Method for synthesizing albendazole

Abstract

The invention relates to a method for synthesizing albendazole. The method comprises the following steps of: (a) adding carbendazim, sodium sulfocyanate and glacial acetic acid to a reactor, dropwise adding 28% hydrogen peroxide while controlling the temperature to be 25-40 DEG C, carrying out heat preservation and reaction for 4-6 hours after the dropwise adding process is completed, and obtaining thiocyanide after glacial acetic acid is recovered through negative-pressure distillation; and (b) adding 20% aqueous potassium hydroxide solution to the thiocyanide while adding benzyltriethylammonium chloride, then dropwise adding 1-bromopropane, and reacting for 4-8 hours while controlling the temperature to be 45-60 DEG C, thereby obtaining the albendazole. According to the method, the potential safety hazard caused by the fact that a highly toxic substance, namely chlorine gas, is used for preparing albendazole is avoided successfully, and the influence on the quality and yield of the product, caused by side reactions resulting from the adoption of the chlorine gas, is eliminated successfully, so that the quality and yield of an intermediate are improved greatly; meanwhile, the adoption of alkali sulfide is cancelled, and then, the environmental pollution caused by a byproduct, namely thioether, produced due to excessive alkali sulfide is avoided, so that the method is perfectly suitable for industrial production; and furthermore, all the raw materials are low in cost and are purchased easily, and the operation is safe.

Description

technical field [0001] The present invention relates to the synthetic method of organic compound, specifically, a kind of synthetic method of albendazole. Background technique [0002] Albendazole (Albendazole), molecular formula: C 12 h 15 N 3 o 2 S, molecular weight: 265.33, is a broad-spectrum, high-efficiency, and low-toxic insect repellent listed by Smith Kline Company in the United States. It is still widely used at home and abroad. It has a variety of synthesis methods, mainly o-nitroaniline method, o-phenylenediamine method, and carbendazim method. Among them, there are two carbendazim methods. Method 1: carbendazim is chlorosulfonated and iron powder reduced Repropylation, the disadvantage of this preparation process is the use of highly poisonous chlorosulfonic acid, and a large amount of waste acid and iron sludge are produced during the synthesis process, the production risk is high, and there is no effective treatment method for the three wastes with the sam...

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Problems solved by technology

[0004] The disadvantage of this method is that it uses highly poisonous chlorine gas, which brings serious safety hazards to production. At the same time, a large amount of by-product chlorides are produced in the synthesis process, which seriously affects its yield and quality. On the other hand, this method uses vulcanization Alkali is used as a reducing agent, and excess alkali sulfide reacts with bromopropane in the next step of propylation to produce thioether with a serious stench, which is difficult to handle and severely restricts industrial production. Therefore, this method cannot be used in industrial production at present.

In summary, there is an urgent need for a method to avoid the use of highly toxic drugs, while the quality of the intermediate and the yield are greatly improved, and the by-products that do not pollute the environment are produced, and are fully suitable for industrial production. This method has not been reported yet