Dication ethers—10. Stable dipoles from a bis-acridinium ether salt and cyclic ß-diketonates

Maas, Gerhard; Weber, H.-M.

doi:10.1016/s0040-4020(01)82347-4

Cited by 3 publications

(1 citation statement)

References 16 publications

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“…However, competition between C-, O-, and N-alkylation has to be considered when BA anions undergo reactions with electrophiles (Scheme ). For example, products arising from C-attack were obtained in reactions with carbonyl compounds. , Alkylations with dication ethers, , alkyl iodides, dimethyl sulfate, or diazomethane yield mixtures of C-, O-, and N-alkylated products of BA. N-alkylated products are solely formed by reactions of 5,5-dialkyl-substituted BA with triphenylmethylium ions. , …”

Section: Introductionmentioning

confidence: 99%

Kinetics of Electrophilic Alkylations of Barbiturate and Thiobarbiturate Anions

Schade¹,

Tchernook²,

Bauer³

et al. 2017

J. Org. Chem.

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Second-order rate constants (k) of the reactions of various barbiturate anions such as the parent barbiturate, 1,3-dimethylbarbiturate, 2-thiobarbiturate, and 1,3-diethyl-2-thiobarbiturate with diarylcarbenium ions and Michael acceptors have been determined in dimethyl sulfoxide solution at 20 °C. The reactivity parameters N and s of the barbiturate anions were derived from the linear plots of log k versus the electrophilicity parameters E of these reference electrophiles, according to the linear-free-energy relationship log k (20 °C) = s (E + N). Several reactions of these nucleophiles with benzylidenemalononitriles and quinone methides proceeded with reversible formation of the new C-C-bond followed by rate-determining proton shift. No evidence for initial attack of the electrophiles at the enolate oxygens of these nucleophiles was found by the kinetic measurements, in line with quantum chemical DFT calculations, which showed that in all cases C-attack is kinetically and thermodynamically preferred over O-attack. The nucleophilic reactivities of barbiturate anions were compared with those of structurally related carbanions, e.g., Meldrum's acid and dimedone anions.

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Section: Introductionmentioning

confidence: 99%

Kinetics of Electrophilic Alkylations of Barbiturate and Thiobarbiturate Anions

Schade¹,

Tchernook²,

Bauer³

et al. 2017

J. Org. Chem.

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Dikationether, 11. Ambidoselektive Reaktionen von β‐Ketoenolaten mit Dikationethern

1986

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Die elektrophile Übertragung einer Tetramethylformamidinum‐Gruppe aus dem Bis‐(N,N,N′,N′‐tetramethylformamidinio)ether‐Salz 5a auf die ambidenten β‐Ketoenolate 7a–h, j und das β‐Ketonitril‐Anion 7i erfolgt in Acetonitril ausschileßlich am Enolatsauerstoff, wobei man die Uronium‐Salze 8a–j erhält. Aus den acyclischen β‐Ketoenolaten 7a – f entstehen diastereoselektiv die β‐Acylenolether‐Salze (E)‐8a–f. Das Diimidazolinioether‐Salz 5b und die Dipyridinioether‐Salze 5c, d reagieren mit dem Anion von Dimedon ebenfalls ausschließlich am Sauerstoff (8k, 15, 18). Aus 5c und dem Anion von Meldrumsäure erhält man unter C/C‐Verknüpfung das Olefin 16. – Eine Röntgenstrukturanalyse von (E)‐8f wurde ausgeführt.

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Dehydroacetic Acid, Triacetic Acid Lactone, and Related Pyrones

Moreno‐Mañas

Pleixats

1992

Advances in Heterocyclic Chemistry

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Dication ethers—10. Stable dipoles from a bis-acridinium ether salt and cyclic ß-diketonates

Cited by 3 publications

References 16 publications

Kinetics of Electrophilic Alkylations of Barbiturate and Thiobarbiturate Anions

Kinetics of Electrophilic Alkylations of Barbiturate and Thiobarbiturate Anions

Dikationether, 11. Ambidoselektive Reaktionen von β‐Ketoenolaten mit Dikationethern

Dehydroacetic Acid, Triacetic Acid Lactone, and Related Pyrones

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