Characterization and Antimicrobial Studies of Five Substituted Bis-Thioureas

Abstract

Thioureas play an important role in medicinal chemistry and agricultures due to their biological activity such as antibacterial, antifungal, antiviral, herbicides, rodenticides, phenoloxidase enzymatic inhibitors, anti-HIV and anti-tumor agents. In this study, five substituted bis-thioureas have been synthesized. The isophataloyl chloride and 2,6-pyridinedicarbonyl dichloride were easily converted to bis-isothiocyanate compound via the reaction with ammonium thiocyanate by solid-liquid phase transfer catalysis of polyethylene glycol-400 (PEG-400). Bis-isothiocyanate compound was reacted with aniline derivatives to produce substituted bis-thioureas in good yield at room temperature. All the novel compounds were obtained as yellow solid after recrystallization using DMF/EtOH/H 2 O. Their c h e m i c a l structures were confirmed by Infrared spectrosopy (IR), Nuclear Magnetic Resonance (NMR) 1 H and 13 C and mass spectrometry. The five synthesized compounds were screened for antimicrobial activities using disc diffusion method for antimicrobial activity against Gram-positive bacteria (Bacillus Subtilis and Staphylococcus Aureus), Gram-negative bacteria (Escherichia Coli and Salmonella Typhi) and a mold (Aspergillus Niger). All tested compounds showed low antimicrobial activity since the diameter of inhibition zone (IZ) measure was less than positive control inhibition zone.

Recent developments in chemistry, coordination, structure and biological aspects of 1-(acyl/aroyl)-3-(substituted) thioureas

“…The compounds failed to exhibit any pronounced activity that may be ascribed to their solubility on the agar surface. However, pyridine-based bis-thiourea 47 showed significant antibacterial activity owing to their enhanced lipophilic character due to triflouro methyl substituents [152].…”