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A promising and useful method has been accomplished for regio‐ and diastereoselective synthesis of tetrahydro‐benzofuro[3,2‐c]chromenones through ceric(IV) ammonium nitrate (CAN) mediated oxidative coupling of cyclic/acyclic 1,3‐dicarbonyl compounds to 2‐aryl/heteroarylchromenes followed by a base assisted cyclization. The significant features of the method encircle easy accessibility of the starting materials, high air stability and low toxicity of oxidant CAN, high product yield, operationally simple and eco‐friendly reaction conditions. Trapping of a radical intermediate with radical scavenger TEMPO (detected by LC–MS) from the reaction mixture proved that the oxidative coupling is a radical mediated process. [ABSTRACT FROM AUTHOR]

A one-pot, three-component reaction between isatoic anhydride, 1,3-diketones, and amines/arylhydrazines catalyzed by a combination of molecular I2 and Et3N in open-air affords a series of quinazolin-4(3H)-one derivatives in good yield. The protocol offers an operationally simple, facile, and cost-effective pathway utilizing easily accessible reagents under mild reaction conditions with significant substrate scope. The results of steady state and time-resolved absorption and emission spectroscopy indicate the potential of quinazolin-4(3H)-one derivatives as a fluorescence probe. They exhibit unique photophysical responses in different solvent environments. In addition, they can also act as FRET acceptors during interaction with protein lysozyme. Preliminary biological studies indicate that quinazolin-4(3H)-ones are cell permeable and can be used as a fluorescent probe for bio-imaging of human cervical cancer (HeLa) cells. [ABSTRACT FROM AUTHOR]

A one‐pot, three‐component, and atom economic synthesis of biologically and pharmaceutically important fully substituted and functionalized pyrazole derivatives has been accomplished under metal‐catalyst‐free benign conditions. The strategy involves early condensation of readily available cyclic β‐diketones (dimidone, 4‐hydroxycoumarin and 2‐hydroxy‐1,4‐naphthoquinone) and arylglyoxals to generate a chalcone type intermediate which upon acid catalyzed condensation with ambident nucleophile arylhydrazones produces various aryl and cyclic β‐diketone substituted pyrazole derivatives. The synthesis embraces high functional group tolerance, broad substrate scope, excellent yield of the products, short reaction time and operationally simple and mild reaction conditions. The synthesis provides an easy opportunity of incorporating biologically important N‐diarylsulfide/selenide functionality, various enolisable cyclic β‐diketones and other bioactive heterocycles concurrently to pyrazole, which may help in designing and development of pyrazole derivatives of pharmacological significance. [ABSTRACT FROM AUTHOR]

A proline-based, chiral bi-functional organocatalyst containing both pyrrolidine and oxadiazolone heterocycle, has been successfully applied for stereoselective aldol reactions. The replacement of polar -COOH group of proline with bioisostere oxadiazolone ring provides excellent solubility of this catalyst in various organic solvents compared to low soluble proline. As a result, the organocatalyst effectively catalyzed the asymmetric condensation reaction between differently substituted aromatic aldehydes and various symmetrical and unsymmetrical ketones to produce the corresponding aldol products with excellent stereoselectivities (dr: 97:3, ee >99.9%) at room temperature in open-air. [ABSTRACT FROM AUTHOR]

Graphene oxide catalysed MW-assisted solvent-free synthetic route for the construction of densely substituted furan from simple starting materials has been reported. This green method offers a simple and highly effective strategy to synthesize a wide range of indole–furan and indole–pyrrole conjugates and bifuryl derivatives in one-pot operation. Moreover, graphene oxide, which is used for the first time in the synthesis of tetra-substituted furan, showed very high reactivity in this transformation and could be used in scalable synthesis. [ABSTRACT FROM AUTHOR]

A novel rhodamine-tryptamine conjugate-based fluorescent and chromogenic chemosensor (RTS) for detection of Hg2+ present in water was reported. After gradual addition of Hg2+ in aqueous methanol solution of RTS, a strong orange fluorescence and deep-pink coloration were observed. The probe showed high selectivity towards Hg2+ compared to other competitive metal ions. The 1:1 binding stoichiometry between RTS and Hg2+ was established by Job's plot analysis and mass spectroscopy. Initial studies showed that the synthesized probe RTS possessed fair non-toxicity and effectively passed through cell walls of model cell systems, viz., human neuroblastoma (SHSY5Y) cells and cervical cells (HeLa) to detect intercellular Hg2+ ions, signifying its utility in biological system. The limit of detection (LOD) was found to be 2.1 nM or 0.42 ppb by fluorescence titration. Additionally, the potential relevance of synthesized chemosensor for detecting Hg2+ ions in environmental water samples has been demonstrated.ᅟ [ABSTRACT FROM AUTHOR]