Dehydrogenation of Hantzsch esters: abnormal course of reaction of the 4-p-dimethylaminophenyl derivative

Bacon, R. G. R.; Osuntogun, Bolanle A.

doi:10.1039/c39790001159

Cited by 4 publications

(2 citation statements)

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“…However, 4-alkyl-1,4-dihydropyridines in the presence of nitrous acid lose the alkyl group to give pyridines unsubstituted in the 4-position (167). 125 Similarly, 4-[p-(dimethylamino)phenyl]-l,4-dihydropyridine 168 reacts with electrophiles such as nitrite to give products of electrophilic aromatic substitution 169 and the pyridine.125…”

Section: Photochemical Reactionsmentioning

confidence: 99%

Recent advances in the chemistry of dihydropyridines

Stout¹,

Meyers²

1982

Chem. Rev.

901

266

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Section: Photochemical Reactionsmentioning

confidence: 99%

Recent advances in the chemistry of dihydropyridines

Stout¹,

Meyers²

1982

Chem. Rev.

901

266

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“…Thus, 1,4-dihydropyridines obtained from some aliphatic aldehydes [6-10], polyfluorobenzaldehydes [11], and 4-(dimethylamino)benzaldehyde (1) [12], are aromatized with the splitting off the substituent in the γ-position by the action of certain oxidizing agents, sodium cyanide, and electrophilic reagents.…”

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confidence: 99%

Aromatization with dearylation on Hantzsch cyclocondensation of 4-(dimethylamino)benzaldehyde, cyclohexane-1,3-diones, and some 1,3-[N,C]dinucleophiles

Dzvinchuk

Tolmachova

Chernega

et al. 2009

Chem Heterocycl Comp

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The Hantzsch pyridine synthesis, including pyridines condensed with other rings, consists of two stages, the formation of the 1,4-dihydropyridine ring and its subsequent oxidation [1][2][3][4][5]. The method has been improved in practical organic chemistry during 125 years and has been changed in principle when obtaining compounds with a γ-unsubstituted pyridine ring, since the classical scheme using formaldehyde gives unsatisfactory results [6].It was established primarily that formaldehyde may be replaced by other aldehydes. Thus, 1,4-dihydropyridines obtained from some aliphatic aldehydes [6-10], polyfluorobenzaldehydes [11], and 4-(dimethylamino)benzaldehyde (1) [12], are aromatized with the splitting off the substituent in the γ-position by the action of certain oxidizing agents, sodium cyanide, and electrophilic reagents.Secondly, procedures were proposed for conversion of the two-stage synthesis into one stage. For example, 1,4-dihydropyridines obtained from antipyrine-4-carbaldehyde, are aromatized with the splitting off antipyrine even under the conditions of formation (20 o C, 18 h), although the initial aldehyde must first be converted into the more reactive chloropyridinium salt [13]. We have found that the aldehyde 1 mentioned above is more convenient for that purpose. On carrying out the reaction involving it in boiling acetic acid (120 o C, 2 h), as shown in the synthesis of derivatives of acridine [14], pyrazolo[3,4-b]pyridine [15], and

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ChemInform Abstract: DEHYDROGENATION OF HANTZSCH ESTERS: ABNORMAL COURSE OF REACTION OF THE 4‐P‐DIMETHYLAMINOPHENYL DERIVATIVE

Bacon¹,

Osuntogun²

1980

Chemischer Informationsdienst

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Dehydrogenation of Hantzsch esters: abnormal course of reaction of the 4-p-dimethylaminophenyl derivative

Abstract: Reactions of diethyl 4-p-dimethylaminophenyl-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate with various electrophiles, X+, give diethyl 2,6-dimethylpyridine-3,5-dicarboxylate and compounds which include the ips0 substitution products, p-C,H,X.NMe,.

Cited by 4 publications

References 0 publications

Recent advances in the chemistry of dihydropyridines

Recent advances in the chemistry of dihydropyridines

Aromatization with dearylation on Hantzsch cyclocondensation of 4-(dimethylamino)benzaldehyde, cyclohexane-1,3-diones, and some 1,3-[N,C]dinucleophiles

ChemInform Abstract: DEHYDROGENATION OF HANTZSCH ESTERS: ABNORMAL COURSE OF REACTION OF THE 4‐P‐DIMETHYLAMINOPHENYL DERIVATIVE

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