نتایج جستجو برای: aldehydes

تعداد نتایج: 7935  

Hossein Eshghi Zinat Gordi,

A facile and efficient method for the preparation of 1,1-diacetates of aldehydes is improved. The acidified kaolin with sulfuric acid (2 % w/w) catalyzed 1,1-diacetates formation from aldehydes in solvent-free conditions. Both aromatic and aliphatic aldehydes gave high yields (85-95 %) of the corresponding 1, 1-diacetates. Advantages of this method are the use of inexpensive and selective catal...

Journal: :Angewandte Chemie 2013
Junming Mo Liang Shen Yonggui Robin Chi

Saturated carbonyl compounds, such as aldehydes and esters, are basic building blocks for the synthesis of organic molecules and materials. Reactions with carbonyl compounds as substrates primarily occur at the carbonyl carbon atom (as an electrophilic center) or the a-carbon atom (as a prenucleophile). In organocatalysis, several powerful approaches have been developed for the asymmetric funct...

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 1996
bahman tamami moredin goudarzian

the difficult to handle and store zinc borohydride, zn(bh4)2, is stabilized by supporting it on polyvinylpyridine. this new mild, efficient, selective, and regenerable polymer supported borohydride reducing agent reduces a variety organic compounds such as, aldehydes, a-b-unsaturated carbonyl compounds, acid chlorides, epoxides, disulfides, as well as reductive acetylation of carbonyl compounds...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه گیلان - دانشکده علوم پایه 1388

چکیده ندارد.

Journal: :journal of the iranian chemical research 0
digambar d. gaikwad department of chemistry, govt.college of arts & sciences, aurangabad-4310001, india rajendra p. pawar department of chemistry, deogiri college, aurangabad- 431005, india

a simple extremely fast and efficient approach for the synthesis of substituted indazole ingood to excellent yield catalyzed by using silica sulfuric acid (ssa) in dmso solvent at roomtemperature. this is solid state reaction have been attracting the synthetic organic chemist asthey provided enhance reaction rates, less environmental pollution, greater selectivity, cleanerproducts and manipulat...

Journal: :The British journal of nutrition 1984
R C Siddons C Arricastres D L Gale D E Beever

The primary growth of lucerne (Medicago sativa) was ensiled after treatment with either formic acid alone (4.1 litres/t; silage F) or with formic acid and either formaldehyde (30.5 g/kg crude protein (nitrogen X 6.25; CP); silage FF), glutaraldehyde (44.2 g/kg CP; silage FG) or a mixture of the two aldehydes at approximately half their individual application rates (silage FFG). Compared with fo...

Journal: :Chemical science 2015
Hélio Faustino Iván Varela José L Mascareñas Fernando López

Allenamides participate as two-carbon components in an intermolecular [2 + 2 + 2] cycloaddition with alkenes and aldehydes when treated with catalytic amounts of a phosphite gold complex. The reaction is highly regio- and chemoselective, and works with different types of alkenes, including styrenes, enol ethers or enamides, as well as with aromatic and aliphatic aldehydes. Accordingly, differen...

Journal: :Science 2013
Michael T Pirnot Danica A Rankic David B C Martin David W C MacMillan

The direct β-activation of saturated aldehydes and ketones has long been an elusive transformation. We found that photoredox catalysis in combination with organocatalysis can lead to the transient generation of 5π-electron β-enaminyl radicals from ketones and aldehydes that rapidly couple with cyano-substituted aryl rings at the carbonyl β-position. This mode of activation is suitable for a bro...

Journal: :Applied and environmental microbiology 2000
R W Eaton

The hydratase-aldolase-catalyzed conversion of trans-o-hydroxybenzylidenepyruvate to salicylaldehyde and pyruvate is an intermediate reaction in the conversion of naphthalene to salicylate by bacteria. Here, a variety of aromatic aldehydes and some nonaromatic aldehydes together with pyruvate have been shown to be substrates for aldol condensations catalyzed by this enzyme in extracts of the re...

Journal: :Journal of the American Chemical Society 2010
Nathan T Jui Esther C Y Lee David W C MacMillan

A highly selective, radical-mediated (4 + 2) coupling reaction of aldehydes and conjugated olefins has been achieved through asymmetric SOMO-catalysis. A radical-polar crossover mechanism is proposed wherein olefin addition to a transient enamine radical cation and oxidation of the resulting radical furnishes a cation which is vulnerable to nucleophilic addition. A range of aromatic aldehydes a...

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