Synthesis of 2,3-disubstituted pyrazines and quinoxalines by Heck cross-coupling reactions of 2,3-dichloropyrazine and 2,3-dichloroquinoxaline. Influence of the temperature on the product distribution

Malik, Imran; Hussain, Munawar; Ali, Asad; Toguem, Serge‐Mitherand Tengho; Basha, Fatima Z.; Fischer, Christine; Langer, Peter

doi:10.1016/j.tet.2010.01.021

Cited by 19 publications

(14 citation statements)

References 34 publications

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“…Por outro lado, o uso de 1,25 equivalentes do alqueno leva ao produto de monoacoplamento, formado a partir da redução parcial do intermediário 2-alquil-3-cloro-quinoxalínico gerado in situ. 57 Em 2011, Joshi-Pangu e colaboradores relataram uma eficiente metodologia em que se fez o uso de haletos de alquilmagnésio terciários, utilizando ligantes NHC, sob catálise de níquel, para a obtenção de substratos com sítios quaternários arilsubstituídos, com a minimização da formação de subprodutos de isomerização. Esta metodologia pôde ser aplicada com diferentes espécies eletrofílicas, destacandose triflatos de arila e halogenetos de vinila (Esquema 55).…”

Section: Uso De Micro-ondasunclassified

C-C Cross-Coupling: New Methodologies, Applications and Discoveries over the Last Few Years

Batalha¹,

Sagrillo²,

Gama³

2014

Revista Virtual De Química

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Abstract:The possibility of obtaining new C-C bonds from the transition metals mediated catalysis, has represented a major advance in Organic Synthesis and correlated areas such as Chemistry of Natural Products and Medicinal Chemistry, since synthetically unreachable molecules could be obtained in an efficient and chemosselective way, from simple reactants. The cross-coupling reactions, as some of these processes are called, have gained prominence since the original publications of Suzuki-Miyaura, Kumada-Tamao-Corriu, Mizoroki-Heck, Sonogashira, Stille -during the 1970's -and Hiyama -in 1988. Since then numerous efforts are made by scientists around the world in order to not only understand better these processes, but also develop new catalytic systems with more efficiency and applicable to a wider range of substrates and the concepts of Green Chemistry. This work aims to expose some of the advances published by scientists around the world, in the last six years, based on this theme.Keywords: Cross coupling; new substrates; microwaves; palladium; gold. ResumoA possibilidade de se obter novas ligações C-C, a partir de reações de catálise mediadas por metais de transição, tem representado um grande avanço em Síntese Orgânica e áreas correlatas como a Química de Produtos Naturais e a Química Medicinal, uma vez que moléculas até então inalcançáveis sinteticamente puderam ser obtidas de forma eficiente e quimiosseletiva a partir de reagentes simples. As reações de acoplamento cruzado, como alguns desses processos são chamados, têm ganhado destaque desde as publicações originais de Suzuki-Miyaura, Kumada-Tamao-Corriu, Mizoroki-Heck, Sonogashira, Stille -durante a década de 1970 -e de Hiyama -em 1988. Desde então são numerosos os esforços feitos por cientistas do mundo todo no sentido de não apenas entender melhor tais processos, mas também desenvolver novos sistemas catalíticos mais eficientes e aplicáveis a uma maior variedade de substratos e aos conceitos da Química Verde. Este trabalho objetiva expor alguns dos avanços publicados por cientistas ao redor do mundo, nos últimos seis anos, com base neste tema.

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Section: Uso De Micro-ondasunclassified

C-C Cross-Coupling: New Methodologies, Applications and Discoveries over the Last Few Years

Batalha¹,

Sagrillo²,

Gama³

2014

Revista Virtual De Química

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“…24 However, all attempts to induce 6π-electrocyclization reactions of the products remained unsuccessful. …”

Section: Pyrazinesmentioning

confidence: 99%

Domino Twofold Heck/6π-Electrocyclization Reactions of 1,2-Dihaloalkenes

Hussain

Sung

Langer

2012

Synlett

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Domino twofold Heck/6π-electrocyclization reactions of 1,2-dihaloalkenes allow for a convenient synthesis of benzene derivatives. In recent years, this strategy has been applied to various 1,2-dihalogenated carbocyclic alkenes and heterocycles, and a variety of benzo-fused ring systems have been prepared. The electrocyclization reactions proceed well for five-membered, but not for six-membered heterocycles.

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“…In addition, a recent publication reported the partial or complete hydrogenation of the double bond when the reaction was carried out at high temperature, however we could not detect any hydrogenated product during this work. 23 Aryl chlorides are cheaper and more easily available than bromides and iodides, but less reactive. Efficient catalyst systems for the Heck reactions of aryl chlorides have been extensively studied.…”

Section: 10mentioning

confidence: 99%

Mizoroki-Heck cross-couplings of 2-acetyl-5-bromobenzofuran and aryl halides under microwave irradiation

Shaaban¹,

Darweesh²,

Dawood³

et al. 2010

Arkivoc

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Synthesis of 2,3-disubstituted pyrazines and quinoxalines by Heck cross-coupling reactions of 2,3-dichloropyrazine and 2,3-dichloroquinoxaline. Influence of the temperature on the product distribution

Cited by 19 publications

References 34 publications

C-C Cross-Coupling: New Methodologies, Applications and Discoveries over the Last Few Years

C-C Cross-Coupling: New Methodologies, Applications and Discoveries over the Last Few Years

Domino Twofold Heck/6π-Electrocyclization Reactions of 1,2-Dihaloalkenes

Mizoroki-Heck cross-couplings of 2-acetyl-5-bromobenzofuran and aryl halides under microwave irradiation

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