Sonochemically assisted synthesis of N-substituted pyrroles catalyzed by ZnO nanoparticles under solvent-free conditions

Solvent‐Free Synthesis of Pyrroles: An Overview

“…A solvent‐free synthesis of 1,2,3,5‐tetra substituted pyrrole derivatives under sonochemical assistance using ZnO nanoparticles as a catalyst was disclosed (Scheme 21). [76] This three component one‐pot synthesis using amines, β‐dicarbonyls and α‐bromo ketones using highly efficient nano ZnO particles afforded moderately good yields. Extensive examinations were done to check the influence of various reaction parameters like solvent, catalyst loading, and time and optimized the amount of catalyst as 15 mol%.…”

Ultrasound and Nano‐Catalysts: An Ideal and Sustainable Combination to Carry out Diverse Organic Transformations

“…Shahvelayati et al . (Table ) synthesized a series of 1,2,3,5‐tetrasubstituted pyrrole ( 45 ) via a one‐pot three‐component reaction of various primary amines ( 7 ), 1,3‐dicarbonyl compounds ( 4 , 4 a ) and α‐bromoketones ( 44 ) in the presence of a catalytic amount of ZnO nanoparticles under ultrasonic irradiation and solvent‐free conditions at 40 °C. In absence of ultrasound the reaction (Table , entry 1) required six hours using the same amount of catalyst even at 80 °C.…”

The Hantzsch Pyrrole Synthesis: Non-conventional Variations and Applications of a Neglected Classical Reaction

“…Shahvelayati and co-workers described an efficient Hantzsch pyrrole synthesis performed in the absence of solvents, under irradiation with an ultrasonic cleaner with a frequency of 60 kHz and an intensity of 285 W, and catalyzed by ZnO nanoparticles (Scheme 15). 26 The catalyst was prepared by treatment of zinc acetate with sodium hydroxide in an ionic liquid, followed by irradiation with ultra-sound for 1.5 hours (Scheme 16). It was observed that particles with a smaller crystallite size were obtained in the ionic liquid than in water.…”