Method for preparing (E)-2-(2-substituted phenyl)-2-methoxyimino acetic acid derivative

Abstract

The invention relates to a method for preparing a (E)-2-(2-substituted phenyl)-2-methoxyimino acetic acid derivative. The method comprises the following steps: (1) carrying out pinner reaction on a proper raw material acyl cyanide shown in a formula (II) which is shown in the specification and alcohol in an organic solvent in the presence of acid and alkali metal halide to prepare a glyoxylic acid derivative shown in a formula (III); (2) carrying out reaction with hydroxylamine in an organic solvent to generate oxime shown in a formula (IV) and then methylating or oximating by O-methylhydroxyl amine to prepare a mixed isomer of a 2-(2-substituted phenyl)-2-methoxyimino acetic acid derivative; and (3) in the presence of acid, isomerizing in the organic solvent and at a certain temperature range and treating, crystallizing and separating to obtain a target product. According to the method provided by the invention, hydrogen chloride gas is not used, and the method is less in equipment corrosion, hardly causes the environmental pollution, is small in wastewater quantity, convenient to operate and high in synthetic yield and is an environment-friendly chemical synthetic process.

Description

technical field [0001] The invention relates to a chemical process, in particular to a method for preparing (E)-2-(2-substituted phenyl)-2-methoxyiminoacetic acid derivatives. The prepared compound is shown in formula (I): [0002] [0003] In the formula [0004] A is C 1 -C 4 Alkoxy or methylamino, [0005] X is the following group: CH 3 or halomethyl or O-aryl or H 2 C-O-aryl or H 2 C-O-N=CR'-aryl, [0006] Among them, R is H or C 1 -C 4 alkyl, [0007] Aryl or H in the O-aryl or H2C-O-aryl 2 C-O-N=CR'-aryl, which is phenyl or naphthyl, they can be substituted by 1 to 3 of the following groups: C 1 -C 4 Alkyl, C 1 -C 4 Alkoxy, C 1 -C 4 Haloalkyl, C 1 -C 4 Haloalkoxy, halogen, cyano, nitro, formyl, acetyl, aryl, aryloxy, benzyl, benzyloxy, heteroaryl, heteroaryloxy, C 1 -C 4 Cycloalkyl, C 1 -C 4 Dialkylamino, CO 2 CH 3 , CO 2 C 2 h 5 , [0008] Heteroaryl is a substituted or unsubstituted aromatic five- or six-membered heterocyclic ring....

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Problems solved by technology

[0013] U.S. Patent No. 5,221,762A (1993) discloses that 2-(2-methylphenoxymethyl)benzoyl cyanide is passed through excessive hydrogen chloride gas at low temperature in the presence of acetic anhydride in an organic solvent, so that it can undergo alcoholysis with alcohol The method of reaction synthesis 2-(2-methylphenoxymethyl) benzaldehyde methyl formate, the shortcoming of this method is (1) needs to carry out at the temperature lower than 0 ℃ when passing into hydrogen chloride, to equipment requirement High, harsh operating conditions, (2) hydrogen chloride gas is very easy to leak, highly corrosive to equipment, and easy to cause pollution to the environment, (3) due to the use of a large amount of hydrogen chloride gas, it needs to be absorbed and treated with more water, so it contains hydrogen chloride The amount of acid wastewater is large; also in the subsequent conversion of isomers, excessive hydrogen chloride gas is also used. This method is unfavorable to operation, equipment and environment

[0014] Chinese patent CN1203583A (1998) discloses a preparation method of o-chloromethylphenylmethane glyoxylic acid derivatives. The method is to dissolve o-chloromethylbenzoyl cyanide in acetic acid and feed hydrogen chloride gas to carry out hydrolysis reaction Formation of amide, after separation with C 3 -C 8 Alkanol reaction, and then react with O-methylhydroxylamine to generate the corresponding glyoxylic acid derivatives. The disadvantage of this method is that hydrogen chloride gas is also used, and the separation of amide is acetic acid, which is easy to cause personal injury

[0016] Although it is mentioned in the above-mentioned documents that benzoyl cyanide of formula (II) can undergo alcoholysis reaction with alcohol in the presence of inorganic and organic acids such as sulfuric acid, phosphoric acid, p-toluenesulfonic acid, etc., no further explanations and requirements have been made.

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