Sterically Crowded Heterocycles. III. A General Approach to Imidazo[1,2-a]pyridines by Ferricyanide Oxidation of Quaternary Pyridinium Salts

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Title:Sterically Crowded Heterocycles. III. A General Approach to Imidazo[1,2-a]pyridines by Ferricyanide Oxidation of Quaternary Pyridinium Salts
Creators:
Kubík, Richard
Böhm, Stanislav
Ruppertová, Iveta
Kuthan, Josef
Journal or Publication Title:
Collection of Czechoslovak Chemical Communications, 61, 1, pp. 126-138
Uncontrolled Keywords:Ferricyanide oxidation, Imidazo[1,2-<i>a</i>]pyridines

Abstract

Substituted 1-(pyridin-2-yl)-2,4,6-triphenylpyridinium perchlorates <strong>1b-1e</strong> were converted with potassium ferricyanide and potassium hydroxide to sterically crowded 2-phenyl-3-[(<i>Z</i>)-1,3-diphenyl-3-oxopropenyl]imidazo[1,2-<i>a</i>]pyridines <strong>2b-2e</strong> accompanied by minor isomeric 2-benzoyl-3,5-diphenyl-1-(pyridin-2-yl)pyrroles <strong>3c</strong>-<strong>3e</strong>. 4-Phenyl-2,6-di(4-substituted phenyl)-1-(pyridin-2-yl)pyridinium salts <strong>4a</strong>, <strong>4b</strong> gave exclusively corresponding imidazo[1,2-<i>a</i>]pyridines <strong>5a</strong>, <strong>5b</strong> while the ferricyanide oxidation of 1-(5-iodo- and 5-cyanopyridin-2-yl)-2,4,6-triphenylpyridinium perchlorates <strong>6a</strong>, <strong>6b</strong> led to mixtures of major imidazo[1,2-<i>a</i>]pyridines <strong>7a-7c</strong> and minor pyrroles <strong>8a-8c</strong>. Some mechanistic aspects of the oxidation procedure are discussed in connection with a resistance of 2,6-diphenyl-1,3,5-trimethylpyridinium perchlorate (<strong>9c</strong>) towards the oxidizing agents.

Title:Sterically Crowded Heterocycles. III. A General Approach to Imidazo[1,2-a]pyridines by Ferricyanide Oxidation of Quaternary Pyridinium Salts
Creators:
Kubík, Richard
Böhm, Stanislav
Ruppertová, Iveta
Kuthan, Josef
Uncontrolled Keywords:Ferricyanide oxidation, Imidazo[1,2-<i>a</i>]pyridines
Divisions:Life and Chemical Sciences > Institute of Organic Chemistry and Biochemistry > Collection of Czechoslovak Chemical Communications
Journal or Publication Title:Collection of Czechoslovak Chemical Communications
Volume:61
Number:1
Page Range:pp. 126-138
ISSN:0010-0765
E-ISSN:1212-6950
Publisher:Institute of Organic Chemistry and Biochemistry
Related URLs:
URLURL Type
http://dx.doi.org/10.1135/cccc19960126UNSPECIFIED
ID Code:920
Item Type:Article
Deposited On:06 Feb 2009 17:05
Last Modified:06 Feb 2009 16:05

Citation

Kubík, Richard; Böhm, Stanislav; Ruppertová, Iveta; Kuthan, Josef (1996) Sterically Crowded Heterocycles. III. A General Approach to Imidazo[1,2-a]pyridines by Ferricyanide Oxidation of Quaternary Pyridinium Salts. Collection of Czechoslovak Chemical Communications, 61 (1). pp. 126-138. ISSN 0010-0765

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