Harshad P. Lakum

Synthesis and biological evaluation of novel s-triazine based aryl/heteroaryl entities: Design, rationale and comparative study

Abstract The urgent need in search of new biological entities to fight back with recent drug-resistant microbial flora, has led us report a library of s-triazine derivatives. The intermediate 4-((4-chloro-6-methoxy-1,3,5-triazin-2-yl)amino)benzonitrile 3 was substituted with various thiophenol, phenol, aniline and piperazine/piperidine/morpholine moieties to furnish the final 35 target compounds i.e. (4a–j), (5a–j), (6a–g) and (7a–h), respectively. These compounds were screened for in vitro antibacterial evaluation against bacteria (Staphylococcus aureus MTCC 96, Bacillus cereus MTCC 619, Escherichia coli MTCC 739, and Pseudomonas aeruginosa MTCC 741) and antifungal activity against fungi (Candida albicans MTCC 183, Aspergillus niger MTCC 282, and Aspergillus clavatus MTCC 1323). The title compounds were further subjected for antituberculosis activity against Mycobacterium tuberculosis H37Rv strain using the BACTEC MGIT method. In this biological evaluation, thiophenol derivatives were found to be more active than the rest (i.e. -Thiophenol > -piperazine > -Aniline > -phenol). The final compounds were characterized by FT-IR, 1H NMR, 13C NMR, mass spectroscopy and elemental analysis.

Synthesis and in vitro antimicrobial evaluation of piperazine substituted quinazoline-based thiourea/thiazolidinone/chalcone hybrids

In frames of the search for new biological entities to fight against recent drug-resistant microbial strains, we report a library of quinazoline-based thiourea/4-thiazolidinone/chalcone hybrids. The newly synthesized compounds were studied for efficacy against several bacteria (Staphylococcus aureus, Bacillus cereus, Pseudomonas aeruginosa, and Klebsiella pneumoniae) and fungi (Candida albicans and Aspergillus clavatus) using the broth dilution technique. From the biological evaluation, (E)-3-(3,4-dimethoxyphenyl)-1-(4-((4-(4-ethylpiperazin-1-yl)quinazolin-2-yl)amino)phenyl)prop-2-en-1-one was found to be the most active analogue (microbial inhibition concentration 3.12 μg/mL) to inhibit the bacterial growth. The rest of the compounds showed equipotent efficacy (3.12–12.5 μg/mL) as compared to the standard. Final compounds were characterized by FT-IR, 1H NMR, 13C NMR, mass spectroscopy, and elemental analysis.

Synthesis, characterization, and antimicrobial screening of s-triazines linked with piperazine or aniline scaffolds

Abstract Two series of s-triazines linked with piperazine or aniline scaffolds (4a–i and 5a–j) were synthesized and evaluated for their in vitro biological efficacy against Gram positive and Gram negative bacteria (Klebsiella pneumoniae MTCC 109, Pseudomonas aeruginosa MTCC 741, Staphylococcus aureus MTCC 96, Bacillus cereus MTCC 619) and fungi (Candida albicans MTCC 183 and Aspergillus niger MTCC 282) using a broth dilution technique. Compounds most active against certain bacteria and fungi are 4e, 4g, 4i, 5d, and 5i.

Copper-mediated ligand-free Ullmann reaction approach to substituted s-triazines: rationale, synthesis, and biological evaluation

Abstract Two series of s-triazine derivatives were synthesized by copper-catalyzed Ullmann reaction. Facile route was adopted to achieve amination of s-triazines for the first time. The C-N coupling reactions were conducted in water under ligand-free and oxygen-free conditions. The synthesized compounds were screened for their in vitro antibacterial and antifungal activity. Compounds were further subjected to in vitro antitubercular screening against the H37Rv strain. Compared with standard drugs, compound 5b was found to be the most active antimicrobial and antitubercular agent that inhibits Staphylococcus aureus and H37Rv strain with minimum inhibitory concentration of 1.56 and 6.25 μg/mL, respectively.