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The influence of ultrasonic irradiation on catalytic performance of ZnO nanoparticles toward the synthesis of chiral 1‐substituted‐1 H ‐tetrazolederivatives from α ‐amino acid ethyl esters
Author(s) -
Mohamed Yasser Mahmoud A.,
Attia Yasser A.
Publication year - 2020
Publication title -
applied organometallic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 71
eISSN - 1099-0739
pISSN - 0268-2605
DOI - 10.1002/aoc.5758
Subject(s) - chemistry , yield (engineering) , tetrazole , sonication , catalysis , solvent , zinc , nanoparticle , nuclear chemistry , green chemistry , organic chemistry , reaction mechanism , chemical engineering , chromatography , materials science , engineering , metallurgy
In this work, a simple and greener protocol for the synthesis of 1‐substituted 1 H ‐tetrazole derived from α ‐amino acid ethyl esters was demonstrated in the presence of zinc oxide nanoparticles (ZnO NPs) under conventional conditions, with heating (at 60 and 80°C and under reflux) compared with ultrasonic. The effect of solvent was investigated to reveal that the solvent system CH 3 CN/H 2 O was optimum to obtain 1‐substituted 1 H ‐tetrazole in high yield. In addition, the effect of irradiation power was studied, which showed that the yield of the reaction was improved at 200 W and the reaction time was shortened to be 30 min. Also, an improvement in the rate of the reaction and the yield of the products was observed when reactions were carried out under sonication conditions in the presence of ZnO NPs compared with conventional methods using various zinc salts as catalysts. The yields of tetrazole compounds 2a–i under sonication were determined (88–96%). Furthermore, the investigated heterogeneous catalytic system was recycled and reused for five runs with significant production of tetrazole 2a as a model target compound in excellent yields at each reaction cycle. In general, the investigated synthetic strategy for the heterocyclization of α ‐amino acid ethyl ester derivatives to 1‐substituted 1 H ‐tetrazoles was in agreement with the green chemistry point of view.