Pyrrole and its derivatives have gained much interest in both biological and material science.They have played a vital role in pharmaceutical chemistry owing to their diversified biological activities such as antibacterial, antiviral, anti-inflammatory, and antitumor properties. The Paal-Knorr reaction, whereby 1,4-dicarbonyl compounds are converted to pyrroles via condensation with primary amines or ammonia in the presence of acidic catalysts, has been known as the most reliable method for the synthesis of pyrroles. Numerous catalysts were developed to facilitate the Paal-Knorr synthesis of 2,5-disubstituted pyrroles, such as Bronsted acids, Lewis acids, deep eutectic solvents, metal triflates,15 and metal-organic frameworks.16 Friedel-Crafts acylation was known as a classical organic transformation for the synthesis of aromatic ketones.17"19 Traditionally, those reactions required the use of an over-stoichiometric amount of strong Lewis acids such as A1C13, BF3, FeCl3, TiCl4, or SnCl2. These methods suffer from the high loading, toxicity and corrosive properties of the catalysts, the lack of catalyst regeneration, the mass production of hazardous wastes, and the laborious purification of products.
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