Synthetic method of 2,2-dichloro-1,3-benzodioxole-4-formaldehyde

A technology of benzodioxol and synthesis method, which is applied in the field of synthesis of 2,2-difluoro-1,3-benzodioxol-4-carbaldehyde, can solve the problem that is not suitable for large-scale industrial production and the process is smooth It is beneficial to large-scale industrial production, high yield, and simple post-treatment.

Active Publication Date: 2017-05-24
SHANGHAI SHENGNONG PESTICIDE
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Problems solved by technology

[0004] Most of the synthetic methods of 2,2-difluoro-1,3-benzodioxol-4-carbaldehyde reported at present have the following technical problems: the synthetic route is long, the synthetic steps are many, the reaction conditions are harsh, and the yield is low , expensive raw materials, etc.
For example, in patent CN101851225, o-cresol is used as a starting material, and 3-methylsalicylaldehyde is obtained through ortho-directed formylation, and 3-methylsalicylaldehyde is converted into 3-methylcatechol through Dakin reaction, and then Without separation and purification, it directly reacts with dichloromethane or dibromomethane to generate 4-methylbenzodioxol, and then generates the target product through three steps of chlorination, fluorination and oxidation, with a yield of 43%; however, the synthesis process In China, triethylamine hy...

Method used

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  • Synthetic method of 2,2-dichloro-1,3-benzodioxole-4-formaldehyde

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[0032] In a preferred embodiment, the above-mentioned synthetic method comprises the following steps:

[0033] S1: Add 3-methoxy-2-hydroxybenzaldehyde and alkali to a protic solvent, then add hydrogen peroxide dropwise to carry out a hydrolysis reaction; after the reaction is complete, after-treatment, 2,3-dihydroxybenzaldehyde is obtained;

[0034] S2: Add the aqueous solution of 2,3-dihydroxybenzaldehyde and alkali to an aprotic solvent, then add difluorodichloromethane to react; after the reaction is complete, post-treatment, the 2,2-difluoro-1 ,3-Benzodioxol-4-carbaldehyde.

[0035] In a further preferred embodiment, the bases described in S1 and S2 are inorganic bases, and are each independently selected from any of the following: hydroxides of alkali metals, carbonates of alkali metals, acids of alkali metals formula carbonate.

[0036] In a further preferred embodiment, the bases described in S1 and S2 are inorganic bases, and are each independently selected from any ...

Embodiment 1

[0050] Example 1 Synthesis of 2,3-dihydroxybenzaldehyde

[0051]

[0052] In a 2L four-necked flask, add 121.0g (0.80mol) (1.0eq) 3-methoxy-2-hydroxybenzaldehyde, then drop 128g (0.80mol) (1.0eq) of 25% NaOH aqueous solution within 0.5h ), and then added dropwise 940ml (3.5eq) of 10% H 2 o 2 , Control the temperature not to exceed 50°C during the dropwise addition, heat to 60°C after the dropwise addition, keep warm and reflux for 18h. After the reaction is completed, add 10% hydrochloric acid to acidify to pH=1~2, let it stand still, extract with dichloromethane, separate the lower organic phase, remove the dichloromethane by precipitation, collect the distillate at 115~120℃ / 15mmHg by distillation, cool Finally, 84.2 g of a light yellow solid, namely 2,3-dihydroxybenzaldehyde, was obtained with a yield of 85% and mp=104-105°C.

Embodiment 2

[0053] Example 2 Synthesis of 2,3-dihydroxybenzaldehyde

[0054] In a 2L four-necked flask, add 121.0g (0.80mol) (1.0eq) 3-methoxy-2-hydroxybenzaldehyde, then drop 128g (0.80mol) (1.0eq) of 25% NaOH aqueous solution within 0.5h ), and then added dropwise 10% of 671ml (2.5eq) of H 2 o 2 , Control the temperature not to exceed 50°C during the dropwise addition, heat to 60°C after the dropwise addition, keep warm and reflux for 18h. After the reaction is completed, add 10% hydrochloric acid to acidify to pH=1~2, let it stand still, extract with dichloromethane, separate the lower organic phase, remove the dichloromethane by precipitation, collect the distillate at 115~120℃ / 15mmHg by distillation, cool Finally, 66.3 g of a light yellow solid, namely 2,3-dihydroxybenzaldehyde, was obtained, with a yield of 67%, and mp=104-105°C.

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Abstract

The invention provides a synthetic method of 2,2-dichloro-1,3-benzodioxole-4-formaldehyde. The synthetic method comprises the following steps of: adding 3-methoxyl-2-hydroxybenzaldehyde and alkali into a protonic solvent, then dropwise adding hydrogen peroxide, and performing hydrolysis reaction; after the complete reaction, performing the after-treatment to obtain 2,3-dihydroxy benzaldehyde; adding an aqueous solution of the 2,3-dihydroxy benzaldehyde and alkali into the protonic solvent, and then adding dichlorodifluoromethane to perform the reaction; and after the complete reaction, performing the after-treatment to obtain the 2,2-dichloro-1,3-benzodioxole-4-formaldehyde. According to the synthetic method, the target product can be obtained from an initial raw material 3-methoxyl-2-hydroxybenzaldehyde by virtue of two-step chemical reaction. The reaction method is moderate in reaction conditions, simple in steps, low in cost, environment-friendly, high in yield, capable of facilitating the industrialized mass production, and capable of setting a foundation for the subsequent successful synthesis of fludioxonil, so that the synthetic method has good application prospect and market potential.

Description

technical field [0001] The invention relates to a method for synthesizing a chemical pesticide intermediate, in particular to a method for synthesizing 2,2-difluoro-1,3-benzodioxol-4-carbaldehyde. Background technique [0002] Fludioxonil is a highly efficient and safe new type of systemic fungicide pesticide. It is currently one of the world's largest sales of seed treatment agents and has broad market prospects. 2,2-difluoro-1,3-benzodioxol-4-carbaldehyde is the key intermediate of the insecticide fludioxonil, and its molecular formula is: C 8 h 4 f 2 o 3 , CAS number: 119895-68-0, English name: 2,2-Difluorobenzodioxole-4-carboxaldehyde. The chemical structural formula is as follows: [0003] [0004] Most of the synthetic methods of 2,2-difluoro-1,3-benzodioxol-4-carbaldehyde reported at present have the following technical problems: the synthetic route is long, the synthetic steps are many, the reaction conditions are harsh, and the yield is low , expensive raw ...

Claims

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Application Information

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IPC IPC(8): C07D317/54
Inventor 叶振君孔前广毕强顾浩桦韩海平方燕张芝平徐海燕
Owner SHANGHAI SHENGNONG PESTICIDE
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