A highly functionalized 9,9-disubstituted (phenylethynyl)-fluorene-appended -methyl-7-azaindole derivatives has been synthesized from various fluorene propargylic alcohols and substituted-7-azaindoles using BFOEt as a catalyst. The scope of the reaction was demonstrated by selecting a range of fluorene propargylic alcohols and substituting 7-azaindoles. A plausible reaction mechanism for forming title compounds via propargylic carbocation is postulated.
View Article and Find Full Text PDFA catalyst-free and green chemical method has been developed for the methylenation of indole and -methyl-7-aza indoles with aqueous formaldehyde afforded respective ,'-dimethyl-3,3'-bis-7-azaindolylmethanes under microwave irradiation in excellent yield. Subsequent oxidation of the products thus obtained, using one electron chemical oxidant CAN afforded ,'-dimethyl-3,3'-bis-7-azaindolylmethanone derivatives in excellent yield. This resulted in methanone derivatives with halogen substitution at the aryl ring which when subjected to Suzuki coupling with aryl boronic acids furnished highly functionalized fluorescent biaryl derivatives.
View Article and Find Full Text PDFA facile and efficient method has been developed for the synthesis of quinoline-fused fluorescent dihydro/spiro-quinazolinones. A plausible mechanism involving an acid-mediated enaminone intermediate is provided. The reaction proceeded using -toluene sulfonic acid as a green promoter.
View Article and Find Full Text PDFA mixture DMSO-allyl bromide has been developed as a reagent for an atom economic one-pot -allylation and aryl bromination under basic conditions. Utilizing this reagent, -allylation-bromination of a number of 2°-aryl amines, aryl aminoamides, indoles, and 7-aza indoles has been achieved. The scope of the substrates and limitations, the synthetic utility of the products, and a plausible reaction mechanism have been proposed.
View Article and Find Full Text PDFSynthesis of spiroindoloquinazolines via one-pot three-component condensation reactions of tryptanthrin, malononitrile or ethylcyanoacetate, and nucleophiles was carried out in MeOH using triethylamine as the base catalyst under reflux conditions. This method has the advantages of short reaction time, excellent yields, and an easy work-up procedure. The structural properties of the compound {2-amino-6-methyl-spiro-[12]Indolo(2,1-)quinazoline-12-one]12',4-pyrano(2,3-)pyrazole]-3-carbonitrile} and the obtained crystal were analyzed by the DFT theoretical calculation method, using the B3LYP 6-311G(d,p) basis set and were found to be in agreement with the experimental results.
View Article and Find Full Text PDFChromones are the class of secondary metabolites that broadly occur in the plant kingdom in a noticeable quantity. This rigid bicyclic system has been categorized "as privileged scaffolds in compounds" in medicinal chemistry. Their wide biological responses have made them an important moiety in a drug discovery program.
View Article and Find Full Text PDFA facile and diversity-oriented approach has been developed for the synthesis of pyrrole-, pyridine-, or azepine-appended (het)aryl aminoamides via the -allylation/homoallylation-ring-closing metathesis (RCM) strategy. Microwave condition was efficiently utilized for -allylation of (het)aryl aminoamides to synthesize di-, tri-, and tetra-allyl/homoallylated RCM substrates in good yields. All of the RCM substrates were successfully converted to respective pyrroles , ,, ,, pyridines , , and azepines , via RCM.
View Article and Find Full Text PDFNaN3-ROH/ArOH has been found to be an efficient reagent for 1,3-amino alkoxylation and 1,3-amino phenolation of a maleimide-derived MBH adduct of isatin via domino azidation-Michael addition. Following this protocol, with NaN3-formalin, a one-pot synthesis of 3-spiro-1,2-dihydropyrrolooxazine-5,7-dione-oxindole has been achieved. In an aprotic medium, the reaction underwent an unusual amino dimerization via an aza-Diels-Alder reaction of a common allylic imine intermediate.
View Article and Find Full Text PDFA facile method utilizing RCOX/K2CO3 as a novel reagent for conjugate addition of hydrogen halide, in addition to tertiary (3°)-hydroxyl protection that leads to the synthesis of functionalized β-halo Morita-Baylis-Hillman ester appended oxindoles, has been developed. The diastereoselective one-pot O-acylation-hydrohalogenation observed cannot otherwise be performed by treatment with hydrohalide. Deprotection of a 3°-hydroxyl protecting group has also been demonstrated by treatment with hydrochloric acid.
View Article and Find Full Text PDFUnlabelled: Common effluent treatment plant (CETP) for tannery effluent, is the combination of physical, chemical and biological treatment to facilitate the degradation of industrial waste water. Obviously, the biomass which survives in this extreme environment may have the ability to utilize the effluent as the sole carbon source for its survival. The ultimate aim of the present investigation is to expose the microbial diversity in each stage of the CETP through the culture dependent way.
View Article and Find Full Text PDFA facile and efficient binary Cu(I)/Cu(II) catalyzed one-pot, three-component synthesis of 2-amino-3-iminoethenylidene-2-indolones in excellent yield has been achieved. Remarkably, these newly synthesized, stable merocyanine dye analogues showed strong luminescence in the blue region with large Stokes shifts.
View Article and Find Full Text PDFActivated alkene dependent one-pot, three-component aza-Morita-Baylis-Hillman (aza-MBH) reaction of ferrocenealdehyde afforded simple aza-MBH adduct of ferrocenealdehyde, unusual piperidine, β-amino acid residue, and γ-ketoester derivatives of ferrocene in good yield. The synthetic protocol with MVK has led to an unexpected ferrocenyl piperidine derivative in an excellent yield via diastereoselective domino aza-Michael/double Aldol pathway. Plausible mechanisms for the formation of unusual products and diastereoselectivity have also been described.
View Article and Find Full Text PDFAn activation of the pyridine nucleus has been achieved via 1,5-electrocyclization of vinyl pyridinium ylides generated from bromo isomerized Morita-Baylis-Hillman adducts of isatin and pyridine under basic conditions. The method has been successfully applied for an efficient synthesis of a number of 3-spirodihydroindolizine-2-oxindoles, which have been found as core structure of secoyohimbane and heteroyohimbane alkaloid natural products.
View Article and Find Full Text PDFThe chemistry phosphorus and sulfur ylides have been exploited for a facile, short and efficient synthesis of 3-spirocyclopentene- and 3-spiropyrazole-2-oxindoles from E- and Z-isomers of bromo derivatives of Morita-Baylis-Hillman adducts of isatin with Ph(3)P/activated alkene/K(2)CO(3) and Me(2)S/DEAD/K(2)CO(3), respectively, via [3 + 2]-annulation strategy.
View Article and Find Full Text PDFA novel regioselective synthesis of a number of functionalized 3-spiropyrrolizidine and 3-spiropyrrolidine oxindoles from Baylis-Hillman adducts of isatin and heteroaldehydes via [3+2] cycloaddition of azomethine ylides in excellent yields has been reported.
View Article and Find Full Text PDF[reaction: see text] A novel and powerful reagent system R(3)Al-R'(3)SiOTf for the one-pot alkylation-silylation reaction of epoxides was discovered, and the reactions of various epoxides with the new reagent system have been demonstrated to occur stereospecifically giving rise to the corresponding alkylation-silylation products in excellent yields.
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