Abstract
A series of 3-acetyl-2-aryl-5-methylthio-2,3-dihydro-1,3,4-thiadiazoles 3a–g, N- (4-acetyl-5-aryl-4,5-dihydro-1,3,4-thiadiazol-2-yl) acetamide derivatives 5a–e and spiro-compound 7 was prepared from starting material dithiocarbazates using N-methylpyrrolidone (NMP) /acetic anhydride mixture. Furthermore, a new series of 5-amino-3- (methylthio) -1-substituted-1H-pyrazole-4-carbonitrile derivatives 12a–d was prepared using two synthetic routes: (i) via reaction of bis (methylthio) methylene malononitrile 8 with carbothiohydrazides 11a–d, or (ii) via reaction of methyl 5-amino-4-cyano-3- (methylthio) -1H-pyrazole-1-carbodithioate 9a with primary/secondary amines. The antimicrobial screening of newly synthesized compounds revealed that compounds 3b, 7, and 12d are the most potent against the Gram-positive (S. aureus) and the Gram-negative (E. coli) bacteria compared to ciprofloxacin as reference drug. Mechanistically, the theoretical docking results of 3b, 7 and 12d suggested that they may act as potent inhibitors of theDNA gyrase.
Graphical Abstract
![](/cms/asset/3c3ab8a6-b8d5-4dff-b77c-3777838249ae/lsyc_a_1843179_uf0001_c.jpg)
Acknowledgments
The authors thank Dr. EsamRashwan, Head of the confirmatory diagnostic unit VACSERA, Egypt, for carrying out the in-vitro antimicrobial screening. This research did not receive any specific grant from any funding agencies.
Disclosure statement
No potential conflict of interest was reported by the author (s).