نتایج جستجو برای: ketoesters
تعداد نتایج: 289 فیلتر نتایج به سال:
A family of Schiff bases was synthesized by the reactions of o-aminobenzoic acid and Knovenegal condensate of β-ketoesters in 1:1 ratio. The newly synthesized Schiff bases were characterized by Elemental analyses and spectral (FT-IR, UV–Vis and H-NMR) studies and the structures have been proposed tentatively. These compounds were subjected to study their biocidal efficacy against S. epidermidis...
A novel NHC-catalyzed three-component domino strategy to access high functionalized cis-ε-ketoesters with excellent yields (up to 98%) and high stereoselectivities (up to 20:1) is documented. The title domino reactions are atom economical and work on a broad range of substrates. The relative stereochemistry could be explained by a cascade crossed-benzoin/oxy-Cope rearrangement/esterification pr...
A general and efficient phosphorous acid-catalyzed cyclocondensation of β-ketoesters with o-aminobenzamides via selective C-C bond cleavage leading to quinazolinones is developed. This reaction proceeds smoothly under metal- and oxidant-free conditions, giving both 2-alkyl- and 2-aryl-substituted quinazolinones in excellent yields. This strategy can also be applied to the synthesis of other N-h...
The fragmentation reaction of differently functionalized [2.2.2]- and [2.2.1]bicyclic systems that leads to substituted five membered heterocycles and five/six membered carbocycles is broadly studied. This reaction is carried out through a retro-Dieckmann-type condensation on strained [2.2.1]bicyclic β-ketosulfones and their counterparts β-ketoesters under very mild catalytic acid or basic cond...
Some 2-hydroxy-4-methyl-6substituted quinoline derivatives have been synthesized in an environmentally benign method from easily available 4-substituted anilines and β-Ketoesters, under ordinary conditions. The reactions were catalyzed by aluminium chloride to afford excellent amount of the products. The usage of hazardous acids, bases and solvents have been avoided in different steps of the re...
A new organocatalytic asymmetric domino Michael-alkylation reaction of methyleneindolinones and γ-halogenated-β-ketoesters is described. A variety of spiro-cyclopentanoneoxindoles were obtained in high yields (up to 96%), good diastereoselectivities (up to 12 : 1 dr) and excellent enantioselectivities (up to >99% ee) via α-alkylation. Interestingly, O-alkylated products with tetronic acid motif...
We report here an efficient and green method for Biginelli condensation reaction of aldehydes, β-ketoesters and urea or thiourea catalyzed by Brønsted acidic ionic liquid [Btto][p-TSA] under solvent-free conditions. Compared to the classical Biginelli reaction conditions, the present method has the advantages of giving good yields, short reaction times, near room temperature conditions and the ...
The copper-catalyzed α-amination of carbonyl compounds using nitrosoformate intermediates as the electrophilic source of nitrogen is reported. The reaction merges aerobic oxidation and Lewis acid catalysis. The scope of the reaction is broad in terms of both the N-substituted hydroxylamines and the β-ketoesters. The new methodology harnesses the power of nitrosoformate intermediates and demonst...
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