A kind of preparation method of thiabendazole intermediate

Abstract

The invention provides a preparation method of a thiabendazole intermediate. The preparation of the thiabendazole intermediate shown in formula (1) from a raw material containing o-phenylenediamine comprises the following steps: The amine raw material is subjected to condensation reaction to obtain crude product 1; the crude product 1 is subjected to halogenation reaction to obtain crude product 2; the crude product 2 is subjected to decarboxylation reaction and purified to obtain the thiabendazole intermediate. The method provided by the invention has low cost of raw materials, simple synthesis route, no catalyst, solvent recovery and mechanical application, almost zero discharge of three wastes, avoiding the impact on the environment, mild reaction conditions, simple operation, and a yield as high as 80%, which is suitable for modern Industrial production. R is Cl or Br.

Description

technical field [0001] The invention relates to the field of organic synthesis, in particular to a preparation method of a thiabendazole intermediate. Background technique [0002] 2-(2-Chloroacetyl)benzimidazole, white solid, is an important intermediate of thiabendazole. At present, domestic and foreign patents, CN102816120A, CN101712677A, CN106349235A, CN103204849A and other reports, the route of synthesizing thiabendazole intermediates is mainly based on the condensation reaction of o-phenylenediamine and lactic acid under acidic conditions, and then using a large amount of high Potassium manganese is oxidized or directly carries out condensation reaction with o-phenylenediamine and pyruvic acid under acidic conditions, and then carries out halogenation reaction with halogenating reagent, the process yield is low, pyruvic acid is expensive, the process is unsafe, and the operation is difficult, The large amount of three wastes has a great impact on the environment. Unde...

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Problems solved by technology

At present, domestic and foreign patents, reports such as CN102816120A, CN101712677A, CN106349235A, CN103204849A, etc., the route of synthesizing thiabendazole intermediate is mainly based on the condensation reaction of o-phenylenediamine and lactic acid under acidic conditions, and then under acidic conditions with a large amount of high Potassium manganate oxidation or direct condensation reaction with o-phenylenediamine and pyruvic acid under acidic conditions, and then halogenation reaction with halogenating reagents, the process yield is low, pyruvic acid is expensive, the process is unsafe, and the operation is difficult. The amount of three wastes is large, which has a great impact on the environment. Under the current environmental protection pressure, industrialization is difficult.

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