A Newer Synthesis of Formamidines Used as Acaricide-Insecticides

Bésán, János; Kulcsár, László; Kovács, Miklós

doi:10.1055/s-1980-29250

Cited by 21 publications

(2 citation statements)

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“…of CBr 4 , formation of the desired acetanilide 2a was observed along with formamidine 6a and CO as side products (Table , entry 3). Formamidine 6a is most likely formed by the reaction of 2a with a second molecule of the V–H reagent, indicating an excess of the formation of the active species in the reaction mixture. In addition, the release of CO gas could be confirmed by attaching a CO detector to the reactor outlet.…”

Section: Resultsmentioning

confidence: 99%

Visible Light‐Promoted Beckmann Rearrangements: Separating Sequential Photochemical and Thermal Phenomena in a Continuous Flow Reactor

2019

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The Beckmann rearrangement of oximes to amides typically requires strong acids or highly reactive, hazardous electrophiles and/or elevated temperatures to proceed. A very attractive alternative is the in situ generation of Vilsmeier–Haack reagents, by means of photoredox catalysis, as promoters for the thermal Beckmann rearrangement. Investigation of the reaction parameters for this light‐induced method using a one‐pot strategy has shown that the reaction is limited by the different temperatures required for each of the two sequential steps. Using a continuous flow reactor, the photochemical and thermal processes have been separated by integrating a flow photoreactor unit at low temperature for the electrophile generation with a second reactor unit, at high temperature, where the rearrangement takes place. This strategy has enabled excellent conversions and yields for a diverse set of oximes, minimizing the formation of side products obtained with the original one‐pot method.

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Section: Resultsmentioning

confidence: 99%

Visible Light‐Promoted Beckmann Rearrangements: Separating Sequential Photochemical and Thermal Phenomena in a Continuous Flow Reactor

2019

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“…O trabalho pioneiro foi desenvolvido por Hill, que converteu diamidas em dicloretos e imioía com pentacloreto de fósforo, reagindo em seguida com aminas primárias ou secundárias para gerar diamidinas em baixos rendimentos 51 Besán mostrou que N'-aril-N,N-dialquilformamidinas podem ser preparadas diretamente a partir de acilanilidas sem remover o grupo acila e com formação simultânea de cloretos de acila em quantidades equimolares, usando dialquilformamidas e derivado halogenado como agente de condensação. A reação ocorre a 90-100°C em até 4 h, com rendimentos entre 70 e 89%, podendo ser realizada na ausência de solvente sem alterar significativamente o rendimento 54 (Esquema 19). Haug reagiu amidas com cloretos de carboxamida, usando tolueno como solvente, para produzir amidinas em bons rendimentos 55 (Esquema 20).…”

Section: A Partir De Amidas E Tioimidatosunclassified

Principais métodos de síntese de amidinas

Santos¹,

Bernardino²,

Souza³

2006

Quím. Nova

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Recebido em 8/6/05; aceito em 6/1/06; publicado na web em 6/7/06 SYNTHETIC APPROACHES TO AMIDINES. The amidine functional group is found in a wide range of natural products and is biologically active against several pathogens. In addition, amidines have long been regarded as useful intermediates in the synthesis of heterocyclic compounds. Consequently, a great number of methods have been developed for the preparation of amidines. Pinner's method is the most commonly used. Conventional methods include: -the addition of metal amides or amines to nitriles, the addition of amines to imido esters and the condensation of amides with amines in the presence of halogenating reagents. In this report, the main methods for synthesis of amidines will be described.

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Recent advances in the synthesis of amidines

Boyd

1991

PATAI'S Chemistry of Functional Groups

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A Newer Synthesis of Formamidines Used as Acaricide-Insecticides

Cited by 21 publications

References 0 publications

Visible Light‐Promoted Beckmann Rearrangements: Separating Sequential Photochemical and Thermal Phenomena in a Continuous Flow Reactor

Visible Light‐Promoted Beckmann Rearrangements: Separating Sequential Photochemical and Thermal Phenomena in a Continuous Flow Reactor

Principais métodos de síntese de amidinas

Recent advances in the synthesis of amidines

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