Pyridinium‐betaine aus Glutacondialdehyd‐Derivaten

Beyer, Hans; Leverenz, Klaus; Schilling, H.

doi:10.1002/ange.19610730804

Cited by 9 publications

(4 citation statements)

References 3 publications

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“…(6). Various directions [10][11][12] were condensed into the following procedure. 76.8 g (0.710 mol) of phenylhydrazine and 72.9 g (0.720 mol) of triethylamine in 200 mL of ethanol were slowly introduced into the stirred and cooled solution of 200 g (0.710 mol) of N-(2,4-dinitrophenyl)pyridinium chloride [10] in 2.0 L of ethanol.…”

Section: Methodsmentioning

confidence: 99%

“…The synthesis of N-arylaminopyridinium salts, based on the Zincke reaction of N- (2,4-dinitrophenyl)-pyridinium chloride with arylhydrazines, has been described in several variants [10][11][12]. We used the cyclization of the intermediate hydrazones by refluxing in glacial acetic acid, as recommended by Beyer and Thieme [12].…”

Section: Preparation Of Pyridinium N-arylimidesmentioning

confidence: 99%

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1,3-cycloadditions of pyridinium N-arylimides

Huisgen

Temme

1999

Heteroatom Chem.

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The title compounds (5a: Ar = C6H5, 5b: Ar = 2‐pyridyl) are 1,3‐dipoles of the azomethine imine type; their 1,3‐cycloadditions are accompanied by the loss of the pyridinium resonance energy. As a consequence, the interaction with electron‐deficient ethylenes gives rise to cycloaddition/cycloreversion equilibria, in contrast to the cycloadditions of isoquinolinium N‐arylimides; enamines do not react with 5. The cycloadducts of 5a to dimethyl maleate, fumaronitrile, and acrylonitrile are Nβ‐dienyl‐phenylhydrazines, which undergo a hydrazo rearrangement affording aminals derived from a tetracyclic system. Like enamines, the dienehydrazine system of the cycloadducts reacts with dimethyl acetylenedicarboxylate by [2 + 2] cycloaddition and electrocyclic ring opening furnishing tetrahydropyrrolo[3,2‐a]azocine derivatives. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 79–88, 1999

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Section: Methodsmentioning

confidence: 99%

Section: Preparation Of Pyridinium N-arylimidesmentioning

confidence: 99%

1,3-cycloadditions of pyridinium N-arylimides

Huisgen

Temme

1999

Heteroatom Chem.

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“…To solve the first problem, N-substituted pyridinium imides (3-6, Fig. 1) were introduced, where the exocyclic nitrogen was equipped with electron-withdrawing groups such as acyl (3), 11 alkoxycarbonyl (4), 12 aryl (5), 13 and even nitro groups (6). 14 Such modification indeed brought the desired stability of the starting material, but the process B now may involve an additional step (such as hydrolysis of the alkoxycarbonyl or acyl groups) and becomes even more problematic.…”

Section: Introductionmentioning

confidence: 99%

“…of 10a was employed. f The two regioisomers can be distinguished by13 C NMR spectroscopy. See ref.21.…”

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confidence: 99%

Aryne [3 + 2] cycloaddition with N-sulfonylpyridinium imides and in situ generated N-sulfonylisoquinolinium imides: a potential route to pyrido[1,2-b]indazoles and indazolo[3,2-a]isoquinolines

Zhao

et al. 2012

Org. Biomol. Chem.

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The aryne [3 + 2] cycloaddition process with pyridinium imides breaks the aromaticity of the pyridine ring. By equipping the imide nitrogen with a sulfonyl group, the intermediate readily eliminates a sulfinate anion to restore the aromaticity, leading to the formation of pyrido[1,2-b]indazoles. The scope and limitation of this reaction are discussed. As an extension of this chemistry, N-tosylisoquinolinium imides, generated in situ from N'-(2-alkynylbenzylidene)-tosylhydrazides via an AgOTf-catalyzed 6-endo-dig electrophilic cyclization, readily undergo aryne [3 + 2] cycloaddition to afford indazolo[3,2-a]-isoquinolines in the same pot, offering a highly efficient route to these potential anticancer agents.

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