2-branch acylation method of solid acid continuous loaded catalyzed aromatic heterocyclic compound

Abstract

The invention relates to the technical field of chemical compounds, in particular to a 2-site acylation method of solid acid continuous loaded catalyzed aromatic heterocyclic compound. The method comprises the following steps: filling a continuous reaction device with solid acid catalyst, and continuously adding aromatic heterocyclic compounds and acylating agents to trigger the Friedel-Crafts acylation. The method is a highly efficient green synthesis process which applies heterogeneous catalysis to make the products easily separable, thereby avoiding the use of Lewis acid such as AlCl3 and eliminating the environmental destruction; the method uses continuous operation with mild reaction conditions and short reaction time. The catalyst does not have to be separated and can be recycled. The reaction recovery rate can reach 95% or above. The reaction selectivity is superior. The purity of the product can reach 92% or above. The method is simple in operation, and has obvious advantages especially in enlarged production.

Description

technical field [0001] The invention relates to the technical field of chemical synthesis, in particular to a method for continuously supporting solid acid to catalyze the 2-position acylation of aromatic heterocyclic compounds. Background technique [0002] Discovered in 1887, the Friedel–Crafts acylation reaction is one of the oldest methods for forming C-C bonds. So far, it is still an important means for introducing carbonyl groups on aromatic rings used in academia and industry. [0003] Many natural products and biologically active compounds contain substituted aromatic heterocyclic structures such as pyrrole, furan, thiophene, and indole. Generally, the Friedel-Crafts acylation reaction of pyrrole and indole and other heterocyclic aromatic compounds requires a stoichiometric Lewis acid , such as: AlCl 3 、TiCl 4 , BF 3 , BeCl 2 , SnCl 4 or SbCl 5 etc. In addition, strong protic acids such as H 2 SO 4 , HF or super acid such as HF·SbF 5 and HSO 3 F·SbF 5 Als...

AI Technical Summary

Problems solved by technology

However, regardless of Lewis acid, transition metal salt or organic small molecule catalyst, their types are homogeneous catalysts. Although they have high activity and selectivity in many chemical synthesis fields, most of the reported catalysts of this type It also has its own huge shortcomings: when using Lewis acid, it needs a stoichiometric amount; the post-treatment is cumbersome, especially when using AlCl 3 When the liquid separation is difficult; the reaction time is long; the reaction temperature is generally high; the reaction conditions are harsh, and most of them are sensitive to water vapor; a large amount of corrosive gas and a large amount of inorganic salts will be formed during the reaction, causing damage to the environment; Moreover, the cost of transition metal salts is relatively high; these catalysts cannot be recycled and reused, and the economy is insufficient; etc.

The reaction requires acid modification of the molecular sieve, and the batch reaction is carried out in a single-necked bottle. The operation is cumbersome, the selectivity of the reaction is low, and the separation and purification of the product is difficult, which is not conducive to industrial scale-up application.

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