Modified chitosan-zeolite supported Pd nanoparticles: A reusable catalyst for the synthesis of 5-substituted-1H-tetrazoles from aryl halides

A novel heterogeneous catalyst has been developed using chitosan-zeolite supported Pd nanoparticles (PdNPs@CS-Zeo) and used in an efficient synthesis of 5-substituted-1H-tetrazoles from aryl halides with high yields for relatively short reaction times with an easy work-up procedure. In this method, highly effective and reusable PdNPs@CS-Zeo catalyst was used in the reaction of various aryl iodides/bromides with K4[Fe(CN)6] as a non-toxic cyanide source to catalyze the [2 + 3] cycloaddition of the corresponding aryl nitriles with NaN3 in the sequential one-pot preparation of 5-substituted-1H-tetrazoles. The synthesized PdNPs@CS-Zeo nanocatalyst was characterized using XRD, FTIR, TEM, HRTEM, XPS, Raman, TG-DTG, ICP-OES, BET, and EDS mapping. Additionally, the nanocatalyst could be effectively separated by filtration and reused for multiple times without significant decrease of catalytic activity.

Automated summary

A novel heterogeneous catalyst PdNPs@CS-Zeo has been developed for the efficient synthesis of 5-substituted-1H-tetrazoles, with high reaction yields and easy work-up procedure. The synthesized PdNPs@CS-Zeo nanocatalyst showed excellent catalytic activity and could be reused multiple times.