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The present work describes an efficient and environmentally benign four component synthesis of structurally diverse substituted pyrido-pyrimidines involving the reaction of barbituric acid, 4-hydroxy 6-methyl 2-pyrone, an aromatic aldehyde and ammonium acetate in low transition temperature mixture (LTTM) (glycerol:proline: 1:1). The LTTM serves as green solvent which is an inexpensive, nontoxic and plays a dual function (reusable catalyst and solvent), and is found to be an excellent reaction endorsing medium. The present protocol offers some advantages such as easy work up, shorter reaction time, an excellent yield with higher atom economy, maximum reaction efficiency with an excellent green chemistry metrics. The synthesized compounds have been evaluated for their antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay as well as molecular docking studies performed on myeloperoxidase enzyme. Tested scaffolds exhibits an excellent results of virtual screening and antioxidant activity. [ABSTRACT FROM AUTHOR]

One pot three component reaction of 4‐hydroxy‐6‐methylpyran‐2‐one, 3‐methoxy benzaldehyde, and malononitrile in water using protic ionic liquid as a catalyst at room temperature afforded pyrano[4,3‐b]pyran derivatives. Protic ionic liquid has been proved to be an efficient and mild catalyst for the synthesis of pyrano[4,3‐b]pyran scaffolds due to their highly polar nature. The notable aspects of protic ionic liquid are easy availability, improved reaction rates, high product yields, simple workup procedure, recyclability, and reusability. Molecules docking studies have been performed on enzyme enoyl‐ACP‐reductase from Mycobacterium tuberculosis. The molecular docking simulation indicated plausible π‐alkyl and alkyl‐alkyl interactions between the amino acids and scaffolds. The synthesized derivatives have been evaluated for their in vitro antituberculotic activity against M. tuberculosis H37RV strain using Microplate Alamar Blue Assay method. Together, biological activity data and docking data showed that the tested scaffolds exhibited excellent antituberculotic activity. [ABSTRACT FROM AUTHOR]

A highly competent synthesis of novel 7‐aryl‐10‐thioxo‐7, 10, 11, 12‐tertahydro‐9H‐benzo [H] pyrimido [4, 5‐b] quinoline‐8‐one derivatives has been reported through a Knoevenagel condensation followed by Michael addition and subsequent cyclization using ethanol:acetic acid (8:2 v/v). The mentioned protocol has advantages like high yields, cleaner reactions, operational simplicity, and environment friendliness. Moreover, these compounds were further screened against the plant pathogenic fungi like Colletotrichum truncatum, Ustilago maydis, Trichosporon, Trichothecium sp., Aspergillus oryze, Aspergillus terreus, and Aspergillus niger by agar well method bioassay. The results were elaborated for minimum inhibitory concentration determination using agar dilution method against fungal strains C. truncatum and U. maydis as well as broth dilution method for bacteria species Gram‐positive Bacillus megaterium and Gram‐negative Proteus vulgaris. Most of the tested compounds showed promising results towards the antimicrobial activity. [ABSTRACT FROM AUTHOR]

An efficient green protocol has been investigated for the synthesis of pyrimido[4,5-b]quinolines derivatives via one-pot three-component condensation of 4-chloro aniline, aromatic aldehyde and barbituric acid using low transition temperature mixtures as new generation and sustainable solvents. The process was accomplished with the use of greener and recyclable reaction media, simple methodology, easy workup procedures and no chromatographic purification with high yield. This new approach is expected to discover some significance in combinatorial synthesis of biologically active scaffolds. Graphical Abstract: [ABSTRACT FROM AUTHOR]

A series of novel 7-(3-chloro-phenyl)-10-thioxo-7,9,10,11-tetrahedro-6 H-pyrimido-[5′4′:5,6] pyrano[3,2-c]quinoline-6,8(5 H)-dione derivatives have been synthesized through the multi-component condensation of aromatic aldehydes, barbituric acid, and 2,4-dihydroxy quinoline, using heterogeneous sulfamic acid catalyst in water-ethanol (4:1) solvent system under reflux condition. The present protocol is endowed with charming description such as green synthetic procedure, short reaction time, easy work-up procedure, and excellent yield and high atom economy of pyranoquinoline derivatives. In this study, sulfamic acid is used as a heterogeneous catalyst that is easily recoverable and recyclable. The proposed multi-component reaction has been studied with detail mechanism and spectroscopic data. This is one of the potential greener synthetic approaches to build up the series of pyranoquinoline heterocycles. [ABSTRACT FROM AUTHOR]

A series of novel 7-phenyl-7,12-dihydrobenzo( h)pyrido[2,3- b]naphthydrin-6(5 H)-one were synthesized by a one-pot three-component condensation of 2,4-dihydroxyquinoline, 2-amino pyridine and various aromatic aldehydes with sulfamic acid as an enviro-economic catalyst. The salient features of this method consist of high atom economy and yields, short reaction time, non-carcinogenic solvents, and chromatography-free work-up procedure. Fascinatingly, the catalyst can be reused for up to four cycles giving good to excellent yields. By employing this method, a series of 14 pyrido[2,3- b]naphthydrin compounds were synthesized. This procedure is projected as a green avenue in the combinatorial synthesis of biologically active naphthydrin derivatives. Graphical Abstract: [ABSTRACT FROM AUTHOR]

An uncatalyzed efficient synthesis of bioactive pyridine derivatives has been investigated for the first time by a three-component sequential multicomponent reaction tackled with aromatic aldehydes, malononitrile, and 1,3-indandione via Knoevenagel condensation followed by Michael addition. The difference between the domino multicomponent and sequential multicomponent reaction is emphasized by this methodology. The reaction proceeds at ambient temperature without frequently useful N-source like ammonium salt for the construction of N-heterocycles, which makes this protocol a novel synthetic route for the preparation of the indenopyridine skeleton. Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

A highly competent-diversity oriented synthesis of coumarin core derivatives using a Knoevenagel condensation followed by Michael addition and subsequent cyclization in the presence of (±)-camphor-10-sulfonic acid in a water/ethanol (1:1) solvent system is depicted. Furthermore, easy workup procedures with good yield, rapid reactions with high atom economy, and catalyst recyclability are the fascinating features of the procedure. [ABSTRACT FROM AUTHOR]

The present study describes an alkalinewater–ethanol mediatedseries of combinatorial synthesis of 2-amino-4-phenyl-5-H-indeno[1,2d]pyrimidine-5-one derivatives throughsequential multicomponent reaction of 1,3indandione, aromatic aldehydes,and guanidine hydrochloride along with their anticancer evaluation.The effect of sequential addition of the components in the configurationof the desired product has been studied by UV–visible absorptionspectroscopy. The synthetic method obeys most of the green chemistryprinciples in regard to high atom economy and greener, nontoxic, andnoncarcinogenic solvent system (water–ethanol). The selectedsynthesized compounds have been screened against the human breastcancer cell line MCF7, human colon cancer cell line HT29, and normalviro monkey cell line, out of which 2-amino-4-(4-methoxyphenyl)-5H-indeno[1,2-d]pyrimidin-5-one showedsignificant potency toward human breast cancer cell line (MCF7). [ABSTRACT FROM AUTHOR]