Bhupendra M. Mistry

Synthesis and in vitro antimicrobial and anti-tubercular evaluation of some quinoline-based azitidinone and thiazolidinone analogues

Keeping the objective to build up a new structural class of potent antimicrobials and antituberculosis agents, a series of potentially active quinoline-based azetidinone and thiazolidinone analogues has been synthesized by a simple and efficient synthetic protocol. The thione nucleus formed from 2-chloroquinoline-3-carbaldehyde using sodium sulphide in DMF followed by reaction with various substituted amine to form the corresponding Schiff base intermediates. Attempt has been made to derive final azetidinone and thiazolidinone analogues from Schiff bases by using chloroacetyl chloride and 2-mercapto acetic acid, respectively. Newer analogues were characterized by IR, 1H NMR, 13C NMR spectroscopy and elemental analyses. The newly synthesized analogues were then examined for their antimicrobial activity against some bacterial and fungal strains as two Gram −ve bacteria (Escherichia coli MTCC 739, Pseudomonas aeruginosa MTCC 741), two Gram +ve bacteria (Staphylococcus aureus MTCC 96, Bacillus subtilis MTCC 430) and two fungal species (Aspergillus niger MTCC 282, Candida albicans MTCC 183) to develop a novel class of antimicrobial agents and The final compounds were tested for in vitro antituberculosis activity against Mycobacterium tuberculosis. Streptomycin, Isoniazid, Rifampicin and Ethambutol were used as standards in this test. These observations provide some predictions to design further antibacterial and antituberculosis active compounds prior to their synthesis according to molecular modeling studies.

CORROSION INHIBITION OF MILD STEEL IN 1 N HCL SOLUTION BY MERCAPTO-QUINOLINE SCHIFF BASE

Corrosion inhibition of mild steel in 1 N HCl solutions was investigated in the absence and presence of different concentrations of some mercapto-quinoline derivatives namely, 3-((phenylimino)methyl)quinoline-2-thiol (PMQ) and 3-((5-methylthiazol-2-ylimino)methyl)quinoline-2-thiol (MMQT) by using conventional weight loss, potentiodynamic polarization, linear polarization, electrochemical impedance spectroscopy, and scanning electron microscopic studies. By EIS and weight loss measurements, it was found that PMQ and MMQT were effective inhibitors and their inhibition efficiency was significantly increased with increasing concentrations of inhibitors. Polarization curves showed that the evaluated PMQ and MMQT both act as mixed inhibitions. The adsorptions of these inhibitors on the mild steel were found to follow the Langmuir adsorption isotherm. Results show that the rate of corrosion of mild steel increased with increasing temperature over the range 25°–45°C both in the presence of inhibitors and in their absence. Activation energies in the presence and absence of PMQ and MMQT were obtained.

Quinoline-based azetidinone and thiazolidinone analogues as antimicrobial and antituberculosis agents

New azetidinone and thiazolidinone class of bioactive agents based on quinoline nucleus have been synthesized. 2-Chloroquinoline-3-carbaldehyde reacted with various substituted amine to form the corresponding Schiff base intermediates. We have derived final azetidinone and thiazolidinone analogues from Schiff bases using chloroacetyl chloride and 2-mercaptoacetic acid, respectively. The newly synthesized analogues were then examined for their antimicrobial activity against some bacterial and fungal strains as two gram −ve bacteria (Escherichia coli MTCC 739 and Pseudomonas aeruginosa MTCC 741), two gram +ve bacteria (Staphylococcus aureus MTCC 96 and Bacillus subtilis MTCC 430), two fungal species (Aspergillus niger MTCC 282 and Candida albicans MTCC 183) as well as against Mycobacterium tuberculosis strain H37Rv to develop a novel class of bioactive agents. The results of bioassay showed that some of the newly synthesized azetidinones and thiazolidinones emerged as lead molecules with excellent MIC (mg/mL) values against mentioned microorganisms compared to standard drugs. The structure of the final analogues has been confirmed on the basis of IR, 1H NMR, 13C NMR, and elemental analysis.

Synthesis and Evaluation of Some Quinoline Schiff Bases as a Corrosion Inhibitor for Mild Steel in 1 N HCl

This article has been retracted.