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Molecules 2018, 23(9), 2092;

Design, Synthesis, and Antimicrobial Evaluation of Novel Pyrazoles and Pyrazolyl 1,3,4-Thiadiazine Derivatives

Chemistry Department, Faculty of Science, Jazan University, Jazan 2097, Saudi Arabia
Received: 24 July 2018 / Revised: 18 August 2018 / Accepted: 19 August 2018 / Published: 21 August 2018
(This article belongs to the Special Issue Pyrazole Derivatives)
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A novel series of pyrazolyl 1,3,4-thiadiazines 5ac, 8ac, 12, 15ac, 17ac, and 20 was prepared from the reaction of pyrazole-1-carbothiohydrazide 1a,b with 2-oxo-N′-arylpropanehydrazonoyl chloride, 2-chloro-2-(2-arylhydrazono)acetate, and 3-bromoacetylcoumarin. Moreover, the regioselective reaction of 5-pyrazolone-1-carbothiohydrazide 1a with 4-substituted diazonium salts and 4-(dimethylamino)benzaldehyde gave the corresponding hydrazones 21ac and 22. The newly prepared compounds were characterized by spectroscopy and elemental analysis. Many new synthesized compounds showed considerable antimicrobial activity against tested microorganisms. Hydrazones 21ac and 22 showed remarkable antibacterial and antifungal activities. 4-(2-(p-tolyl)hydrazineylidene)-pyrazole-1-carbothiohydrazide 21a displayed the highest antibacterial and antifungal activities with minimum inhibitory concentration (MIC) values lower than standard drugs chloramphenicol and clotrimazole, in the range of 62.5–125 and 2.9–7.8 µg/mL, respectively. View Full-Text
Keywords: pyrazole-1-carbothiohydrazide; 1,3,4-thiadiazines; hydrazonyl chlorides; antimicrobial activity; MIC pyrazole-1-carbothiohydrazide; 1,3,4-thiadiazines; hydrazonyl chlorides; antimicrobial activity; MIC

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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

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Radini, I.A.M. Design, Synthesis, and Antimicrobial Evaluation of Novel Pyrazoles and Pyrazolyl 1,3,4-Thiadiazine Derivatives. Molecules 2018, 23, 2092.

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