نتایج جستجو برای: imidazoles multicomponent nmr

تعداد نتایج: 72088  

2015
Yan-Li Cui Xiao-Ning Guo Ying-Yong Wang Xiang-Yun Guo

N-aryl imidazoles play an important role as structural and functional units in many natural products and biologically active compounds. Herein, we report a photocatalytic route for the C-N cross-coupling reactions over a Cu/graphene catalyst, which can effectively catalyze N-arylation of imidazole and phenylboronic acid, and achieve a turnover frequency of 25.4 h(-1) at 25°C and the irradiation...

Journal: :Molecules 2009
Yuka Kawashita Masahiko Hayashi

A variety of heteroaromatic compounds, such as substituted pyridines, pyrazoles, indoles, 2-substituted imidazoles, 2-substituted imidazoles, 2-arylbenzazoles and pyrimidin-2(1H)-ones are synthesized by oxidative aromatization using the activated carbon and molecular oxygen system. Mechanistic study focused on the role of activated carbon in the synthesis of 2-arylbenzazoles is also discussed. ...

Journal: :Journal of the American Chemical Society 2005
David A Evans Keith R Fandrick Hyun-Ji Song

An enantioselective Friedel-Crafts alkylation with alpha,beta-unsaturated 2-acyl imidazoles and electron-rich aromatic nucleophiles catalyzed by bis(oxazolinyl)pyridine-scandium(III) triflate complexes has been accomplished. These alpha,beta-unsaturated 2-acyl imidazoles are effective electrophiles for the Friedel-Crafts reaction. The resulting adduct 2-acyl imidazole is easily converted to ami...

2003
Varoujan A. Yaylayan Luke J.W. Haffenden

Studies with C-2-labelled glycine and alanine in model systems containing 2,3-butanedione, glyceraldehyde or glyoxal have indicated that imidazoles and oxazoles can be formed from a-dicarbonyl compounds through Strecker reaction and subsequent formation of a-amino carbonyl reactive intermediates. These intermediates can react with any aldehyde in the reaction mixture to form an imine which in t...

Journal: :Molbank 2022

We elaborated a convenient one-step approach for the synthesis of previously unknown 2-(5-acetyl-7-methoxy-2-(4-methoxyphenyl)benzofuran-3-yl)acetic acid. The suggested protocol includes multicomponent reaction acetovanillone, 4-methoxyphenylglyoxal and Meldrum’s have demonstrated that considered is one-pot telescoped process including preliminary condensation components in MeCN followed by aci...

1999
Takahiro Ueda Shigenori Nagatomo Hirotsugu Masui Nobuo Nakamura Shigenobu Hayashi

Intermolecular hydrogen bonds of the type N–H...N in crystals of imidazole and its 4-substituted and 4,5-disubstituted derivatives were studied by N CP/MAS NMR and an ab initio molecular orbital (MO) calculation. In the N CP/MAS NMR spectrum of each of the imidazole derivatives, two peaks due to the two different functional groups, >NH and =N-, were observed. The value of the N isotropic chemic...

Journal: :Chemistry 2009
Mikhail Y Berezin Jeff Kao Samuel Achilefu

An imidazole moiety is often found as an integral part of fluorophores in a variety of fluorescent proteins and many such proteins display pH-dependent light emission. In contrast, synthetic fluorescent compounds with incorporated imidazoles are rare and have not been studied as pH probes. In this report, the richness of imidazole optical properties, including pH sensitivity, was demonstrated b...

2011
Baskar Lakshmanan Papiya Mitra Mazumder D. Sasmal Simon Santosh Jena

Anthelmintic resistance creates a major hitch over the decades throughout the world. As per WHO only few drugs are frequently used in the treatment of helminth infestations in human beings. In view of this, an attempt has been made to study the anthelmintic activity of some newly synthesized 1-substituted imidazoles (1a-1d, 2a-2d) were synthesized and characterized by their spectral data. All t...

Journal: :Organic & biomolecular chemistry 2010
Mahiuddin Baidya Frank Brotzel Herbert Mayr

The kinetics of the reactions of some imidazoles, benzimidazoles and benzotriazoles with benzhydrylium ions (diarylcarbenium ions) have been studied photometrically in DMSO, acetonitrile, and aqueous solution at 20 degrees C. The resulting second-order rate constants have been used to determine the nucleophile-specific parameters N and s of these azoles according to the linear-free-energy relat...

Journal: :Journal of Synthetic Organic Chemistry, Japan 1998

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