Synthesis and <i>in vitro</i> antibacterial evaluation of some thiosemicarbazides and thiosemicarbazones

Abstract

In the present study various thiosemicarbazides and thiosemicarbazones were synthesized and screened for their antimicrobial activity. Among the ligands tested, compounds 1, 3, 4 and 5 demonstrated inhibitory effects at 0.4 - 0.5 µM concentrations against <i>E. coli</i> while 1-(4-fluorobenzoyl)-N4-ethyl-thiosemicar-bazide (3) demonstrated the maximum inhibitory effective compound against <i>E. coli</i>, also possessing high water solubility. Instead, compound 3 demonstrated weak antibiotic effects against <i>S. aurous</i> while compounds 4 - 6 demonstrated significant antibacterial effects at 0.4 - 0.42 µM against the latter organism. Chloramphenicol was used as the positive control

New 3-hydroxy-2-naphthoic hydrazide derivatives: thiosemicarbazides and 1,2,4-triazole-3-thiones, their synthesis and in vitro antimicrobial evaluation

“…The thiosemicarbazide derivatives 1 and 2 substituted with aliphatic substituents: ethyl (1) and allyl (2) as well as compound 4 substituted with meta-methoxyphenyl showed the strongest activity among all of synthesized compounds. Ortho-methoxyphenyl and para-methoxyphenyl thiosemicarbazide derivatives (3,5) showed the weakest activity among all thiosemicarbazide derivatives. In the case of thiosemicarbazide (6) and 1,2,4-triazole derivative (12), the presence of 4-ethoxyphenyl substituent can be connected with the lack of antimicrobial activity.…”

“…1,2,4-Triazole derivatives (7)(8)(9)(10)(11)(12) were prepared in twostep synthesis. In the first step of synthesis, 3-hydroxy-2-naphthoic hydrazide was subjected to condensation reaction with appropriate isothiocyanates to afford 1,4-disubstituted thiosemicarbazide derivatives (1)(2)(3)(4)(5)(6). Then new 1,2,4-triazole-3-thiones (7)(8)(9)(10)(11)(12) were synthesized by the cyclization reaction of corresponding thiosemicarbazide (1-6) derivatives in alkaline media.…”

“…The synthesized compounds (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12) were screened in vitro for antibacterial and antifungal activity.…”

“…It is known that thiosemicarbazides act as antibacterial [3][4][5], antifungal [6,7], antitubercular [8], anticonvulsant [9,10] and antitumor agents [11,12]. In turn, the 1,2,4-triazoles display a broad range of biological activities, such as antibacterial [13][14][15][16][17][18][19], antifungal [20][21][22], antitubercular [23][24][25][26], antiviral [27] and antiproliferative properties [28][29][30].…”

Synthesis and Biological Evaluation of Some New Coumarin Derivatives as Antimicrobial Agents

“…On the other hand, literature survey revealed that thiosemicarbazones constitute one of the most versatile classes of compounds possessing antimicrobial and anti-amoebic activities [16][17][18][19][20] , depending on the nature of the substituents at N 1 and N 4 of thiosemicarbazone moiety. Various thiosemicarbazone derivatives have been successfully developed and documented as antimicrobial agents [16][17][18][19][20][21] .…”