A preparing method of a mebendazole intermediate (3,4-diaminophenyl)phenyl methanone

Abstract

A preparing method of a mebendazole intermediate (3,4-diaminophenyl)phenyl methanone is disclosed. The method includes adding 4-amino-3-nitro diphenylmethanone and a catalyst into an organic solvent, adding a hydrogen donor, and performing transfer hydrogenation reduction to obtain the (3,4-diaminophenyl)phenyl methanone, wherein the catalyst is a Pd-X / C catalyst, and the X is one of Ni, Ru, La, Ce, Co, Li, K, Mg, Ti, Cu or Mo. The method has advantages of mild conditions, simple operation, a high reduction rate, a low cost, high environment protection performance, easy industrial production, and the like.

Description

Technical field [0001] The invention relates to a preparation method of mebendazole intermediate 3,4-diaminobenzophenone, which belongs to the technical field of medicine and chemical industry. Background technique [0002] 3,4-Diaminobenzophenone is a key intermediate in the production of mebendazole, a commonly used insect repellent. Its structural formula is as follows: [0003] [0004] The main method for preparing the compound is to reduce 4-amino-3-nitrobenzophenone. The structural formula of 4-amino-3-nitrobenzophenone is: [0005] [0006] The existing reduction methods reported in the literature mainly include iron powder reduction, stannous chloride reduction, alkali sulfide reduction, Pd / C catalytic hydrogenation and Raney Ni catalytic hydrogenation. [0007] At present, the sodium sulfide reduction method is mainly used in the industry. The product produced by this method is of poor quality, and a large amount of sulfide-containing wastewater is generated during the prod...

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Problems solved by technology

[0007] At present, the sodium sulfide reduction method is mainly used in industry. The products produced by this method are of poor quality, and a large amount of sulfide-containing wastewater will be generated during the production process. The wastewater is difficult to treat and causes serious environmental pollution.

In 1998, Dobrodei et al. (Russian Journal of General Chemistry, 1998, vol.68(4): 620-629) reported the preparation of 3,4-diaminobenzophenone by nickel-catalyzed hydrogenation in tetrahydrofuran at 30-40°C , due to the use of active nickel catalysis, the amount of reaction by-products is large and the product yield is low. At the same time, active nickel is very easy to catch fire in the air, resulting in a huge safety hazard in production.

In 2015, Zhang, Jin et al. (Bioorganic and Medicinal Chemistry, 2015, vol.23(5): 976-984) reported that the catalytic hydrogenation method had a relatively high operating pressure, and the carbonyl group was easily reduced to methylene to form a by-product 4- Benzylphenyl-1,2-diamine not only reduces the reaction yield, but also reduces the purity of the product

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