نتایج جستجو برای: substituted pyridines

تعداد نتایج: 45278  

Journal: :Chemical communications 2008
Herbert Waldmann Marc Kühn Wei Liu Kamal Kumar

An efficient reagent-controlled methodology for generating highly substituted diverse scaffolds from a common substrate has been developed; thus, treatment of a common precursor with different desilylating reagents, such as ammonium fluoride, caesium fluoride and PPTS, triggers different domino reaction sequences, yielding highly substituted pyridines, phenols and benzopyrans, respectively; the...

Journal: :Chemical communications 2014
Vincent Richard Mélinda Ipouck Delphine S Mérel Sylvain Gaillard Richard J Whitby Bernhard Witulski Jean-Luc Renaud

We report a new, simple and air-stable iron(II) complex pre-catalyst for the synthesis of substituted pyridines via a [2+2+2] cycloaddition between diynes and nitrile derivatives.

2004
A. Klapars E. Vedejs

Electrophilic aromatic substitution reactions of pyridines are extraordinarily challenging. Instead of C-substitution at the pyridine ring, the electrophile typically forms an adduct with the pyridine nitrogen, which even further deactivates the already electron deficient pyridine ring toward electrophilic substitution. For example, the direct nitration of pyridine may require a reaction temper...

2009
Reinhold Zimmer Elmar Schmidt Michal Andrä Marcel-Antoine Duhs Igor Linder Hans-Ulrich Reissig

A number of 4-aryl- and 4-alkynyl-substituted 6H-1,2-oxazines 8 and 9 have been prepared in good yields via cross coupling reactions of halogenated precursors 2, which in turn are easily accessible by bromination of 6H-1,2-oxazines 1. Lewis-acid promoted reaction of 1,2-oxazine 9c with 1-hexyne provided alkynyl-substituted pyridine derivative 12 thus demonstrating the potential of this approach...

Journal: :Bioorganic & medicinal chemistry letters 2003
Istvan J Enyedy Sukumar Sakamuri Wahiduz A Zaman Kenneth M Johnson Shaomeng Wang

Abnormal dopamine signaling in brain has been implicated in several conditions such as cocaine abuse, Parkinson's disease and depression. Potent and selective dopamine transporter inhibitors may be useful as pharmacological tools and therapeutic agents. Simple substituted pyridines were discovered as novel dopamine transporter (DAT) inhibitors through pharmacophore-based 3D-database search. The...

Journal: :ACS Medicinal Chemistry Letters 2012

2014
Sylvestre P J T Bachollet Jérôme F Vivat Dean C Cocker Harry Adams Joseph P A Harrity

The aza-Diels-Alder cycloaddition of 1,2,4-triazines with alkynes offers a rapid and convenient method for the synthesis of highly substituted pyridines, but often requires harsh conditions and long reaction times. The present study offers a solution to these limitations by use of a temporary tether established by a Lewis acid-base complexation of in situ generated alkynylboranes and triazines ...

2013
Maria Eugenia Castro Maria Judith Percino Victor M. Chapela Margarita Ceron Guillermo Soriano-Moro Jorge Lopez-Cruz Francisco J. Melendez

A combined theoretical and experimental study on the structure, infrared, UV-Vis and 1H NMR data of trans-2-(m-cyanostyryl)pyridine, trans-2-[3-methyl-(m-cyanostyryl)]pyridine and trans-4-(m-cyanostyryl)pyridine is presented. The synthesis was carried out with an efficient Knoevenagel condensation using green chemistry conditions. Theoretical geometry optimizations and their IR spectra were ca...

2010
Tilman Lechel Irene Brüdgam Hans-Ulrich Reissig

A series of trifluoromethyl-substituted 3-alkoxypyridinol derivatives has been deprotected to furnish pyridine-3,4-diol derivatives in good yields. The X-ray crystal structure analysis proved that a 1:1 mixture of pyridine-3,4-diols and their pyridin-4-one tautomers exist in the solid state. Subsequent conversion into bis(perfluoroalkanesulfonate)s were smoothly achieved. The obtained compounds...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید