Clay‐catalyzed synthesis of 5‐substituent 1‐H‐tetrazoles

Abstract

In this study, the possibility of 5-substituted 1-H-tetrazoles synthesis using clays as catalyst was investigated. The reaction of a series of aromatic nitriles with sodium azide was catalyzed by montmorillonite K-10 or kaolin clays in water or DMF as solvent. Conventional heating or ultrasonic irradiation was used to promote reaction. The amount of nitrile to sodium azide mole ratio, amount of catalyst, reaction time, and solvent type were optimized. The versatility of this method was checked by using various nitriles, which showed reasonable yields of tetrazole formation. It was found that using nitriles with electron-withdrawing groups result in both higher yields and lower reaction times. The catalysts could be reused several times without significant loss of their catalytic activity. Compared to conventional heating, ultrasonic irradiation reduced reaction times and increased catalyst activity. The present procedure is green and offers advantages, such as shorter reaction time, simple workup, and recovery and reusability of catalyst.

Porous Catalytic Systems in the Synthesis of Bioactive Heterocycles and Related Compounds

“…Montmorillonite K-10 or kaolin clays were used as catalysts in the synthesis of 5-substituted 1H-tetrazoles 35 (Scheme 25) [111]. The reaction was carried out using a series of aromatic nitriles with sodium azide, in water or DMF as solvent, at 373-403 K. The reaction was activated under conventional heating or ultrasonic irradiation.…”

Recent Advances in the Ultrasound-Assisted Synthesis of Azoles

“…In 2010, Chermahini and co-workers reported the clay-catalyzed preparation of tetrazoles (127) under ultrasound (Scheme 35) (Chermahini et al, 2010). Compared to conventional heating, ultrasonic irradiation reduced the reaction times and increased the catalyst activity.…”

Synthesis and characterization of Fe2O3–ZnO–ZnFe2O4/carbon nanocomposite and its application to removal of bromophenol blue dye using ultrasonic assisted method: Optimization by response surface methodology and genetic algorithm

“…The US irradiation causes formation and collapse of micrometrical bubble formation by dispersion of a pressure wave through a liquid. The US irradiation and micrometrical bubbles improve the mass transfer through convection pathway emerged from physical phenomena, including micro-streaming, micro-turbulence, acoustic (or shock) waves and micro-jets without significant change in equilibrium characteristics of the adsorption/desorption system [18][19][20].…”