Reusable ZnCr2O4 Nano Catalyzed One Pot Three-Component Cycloaddition Reaction for Synthesis of Azetidine Derivatives under Ultrasound Irradiation

A versatile and effectual, three-component one pot (2 pi + 2 pi) cycloaddition reaction to the synthesis of substituted azetidines in the excellent yields is described. The reaction of isonicotinic acid hydrazide (1) as starting materials. Design and preparation of N-(7-R)-2-oxa-8-azabicyclo[4.2.0]octan-8-yl)isonicotinamide derivatives (4a-h) was carried out by condensation of isoniazid (1) with aromatic aldehyde (2a-h), ZnCr2O4 nano catalyzed one-pot cycloaddition of isoniazid Schiff base with pyran (3) under ultrasonic irradiation. Moreover, the Prepared ZnCr2O4 nanoparticles were easily recovered by corresponding solvent and reused for next synthesis of derivatives without significant loss of their catalytic activity. Prepared ZnCr2O4 nanoparticles were confirmed by XRD, EDX, TEM, HRTEM, TGA-DTA and all substituted azetidines were characterized by H-1 NMR, C-13 NMR, FT-IR, mass and elemental analysis.

Automated summary

A versatile and efficient three-component one-pot (2π + 2π) cycloaddition reaction was used for the synthesis of substituted azetidines in good yields. The ZnCr2O4 nanoparticles catalyst could be easily recovered and reused, and the synthesized products were characterized by various analytical methods.