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

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 ...

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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 hydrogen trifluoride, which has a long supply and high price, needs to be used, so it is difficult to use it in large-scale industrial production

[0005] As another example, Liu Shaochun et al. (Pesticides, 2011, 5(50), 329-331) reported a synthetic method, including: using o-cresol as a starting material to prepare 3-methylcatechol, and then Chlorination, chlorination, fluorine exchange reaction, hydrolysis to get 2,2-difluorobenzo[1,3]dioxole-4-carbaldehyde, the overall yield is 35.1%, therefore, obviously there is a yield that is too low technical problem

In addition, Li Chao et al. (Modern Pesticides, 2009, 8(3), 19-21) reported that 2,2- The method of difluoro-1,3-benzodioxol-4-carbaldehyde, however, has a long synthetic route, too many synthetic steps, and low process fluency, so it is also not suitable for large-scale industrial production

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