I. Über ringförmige Arsenverbindungen der aromatischen Reihe

Wieland, Heinrich; Rheinheimer, W.

doi:10.1002/jlac.19214230102

Cited by 35 publications

(13 citation statements)

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“…. (6) the mechanism for this step of the reaction. From Eqn 6, a mean value of k = 0.842 1 mole-ls-l was obtained.…”

Section: Resultsmentioning

confidence: 99%

The Mechanism of Formation of Phenosafranine Dyes

Corbett

1972

Journal of the Society of Dyers and Colourists

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The formation of phenosafranine dyes, from the oxidation of mixtures of p‐diamines and arylamines, is shown to be a seven‐step process. It entails oxidation of the p‐diamine to the p‐benzoquinonedi‐imine, which, as its conjugate acid, reacts with the arylamine to give a diarninodiphenylamine. Rapid oxidation of this gives an indamine that reacts, as its conjugate acid, with a second molecule of the arylamine to give a tetramino compound that is rapidly oxidised to the corresponding arylaminoindamine. The latter compound, in the form of its conjugate acid, undergoes intramolecular cyclisation, followed by rapid oxidation, to give the phenosafranine. In dilute solution (˜10‐4m), all but the four oxidation steps are slow and proceed at comparable rates, whereas, under preparative conditions, the arylamine addition and the intramolecular cyclisation are the slow steps.

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“…. (6) the mechanism for this step of the reaction. From Eqn 6, a mean value of k = 0.842 1 mole-ls-l was obtained.…”

Section: Resultsmentioning

confidence: 99%

The Mechanism of Formation of Phenosafranine Dyes

Corbett

1972

Journal of the Society of Dyers and Colourists

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“…Zahlreiche arsenorganische Verbindungen wurden synthetisiert und geprüft. Da Arbeiten über diese Substanzklasse im Zeitalter von Salvarsan und anderen arsenhaltigen Arzneimitteln wissenschaftlich von allgemeinerem Interesse waren, publizierte Wieland diese Arbeiten nach Aufhebung der militärischen Geheimhaltungspflicht 1920 und 1923 in Liebigs Annalen 40. Seine Veröffentlichungen zeigen, dass er noch im Krieg das Diphenylaminchlorarsin (“Adamsit”) gefunden hatte, das die Amerikaner dank ihres im “Chemical Warfare Service” tätigen Kampfstoffexperten Roger Adams41 kurz vor Kriegsende ebenfalls synthetisiert hatten, allerdings zu spät, um es noch im Ersten Weltkrieg einsetzen zu können 42…”

Section: Im Kaiserreich (1877–1918)unclassified

Scope and Mechanistic Insights into the Use of Tetradecyl(trihexyl)phosphonium Bistriflimide: A Remarkably Selective Ionic Liquid Solvent for Substitution Reactions

McNulty

Nair

Cheekoori

et al. 2006

Chemistry A European J

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A survey of substitution reactions conducted in a phosphonium bistriflimide ionic liquid is presented. The results demonstrate high selectivity favoring substitution over typically competitive elimination and solvolytic processes even when challenging secondary and tertiary electrophiles are employed. The first reports of Kornblum substitution reactions in an ionic liquid are described that proceed with very high chemoselectivity in favor of nitro over nitroso products and elimination side products. The structure-reactivity study indicates that these reactions proceed through a narrow spectrum of pathways ranging from straight S(N)2 to a preassociation pathway along a saddle point that approaches the S(N)1 limit. The barrier to the formation of dissociated carbocations is attributed to the structural features of this ionic liquid that favor intervention of the associated nucleophile over dissociation, also preventing cross over to E1 processes. The lack of any basic entity in the phosphonium bistriflimide ionic liquid appears to prevent any potential base-mediated elimination reactions, which makes this a highly selective medium for use in general substitution reactions.

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“…Since those were the days of salvarsan and other arsenic‐containing medications, considerable general scientific interest existed regarding such substances. Immediately after the lifting of defense secrecy regulations in 1920 and 1923, Wieland published this work in Liebigs Annalen 40. His papers show that during the war he had already discovered diphenylaminochloroarsine (“Adamsite”), named by the Americans in honor of Roger Adams,41 one of their own “Chemical Warfare Service” experts, who near the end of the war had synthesized the material himself, albeit too late for deployment 42…”

Section: The Years Of the German Empire (1877–1918)mentioning

confidence: 99%

Interconnections and Independence: Heinrich Wieland (1877–1957) and His Era

Vaupel

2007

Angew Chem Int Ed

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The dramatic societal upheavals and radical value shifts that occurred during the first half of the 20th century influenced every aspect of life, including the scientific and research systems. A biography of Heinrich Wieland, awarded the Nobel Prize for Chemistry in 1927, one embedded in a chronicle of the times, shows clearly how this one individual adapted to multiple drastic changes in his environment.

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I. Über ringförmige Arsenverbindungen der aromatischen Reihe

Cited by 35 publications

References 1 publication

The Mechanism of Formation of Phenosafranine Dyes

The Mechanism of Formation of Phenosafranine Dyes

Scope and Mechanistic Insights into the Use of Tetradecyl(trihexyl)phosphonium Bistriflimide: A Remarkably Selective Ionic Liquid Solvent for Substitution Reactions

Interconnections and Independence: Heinrich Wieland (1877–1957) and His Era

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