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This work focuses on the rapid synthesis of Schiff bases with green protocols, where P2CA (Pyridine‐2‐carboxylic acid) is utilized as a catalyst. The condensation reaction of aldehydes and anilines, facilitated by P2CA, resulted in the production of Schiff bases in good to excellent yield within a remarkably short time of up to 15 min. The electronic effect of the various substituents on aldehyde and aniline, in combination with the catalytic effect of P2CA, accelerated the reactions under mild conditions. The reusability of the catalyst was thoroughly examined, and the catalyst was characterized over every cycle. Importantly, this approach is not only green and sustainable, but also cost‐effective, harmless, and environmentally friendly, thanks to the affordability and benign nature of P2CA. [ABSTRACT FROM AUTHOR]

Herein, a solvent-free synthesis of 5-bromothiophene based 3,4-dihydropyrimidin-2-(1H)-(thi)ones was explored. The main advantages of this study are that pure products are readily obtained through an easy workup and without using any separation technique and in good yields (66-80% yield), All the synthesized products were characterized by 1H and 13C-APT NMR, IR spectroscopy and elemental analysis. A single crystal X-ray analysis of ethyl-4-(5-bromothiophen-2-yl)-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate (4c) was performed. All the synthesized compounds were screened for their antifungal and antibacterial assay. Among all synthesized compounds, some showed good antibacterial and antifungal activity. ADMET prediction for was carried out and calculated data show that all the compounds have a drug-like nature. [ABSTRACT FROM AUTHOR]

A one-pot procedure for the preparation of functionalized 1,4-dihydropyridines by three-component reaction using substituted heterocyclic aldehydes, ammonium acetate, and substituted β-ketoesters catalyzed by L-proline was described. Present protocol offers excellent yield up to 92%, flexibility with different substitution, convenient operation, and eco-friendliness. The synthesized products were confirmed by 1H-NMR, 13C-APT, and IR spectroscopy. Herein, final confirmation of the targeted motif was made by X-ray single-crystal analysis of representative compounds (4f, 4j, 4k, 4l, and 4o). The chemically synthesized compounds were evaluated for the antiproliferative activity by cell viability (MTT) assay and dual AO/EB (acridine orange/ethidium bromide)-staining method against human A549 lung cancer cell lines. The viability of the treated cell was evaluated adopting MTT assay. According to associated changes in cell membranes during the process of apoptosis, a clear difference was observed between normal cells, early and late apoptotic cells, and necrotic cells. All compounds were found effective against Saccharomyces cerevisiae which was confirmed by increased reactive oxygen species production and DNA damage as compared to untreated yeast cell culture. Altogether, these compounds showed promising hope for application in pharmaceutical aid against yeast infections. [ABSTRACT FROM AUTHOR]

Herein, we established a straightforward synthetic route for biological relevant [1,2,4]triazolo[5,1‐b]quinazolin‐8(4H)one scaffolds using the group‐assisted purification (GAP) chemistry via one‐pot and three component reaction of 3‐Amino‐5‐methylthio‐1H‐1,2,4‐triazole (1), Aryl aldehyde(2 a–g), and 1,3‐cyclodione (3 a–b) using L‐proline and aqueous ethanol (1:1, v/v) as green catalyst and reaction media respectively. This work shows some key features such as practical low Environment factor (E‐factor) values, excellent atom economy, reaction mass efficiency, mild reaction condition, metal‐free synthesis, and no use of column chromatography. In preliminary biological screening, the compounds, 2‐(methylthio)‐9‐(4‐nitrophenyl)‐5,6,7,9‐tetrahydro‐[1,2,4]triazolo[5,1‐b]quinazolin‐8(4H)‐one (4 i) and 6,6‐dimethyl‐2‐(methylthio)‐9‐(pyridin‐4‐yl)‐5,6,7,9‐tetrahydro‐[1,2,4]triazolo[5,1‐b]quinazolin‐8(4H)‐one (4 l) were found most potent against Gram‐negative bacteria (E. coli) than the standard drugs ampicillin and chloramphenicol. Moreover, compounds 2‐(methylthio)‐9‐phenyl‐5,6,7,9‐tetrahydro‐[1,2,4]triazolo[5,1‐b]quinazolin‐8(4H)‐one (4 a) and 9‐(4‐methoxyphenyl)‐6,6‐dimethyl‐2‐(methylthio)‐5,6,7,9‐tetrahydro‐[1,2,4]triazolo[5,1‐b]quinazolin‐8(4H)‐one (4 f) exhibited excellent potency in comparison with the standard drugs ampicillin, chloramphenicol, and ciprofloxacin against Gram‐positive bacteria (S. aeruginosa and S. pneumoniae). In antifungal screening compounds, 9‐(4‐methoxyphenyl)‐2‐(methylthio)‐5,6,7,9‐tetrahydro‐[1,2,4]triazolo[5,1‐b]quinazolin‐8(4H)‐one (4 e) and 2‐(methylthio)‐9‐(4‐nitrophenyl)‐5,6,7,9‐tetrahydro‐[1,2,4]triazolo[5,1‐b]quinazolin‐8(4H)‐one (4 i) efficiently inhibited C. albicans fungi strain than that of standard drug griseofulvin. Noteworthy compounds 6,6‐dimethyl‐2‐(methylthio)‐9‐phenyl‐5,6,7,9‐tetrahydro‐[1,2,4]triazolo[5,1‐b]quinazolin‐8(4H)‐one (4 b), 9‐(4‐chlorophenyl)‐6,6‐dimethyl‐2‐(methylthio)‐5,6,7,9‐tetrahydro‐[1,2,4]triazolo[5,1‐b]quinazolin‐8(4H)‐one (4 d), and 2‐(methylthio)‐9‐(pyridin‐4‐yl)‐5,6,7,9‐tetrahydro‐[1,2,4]triazolo[5,1‐b]quinazolin‐8(4H)‐one (4 k) were exhibited better potency against M. Tuberculosis. Synopsis By holding the green chemistry concept, we explored one‐pot synthesis [1,2,4]triazolo[5,1‐b]quinazolin‐8(4H)one scaffolds. Moreover, all the newly synthesized compounds were tested for their antimicrobial and anti tuberculosis activities. Noteworthy, majority of compounds were exhibited better antimicrobial and anti tuberculosis activities. [ABSTRACT FROM AUTHOR]