نتایج جستجو برای: aldol condensation
تعداد نتایج: 33583 فیلتر نتایج به سال:
A core 4,5,6,7-tetrahydroisoxazolo[4,3-c]pyridine-4-one scaffold is elaborated at C-3(Me) by base-mediated aldol condensation to give new 3-alkenyl-4,5,6,7-tetrahydroisoxazolo[4,3-c]pyridine-4-ones, which are masked forms related to the acylpyridone natural products.
A highly diastereoselective tandem ring-enlargement and aldol condensation process involving multicomponent reactions of ethereal tricyclooxonium ylide intermediate with alcohols, mono- or dialdehydes in the presence of titanium(iv) isopropoxide is described to furnish alkoxyoctahydro-1,4-benzodioxocin-6(5H)-one ring systems.
Yolk-shell TiO2 microspheres were synthesized via a one-pot template-free solvothermal method building on the aldol condensation reaction of acetylacetone. This unique structure shows superior light scattering ability resulting in power conversion efficiency as high as 11%. This work provided a new synthesis system for TiO2 microspheres from solid to hollow and a novel material platform for hig...
N-Nitrosobis(2-oxopropyl)amine, a potent carcinogen for the pancreas in Syrian hamsters, undergoes a facile, base-catalyzed, intramolecular aldol condensation to yield N-nitroso-5-hydroxy-5-methyl-3-piperidone. This cyclic nitrosamine then decomposes to yield 3-hydroxy-5-methylpyridine.
The aldol condensation of model compounds furfural and acetone on the selected base catalysts have been performed. The activity of MgO was compared with industrially produced hydrotalcite and the series laboratory prepared hydrotalcites. Si×MAl2O4 hydrotalcites (M = Mg, Zn, Ni, Co, Cu, and Fe) were prepared by the solgel method at low calcination temperature of 300°C. The properties of the cata...
While it is well established that organics compose a large fraction of the atmospheric aerosol mass, the mechanisms through which organics are incorporated into atmospheric aerosols are not well understood. Acid-catalyzed reactions of compounds with carbonyl groups have recently been suggested as important pathways for transfer of volatile organics into acidic aerosols. In the present study, we...
The use of molecularly imprinted polymers in synthetic organic chemistry is reviewed. These materials are prepared in the presence of a template for which they carry a functional and stereochemical “memory” and can be likened to artificial antibodies or enzymes. Their unique properties have been exploited by the use of imprinted polymers as stereoand regio-selective solid supports in condensati...
In this study, immobilized CuAlO2 onto the ZSM-12&35 composite was prepared and used as a photocatalyst to remove N-containing oil pollutants (Carbazole) through advanced oxidation. In this method, acetone is used as a reaction solvent that can be partially converted to fuel oxygenates compounds (Octane enhancers) through an aldol condensation reaction. Photocatalyst characterization was perfor...
Acetaldehyde reacts with hemoglobin in vitro to produce acetaldehyde-hemoglobin adducts, but we could not detect these in the blood of 20 alcoholics, either by cation-exchange chromatography or agar gel electrophoresis. Thus, contrary to previous reports, this test is not a reliable marker of alcohol abuse. Nuclear magnetic resonance and gas chromatographic-mass spectroscopic analysis of acetal...
Lewis acidic zeolites are used to synthesize unsaturated dicarboxylic acid esters via aldol condensation of keto esters. Hafnium-containing BEA (Hf-BEA) zeolites catalyze the condensation of ethyl pyruvate into diethyl 2methyl-4-oxopent-2-enedioate and diethyl 2-methylene-4oxopentanedioate (an itaconic acid ester analogue) with a selectivity of ca. 80% at ca. 60% conversion in a packed-bed reac...
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