the reaction was held for 12 hours, and solids were precipitated during the reaction. After the reaction is complete, cool the reaction liquid to below 10°C, stir for 2 hours, filter with suction, take the filter cake and rinse it with 10mL of methanol, dry the washed filter cake to obtain the tebuconazole intermediate α; the mother liquor is reserved for the next batch The reaction is applied mechanically, specifically, the mother liquor is applied mechanically 3 times, and the pinacolone add-on is 31.2g (0.313mol, ...

Embodiment 2

[0043]Add 120 mL of methanol and 3.0 g of sodium hydroxide (0.075 mol, 0.26 eq) into a 250 mL three-necked flask, and stir mechanically to cool down to room temperature. Next, add 31.2g (0.313mol, 1.1eq) of pinacolone, then add 0.10g (0.57mmol, 0.2%eq) of butylated hydroxyanisole, raise the temperature to 45°C, and add 6.67g of p-chlorobenzaldehyde every 0.5h , a total of 6 batches were added, with a total of 40.0g (0.286mol, 1.0eq); the addition was completed and the reaction was kept for 15 hours, and solids were precipitated during the reaction. After the reaction is complete, cool the reaction liquid to below 10°C, stir for 2 hours, filter with suction, take the filter cake and rinse it with 10mL of methanol, dry the washed filter cake to obtain the tebuconazole intermediate α; the mother liquor is reserved for the next batch The reaction is applied mechanically, specifically, the mother liquor is applied mechanically 1 time, and the pinacolone addition is 30g (0.3mol, 1.0...

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Abstract

The invention provides an industrial synthesis method of tebuconazole intermediate alpha. The method includes the following steps that an organic solvent, alkali, pinacone and an antioxidant are addedinto a reaction vessel, p-chlorobenzaldehyde is added in batches, the reaction is completed at 30-50 DEG C, and then aftertreatment is conducted to obtain the tebuconazole intermediate alpha. The industrial synthesis method successfully optimizes the reaction conditions such as the starting material equivalence ratio, the feeding sequence and mode, the reaction temperature, alkali selection and dosage, and solvent selection, and appropriate antioxidants are added to significantly reduce disproportionation reaction. In addition, mother liquor obtained by aftertreatment is easy to apply, and the production cost is thus reduced. The industrial synthesis method of tebuconazole intermediate alpha has mild reaction conditions, the average yield of a target product is over 96% and the purity ofthe target product is over 98%. Therefore, the large-scale industrial production can be achieved.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis, and in particular relates to an industrial synthesis method of tebuconazole intermediate α. Background technique [0002] Tebuconazole is a triazole fungicide developed by Bayer in 1986. The structural formula of tebuconazole is as follows: [0003] [0004] Tebuconazole is widely used in Europe and America. In recent years, the global annual sales have exceeded 200 million US dollars, which has produced relatively large social and economic benefits. Tebuconazole is mainly used for seed treatment and foliar spraying on crops such as wheat, vegetables, bananas, and apples. Diseases, such as wheat powdery mildew, wheat loose smut, wheat sheath blight, wheat snow rot, wheat take-all, wheat bunt, barley moire, barley loose smut, barley sheath blight, etc. . [0005] In the existing tebuconazole synthesis process, a kind of enone compound shown in the following formula is a key interm...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C45/74C07C49/235
CPCC07C45/74C07C49/235
Inventor 叶振君毕强徐海燕王涛韩海平
Owner SHANGHAI SHENGNONG PESTICIDE
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