Discovery of novel isatin-based thiosemicarbazones: synthesis, antibacterial, antifungal, and antimycobacterial screening

Abstract

Background and purpose: A group of thiosemicarbazones were prepared and their structures were confirmed by spectroscopic methods such as IR and H-NMR, mass spectrometry and also analytical method like elemental analysis. The synthesized semicarbazones were then assessed for their inhibitory activity against bacterial strains including Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus epidermidis, Bacillus cereus, Salmonella species, Enterobacter faecalis, methicillin-resistant Staphylococcus aureus , and fungi such as Candida albicans and Aspergillus niger . Experimental approach: The schiff bases of isatin ( 2a - j ) were prepared by a condensation reaction between thiosemicarbazide and substituted N-aryl isatins leading to the desired thiosemicarbazones with exquisite purity. Findings / Results: The results disclosed that all compounds have noticeable inhibitory activity. Compounds 2a , 2b , 2c , 2g , and 2h were among the most potent derivatives against Gram negative bacteria and fungi. Besides, the activity of theses compounds were tested against Mycobacterium bovis bacillus Calmette-Guerin ( M. bovis BCG). The antimycobacterial activity indicated compounds 2e and 2j are highly active against M. bovis BCG (minimum inhibitory concentration < 3.9 μg/mL). Among fluorinated structures, compounds 2a and 2j showed the best activities against M. bovis BCG. Conclusion and implications: To sum up, amongst the 10 synthesized compounds, fluorinated derivatives exhibited remarkable activities against both gram negative strains and candida albicans microorganism. Therefore, they should be considered as a clue for further modifications in next investigations. Furthermore, inserting a small/medium size halogen atom with electron-withdrawing and lipophilic properties increases anti- salmonella activity of these compounds and moreover 2-halogenated semithiocarbazones presented promising antimycobacterial activity.

5-Aryl-1-Arylideneamino-1H-Imidazole-2(3H)-Thiones: Synthesis and In Vitro Anticancer Evaluation

“…2.1. Chemistry 2-Arylhydrazinecarbothioamides 3a-e were prepared in high yield according to the reported procedure [18,19] through condensation of aromatic aldehydes (namely, benzaldehyde, 2-hydroxybenzaldehyde, 5-bromo-2-hydroxybenzaldehyde, 4-methoxybenzaldehyde 4-hydroxy-3-methoxybenzaldehyde, and cinnamaldehyde) with thiosemicarbazide in refluxing ethanol containing catalytic amounts of acetic acid. The structure of 3a-e was confirmed using different spectroscopic techniques.…”

Novel Thiosemicarbazone Derivatives from Furan-2-Carbaldehyde: Synthesis, Characterization, Crystal Structures, and Antibacterial, Antifungal, Antioxidant, and Antitumor Activities

“…However, 4 was less efective than the standard drugs Amphotericin B and Nystatin (MIC � 5 and 1-3 μg/mL, respectively). Compound 4 showed similar antifungal activity than the 2,3-dioxoindoline thiosemicarbazone derivatives (MIC � 30-60 μg/mL) tested against Candida albicans PTCC 5027 [63] and was more active than 1,3-bis-(2-carbaldehyde phenoxy) propan-2-ol ((MIC � 250 μg/mL) assayed against azole-sensitive Candida albicans ATCC 18804 [64]. Nevertheless, 2-((5-nitrothiophen-2-yl)methylene)-N-(pyridin-3-yl) hydrazine carbothioamide assayed against the Candida albicans ATCC 14053 strain was more efective (MIC � 4 μg/mL) [26] than 4.…”

Novel N-substituted indole hydrazones as potential antiplatelet agents: synthesis, biological evaluations, and molecular docking studies

“…Indole-3-carboxaldehyde derivatives (1a-c, 1.0 mmol) and suitable phenylhydrazines (1.3 mmol) were added to a mixture of absolute ethanol (10 mL) and glacial acetic acid (0.28 mL) ( 17 18 ). The ratio of ethanol to acetic acid was almost 33:1.…”