نتایج جستجو برای: heterocycles

تعداد نتایج: 2986  

Journal: :Journal of the American Chemical Society 2010
Kevin L Miller Bryan N Williams Diego Benitez Colin T Carver Kevin R Ogilby Ekaterina Tkatchouk William A Goddard Paula L Diaconescu

Group 3 (Sc, Y, Lu, La) benzyl complexes supported by a ferrocene diamide ligand are reactive toward aromatic N-heterocycles by mediating their coupling and, in a few cases, the cleavage of their C-N bonds. When these complexes reacted with 2,2'-bipyridine or isoquinoline, they facilitated the alkyl migration of the benzyl ligand onto the pyridine ring, a process accompanied by the dearomatizat...

Journal: :Chemistry & biology 1999
R Sinha Roy N L Kelleher J C Milne C T Walsh

BACKGROUND The Escherichia coli peptide antibiotic microcin B17 (MccB17) contains four oxazole and four thiazole rings, and inhibits DNA gyrase. The role of individual and tandem pairs of heterocycles in bioactivity has not been determined previously. RESULTS The two tandem 4,2-bisheterocycles in MccB17 were varied by expression of MccB17 or mutants containing altered sequences at Gly39-Ser40...

2014
Roland G. Huber Michael A. Margreiter Julian E. Fuchs Susanne von Grafenstein Christofer S. Tautermann Klaus R. Liedl Thomas Fox

In this study we investigate π-stacking interactions of a variety of aromatic heterocycles with benzene using dispersion corrected density functional theory. We calculate extensive potential energy surfaces for parallel-displaced interaction geometries. We find that dispersion contributes significantly to the interaction energy and is complemented by a varying degree of electrostatic interactio...

2017
Pankaj Jain Pritha Verma Guoqin Xia Jin-Quan Yu

Saturated aza-heterocycles are highly privileged building blocks that are commonly encountered in bioactive compounds and approved therapeutic agents. These N-heterocycles are also incorporated as chiral auxiliaries and ligands in asymmetric synthesis. As such, the development of methods to functionalize the α-methylene C-H bonds of these systems enantioselectively is of great importance, espec...

2014
Hao Yu Hongzhi Tang Ping Xu

Value-added intermediates produced by microorganisms during the catabolism of N-heterocycles are potential building blocks for agrochemical synthesis and pharmaceutical production. 6-Hydroxy-3-succinoyl-pyridine (HSP), an intermediate in nicotine degradation, is an important precursor for the synthesis of drugs and compounds with biological activities. In the present study, we show that an engi...

2014

Commercial preparation of furan proceeds by way of the aldehyde, furfural, which in turn is generated from pentose containing raw materials like corncobs, as shown in the uppermost equation below. Similar preparations of pyrrole and thiophene are depicted in the second row equations. Equation 1 in the third row illustrates a general preparation of substituted furans, pyrroles and thiophenes fro...

Journal: :Organic & biomolecular chemistry 2017
Sofia Kiriakidi Olalla Nieto Faza Antonios Kolocouris Carlos Silva López

The formation of chiral heterocycles via cycloisomerization reactions of allene derivatives has gained relevance due to their associated efficiency and atom-economy. The only drawback that keeps these reactions away from being routine synthetic strategies is the control in the regioselectivity (most often 5-endo vs. 6-endo). In this work, we computationally explore the experimental chemistry re...

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