Method for synthesizing iminostilbene

Abstract

The invention discloses a method for synthesizing iminostilbene, which comprises the following steps: by using 1-phenylindole as a starting raw material, carrying out intramolecular rearrangement reaction on 1-phenylindole under the action of a composite acidic catalytic system to generate iminostilbene; wherein the composite acidic catalytic system is formed by mixing a phosphorus-containing acidic substance and a sulfur-containing acidic substance, the phosphorus-containing acidic substance is one or more of polyphosphoric acid, phosphoric acid and phosphorus pentoxide, and the sulfur-containing acidic substance is one or more of sulfuric acid, methanesulfonic acid and p-toluenesulfonic acid. The phosphorus-containing acidic substance and sulfur-containing acidic substance are used together to form the composite acidic catalytic system, the catalytic system is used in a reaction for catalytic synthesis of iminostilbene, corresponding reaction conditions are optimized, reaction time is shortened, side reactions are reduced, and therefore the method has the advantages of being high in product yield, short in reaction time and the like. The highest yield of the product reaches 83.4%, the purity is 99%, and a good technical effect is achieved.

Description

technical field [0001] The invention relates to a method for synthesizing iminostilbene. Background technique [0002] Iminostilbene is a pharmaceutical intermediate and an important raw material for the synthesis of antiepileptic drugs carbamazepine and oxcarbazepine. In recent years, the demand for carbamazepine and oxcarbazepine has increased. Therefore, it is of great significance to study new and efficient synthetic routes of iminostilbene. [0003] At present, there are many preparation methods of iminostilbene reported in the literature, among which representative ones include: Su Weike et al. (CN101307021A) used iminodibenzyl as raw material to prepare iminostilbene by catalytic hydrogenation at high temperature. The raw material cost of this synthesis method is Higher, poor reaction safety; Yu Feng et al. (CN1616433A) used o-nitrotoluene as a multi-step synthesis method for raw materials, obtained iminostilbene through coupling and cyclization, and the total yield ...

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Problems solved by technology

[0003] At present, there are many preparation methods of iminostilbenes reported in the literature, among which representative ones include: Su Weike et al. (CN101307021A) used iminodibenzyl as raw material to prepare iminostilbene by catalytic hydrogenation at high temperature. The raw material cost of this synthesis method is Higher, poor reaction safety; Yu Feng et al. (CN1616433A) used o-nitrotoluene as a multi-step synthesis method for raw materials, obtained iminostilbene through coupling and cyclization, and the total yield was about 40%. High, the reaction process is complicated, and there are many impurities; Song Guoqiang et al. (CN103113302A) proposed a one-step synthesis of iminostilbene, starting from 1-phenylindole, and catalyzed by polyphosphoric acid (PPA) to obtain the target product iminostilbene. The method is simple to operate , but has the disadvantages of long reaction time and low yield

[0004] In summary, in the synthesis technique of iminostilbene at present, there are deficiencies such as high raw material cost or low yield or complex reaction process, research and development of its new The synthesis process has great application value