نتایج جستجو برای: aldol condensation reaction

تعداد نتایج: 441341  

Journal: :Clinical chemistry 1984
F R Homaidan L J Kricka P M Clark S R Jones T P Whitehead

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...

Journal: :The Journal of organic chemistry 2009
Dirk Menche Jorma Hassfeld Jun Li Kerstin Mayer Sven Rudolph

A modular total synthesis of the potent V-ATPase inhibitors archazolid A and B is reported. The convergent preparation was accomplished by late-stage diversification of joint intermediates. Key synthetic steps involve asymmetric boron-mediated aldol reactions, two consecutive Still-Gennari olefinations to set the characteristic (Z,Z)-diene system, a Brown crotyboration, and a diastereoselective...

2005
G. FRANCIS R. JOHN AND J. THOMAS

1. Elastins purified by various methods from the ligamentum nuchae and the lungs of cattle of various ages were analysed for amino acid compositions and lysine-derived cross-links. 2. In fully mature elastins from adults the main cross-links were desmosine, isodesmosine and lysinonorleucine and the so-called aldol-condensation product. Trace amounts of merodesmosine were also found. 3. During t...

Journal: :Biomedicine and chemical sciences 2022

Nine copolyesters were prepared from a dicarboxylic acid, curcumin analogues (monocarbonyl) and phenophthalene dye in the mole ratio of 2:1:1 by direct polycondensation using triethylamine (Et3N) as condensation agent. The used is 2,6-Pyridine dicarbonyl dichloride acid. acid catalyzed Aldol reaction. These characterized FT-IR. fluorescence synthesized was also investigated. Furthermore, Thermo...

Journal: :Green Chemistry 2021

The strategy for converting glucose directly to new types of furanic compounds under mild conditions is based on retro-aldol condensation followed by aldol C2 and C4 fragments with acetylacetone.

A new and efficient method has been developed for the synthesis of 4-aryl-7-benzylidene-1,3,4,5,6,7-hexahydro-2H-cyclopenta[d]pyrimidin-2-ones through Biginelli-like reaction of cyclopentanone, with urea/thiourea and aromatic aldehyde employing p-dodecylbenzenesulfonic acid (DBSA) as a recyclable catalyst under solvent-free condition. The recovered catalyst was recycled for further runs. The pr...

2014
Guan-Hua Ma Bo Jiang Xing-Jun Tu Yi Ning Shu-Jiang Tu Guigen Li

An efficient combination between the Passerini three-component reaction and aldol condensation has been developed for the synthesis of bicyclic isocoumarins with different substituted patterns via solvent-dependent domino pathways. These two operationally friendly methods simultaneously install C-O and C-C bonds in a one-pot manner, allowing the utilization of low-cost and readily accessible 2-...

2007
P. L. Majumder Suman Majumder

The mechanism of formation of coumarin (1) by Perkin reaction from salicylaldehyde was shown to involve exclusively a basecatalyzed intramolecular aldol-type condensation of O-acetyl salicylaldehyde (2) as an obligatory intermediate followed by dehydration. Direct evidence in support of this contention was provided by the formation of coumarin and 3-phenyl coumarin(5) as the sole products in th...

Journal: :Química hoy chemistry sciences 2023

The monomer 3-hexylthiophen-2,5-dicarboxaldehyde was synthetized from precursor 3-hexylthiophene by VilsmeierHaack reaction. Three p-type semiconductor polymers (PHT-P, PHT-B and PHT-H) were aldol condensation this with three different ketones (propanone, butanone hexanone). composites created adding PbS/ZnS nanoparticles to these polymers. Light absorption increased the red composites. Electri...

Journal: :Silicon 2021

In the present study, a hollow MgO/SiO2 nanocatalyst with high alkaline properties was prepared. This heterogeneous catalyst prepared in several steps to create great active area and decrease density of catalyst. The framework applied for reaction cyclohexanone, malononitrile benzaldehyde synthesis 1 H-isocromene therough Michael addition aldol condensation at room temperature. this method, all...

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