Results 191 to 200 of about 30,087 (242)

Syntheses Using Pyridinium Salts

Angewandte Chemie International Edition in English, 1963
AbstractThis review discusses syntheses leading to a new type of N‐vinylpyridinium salts, to novel anionocyanines, to aminophenazines and alloxazines, as well as to (aza‐) dehydroquinolizinium, acridizinium, and morphanthridizinium salts. In addition, Mannich reactions and aminoalkylations at active methylene groups of cycloimmonium salts, and their ...
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Imidazo [1,2‐a] pyridinium salts

Journal of Heterocyclic Chemistry, 1965
Abstract2‐Alkylamino‐ or arylaminopyridines react directly with α‐bromoketones to afford 1‐alkyl‐ or 1‐arylimidazo[1,2‐a]pyridinium salts with substituents at position 2. Use of chloroacetaldoxime as the quaternizing agent yields (after hydrolysis) the imidazo‐[1,2‐a]pyridinium ion with no substituent at position 2.
C. K. Bradsher, E. F. Litzinger, M. F. Zinn   +2 more
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Oxidation of polysubstituted pyridinium salts

Collection of Czechoslovak Chemical Communications, 1982
Oxidation of 1-substituted 2,4,6-triphenylpyridinium salts Ia-Ij with potassium ferricyanide in an alkaline medium was accompanied by contraction of the pyridine ring and formation of 1,2,3,5-tetrasubstituted pyrroles II. The derivative IIf underwent facile electrophilic substitution in the position 4. Contrary to compounds Ia-Ij, the 1-substituted-2,6-
Petr Nesvadba, Josef Kuthan
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Investigation of Methyl Pyridinium-2-aldoxime Salts

Journal of Pharmaceutical Sciences, 1961
Methyl pyridinium-2-aldoxime iodide (2-PAM iodide) has been reported to be effective in preventing and overcoming the toxic effects in animals poisoned with organic phosphorus compounds that are inhibitors of the cholinesterase enzymes. In order to obtain greater water solubility of the oxime and to eliminate undesirable side effects due to the iodide ...
A A, KONDRITZER, R I, ELLIN, L J, EDBERG
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Infrared spectra of pyridinium salts in solution—III. Associations of pyridinium salts with bases

Spectrochimica Acta Part A: Molecular Spectroscopy, 1983
Associations of pyridinium salts X-Py+HA− (A− = SbCl−6, ClO−4, BF−4, I−, Br− and Cl−) with a wide series of aprotic bases and with protic solvents (water and fluoroalcohols) have been studied by infrared spectroscopic methods. Constants of association Ka of the pyridinium salts with the bases at different temperatures have been measured and enthalpy ...
S.E. Odinokov, A.A. Mashkovsky, A.A. Nabiullin   +2 more
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Pyridinium Salts as Organophosphate Antagonists

2015
By a standard screening in vivo, a series of pyridinium salts were tested for their protective activity against organophosphate poisoning. In order to obtain information about the protective mechanisms, several biochemical properties of these compounds were investigated in vitro, viz., their influence upon the enzymes cholineacetyltransferase and ...
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Thiazolo [3,2‐a] pyridinium salts

Journal of Heterocyclic Chemistry, 1966
AbstractThe sulfides formed by the reaction of α‐halo ketones or α‐halo acetals with 2‐mercaptopyridine may be cyclized in good yield to form thiazolo[3, 2‐a]pyridinium salts. The presence of chloro or nitro substituents on the pyridine ring does not interfere with the synthesis.
C. K. Bradsher, D. F. Lohr
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Thiazolopyridinium salts. Part II. Approaches to thiazolo[3,4-a]-pyridinium salts and isothiazolo[2,3-a]pyridinium salts

Journal of the Chemical Society C: Organic, 1969
Attempts to synthesise thiazolo[3,4-a]pyridinium salts (3) and isothiazolo[2,3-a]pyridinium salts (2) by dehydration with boiling acetic anhydride of the 5,6,7,8-tetrahydro-8-oxothiazolo[3,4-a]pyridinium salts (11) and (12) and of the 4,5,6,7-tetrahydro-4-oxoisothiazolo[2,3-a]pyridinium salt (6) respectively are reported. The reasons for the failure of
D. G. Jones, Gurnos Jones
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The synthetic potential of pyridinium salt photochemistry

Photochemical & Photobiological Sciences, 2008
The discovery in the 1970s by Kaplan, Wilzbach and Pavlik that pyridinium salts undergo a unique cyclization reaction to produce bicyclic-aziridines was virtually unrecognized for nearly three decades. It was only comparatively recently that the process was explored in more detail and its synthetic potential exploited.
Jiwen, Zou, Patrick S, Mariano
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Iridium‐Catalyzed Asymmetric Hydrogenation of Pyridinium Salts

Angewandte Chemie International Edition, 2012
As one of the most straightforward and powerful approaches for the preparation of optically active compounds, asymmetric hydrogenation has been successfully used for different types of aromatic compounds, including quinolines, isoquinolines, quinoxalines, indoles, pyrroles, furans, imidazoles, and aromatic carbocyclic ring, with excellent ...
Zhi-Shi, Ye, Mu-Wang, Chen, Qing-An, Chen, Lei, Shi, Ying, Duan, Yong-Gui, Zhou   +5 more
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