Green One-pot Synthesis of Novel Polysubstituted Pyrazole Derivatives as Potential Antimicrobial Agents

Abstract

Various biological properties of natural and synthetic pyrazole derivatives such as anti-inflammatory, antimicrobial, neuroprotective, anticonvulsant, antidepressant and anticancer activities encouraged us to propose a new, fast, green and eco-friendly procedure for the preparation of some novel 5-amino-3-(aryl substituted)-1-(2,4-dinitrophenyl)-1H-pyrazole-4-carbonitriles. They were efficiently synthesized via one-pot two-step process reaction of malononitrile, 2,4-dinitrophenylhydrazine and different benzaldehydes in deep eutectic solvent (DES) glycerol/potassium carbonate. The products yield and reaction times were considerably improved in the presence of applied DES. Antibacterial effects of all newly synthesized pyrazoles in comparison with several common antibiotics were evaluated against a variety of Gram-positive and Gram-negative pathogenic bacteria. In addition to, their inhibitory activities on three fungi were compared to some current antifungal agents. The moderate to good antimicrobial potentials particularly against fungi were observed in the major heterocyclic compounds according to the IZD, MIC, MBC and MFC results.

Synthesis, Characterization and Antimicrobial Evaluation of Novel 6’-Amino-spiro[indeno[1,2-b] quinoxaline[1,3]dithiine]-5’-carbonitrile Derivatives

“…Antimicrobial properties including broth microdilution and time-kill susceptibility were tested based on the IZD, MIC, MBC and MFC values according to the CLSI (the clinical and laboratory standards institute) guidelines M07-A9, M26-A, M02-A11, M44-A and M27-A2. 17,[22][23][24] Gram-negative pathogenic bacteria including Pseudomonas aeruginosa (PTCC 1310), Escherichia coli (PTCC 1399), and Salmonella enterica subsp. enterica (PTCC 1709); Gram-positive strains including Staphylococcus aureus (PTCC 1189) and Staphylococcus epidermidis (PTCC 1435); fungi including Fusarium oxysporum (PTCC 5115) were prepared from the Persian Type Culture Collection (PTCC), Tehran, Iran.…”

Greener and Environmentally Benign Methodology for the Synthesis of Pyrazole Derivatives

“…Another catalyst free synthesis is developed by Daniela Vuluga et al [90] by the 1,3 dipolar cycloaddition of diazo compound to alkynes gives pyrazole (78) in presence of heating at 80°C in 1 hr gives 95 % yield. This protocol is very green due to without use of catalyst and solvent afforded excellent yield within short period of time that reduces use of toxic chemicals and pollution also (scheme 77).…”

“…Hamid Beyzaei et al [78] . carried out green synthesis of polysubstituted pyrazoles (63) and study their antimicrobial activities in presence of deep utectic solvent (DES).…”

Multicomponent Solvent-Free Synthesis, Antibacterial Evaluation and QSAR Study of 2-(Bis(benzylthio)methylene) malononitriles

“…lines M07-A9, M26-A and M02-A11. 33 The stock solutions of all derivatives and antibiotics were respectively prepared in 10% DMSO and double-distilled water at concentrations of 10240 and 17.6 mg mL -1 . The IZD values were measured at these initial concentrations.…”