نتایج جستجو برای: imidazoles multicomponent nmr

تعداد نتایج: 72088  

Journal: :Chemical science 2017
Jevgenijs Tjutrins Bruce A Arndtsen

We describe here a tandem catalytic route to prepare imidazoles in a single operation from aryl iodides, imines and CO. The reaction involves a catalytic carbonylation of aryl halides with imines to form 1,3-dipoles, which undergo spontaneous 1,3-dipolar cycloaddition. Overall, this offers an alternative to coupling reactions to construct the (hetero)aryl-imidazole motif, where variation of the...

2017
Jevgenijs Tjutrins Bruce A. Arndtsen

We describe here a tandem catalytic route to prepare imidazoles in a single operation from aryl iodides, imines and CO. The reaction involves a catalytic carbonylation of aryl halides with imines to form 1,3dipoles, which undergo spontaneous 1,3-dipolar cycloaddition. Overall, this offers an alternative to coupling reactions to construct the (hetero)aryl-imidazole motif, where variation of the ...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2006
Jun Hu Riqiang Fu Katsuyuki Nishimura Li Zhang Huan-Xiang Zhou David D Busath Viksita Vijayvergiya Timothy A Cross

The heart of the H+ conductance mechanism in the homotetrameric M2 H+ channel from influenza A is a set of four histidine side chains. Here, we show that protonation of the third of these imidazoles coincides with acid activation of this transmembrane channel and that, at physiological pH, the channel is closed by two imidazole-imidazolium dimers, each sharing a low-barrier hydrogen bond. This ...

Journal: :ACS applied polymer materials 2022

The development of bio-based epoxy resins from aliphatic biomass and lignin has rapidly increased over the past few decades. While thermal curing such monomers with polyfunctional amines anhydrides been intensively discussed in literature, surprisingly, their polymerization behavior using alcohols as co-curing agents resulting mechanical properties have not investigated detail up to now. Herein...

2012
Momoh-Jimoh E. Salami Ismaila B. Tijani Bin Ismail

Multiexponential transient signals are particularly important due to their occurrences in many natural phenomena and human applications. For instance, it is important in the study of nuclear magnetic resonance (NMR) in medical diagnosis (Cohn-Sfetcu et al., 1975)), relaxation kinetics of cooperative conformational changes in biopolymers (Provencher, 1976), solving system identification problems...

2017
Andreas C Boukis Baptiste Monney Michael A R Meier

The Biginelli reaction was combined with the Passerini reaction for the first time in a sequential multicomponent tandem reaction approach. After evaluation of all possible linker components and a suitable solvent system, highly functionalized dihydropyrimidone-α-acyloxycarboxamide compounds were obtained in good to excellent yields. In a first reaction step, different 3,4-dihydropyrimidin-2(1H...

Journal: :Journal of Molecular Structure 2022

The title compound Ethyl 4-aminobenzoate – 3,5-dinitrosalicylate salt [ES] has been synthesized, crystallized and characterized using FTIR, 1H NMR, 13C NMR confirmed by single crystal X-ray diffraction method. molecular structure packing were carried out theoretical optimization at the DFT level concept of atom in molecules (AIM) analysis was performed. Further, is visualized quantified Hirshfe...

2002
David Gabriel Regan

Molecular diffusion is an inherent feature of all fluid systems. The processes and interactions that characterize these systems are in some way dependent upon the mobility of the component molecules. Pulsed field-gradient spin-echo nuclear magnetic resonance (PGSE NMR) is a powerful tool for the study of molecular diffusion; for heterogeneous systems, such as those typically found in biology, t...

2011
Saman Damavandi

A survey of the pertinent literature reveals that aryl imidazoles have been found to possess a wide spectrum of biological activity such as antibacterial [1], antirheumatoid arthritis [2], antitubercular [3], antiviral [4], anti-inflammatory [5] and anticancer activities [6-8]. Specifically, it has been revealed from the literature that imidazoles fused with indole nucleus possess various biolo...

Journal: :Organic & biomolecular chemistry 2015
Tarun Kumar Deepti Verma Rubem F S Menna-Barreto Wagner O Valença Eufrânio N da Silva Júnior Irishi N N Namboothiri

A one-pot, two step synthesis of highly substituted imidazoles has been carried out in good to excellent yields for the first time via a cascade intermolecular aza-SN2'-intramolecular aza-Michael addition involving a variety of Morita-Baylis-Hillman acetates of nitroalkenes and amidines in the presence of DABCO at room temperature. The synthetic and biological utility of the products has been d...

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