Construction of 1,2,4-Triazole Derivatives via Cyclocondensation of Alkylidene Dihydropyridines and Aryldiazonium Salts

Joshi, Madhur S.; Pigge, F. Christopher

doi:10.1021/acs.orglett.6b03019

Cited by 31 publications

(26 citation statements)

References 40 publications

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“…Clearly, both indazole and 1,2,4-triazole are valuable heterocyclic structures. Their derivatives are a versatile class of compounds found in numerous natural products and biologically active compounds.…”

supporting

confidence: 62%

Diazo Activation with Diazonium Salts: Synthesis of Indazole and 1,2,4-Triazole

Wei

et al. 2020

Org. Lett.

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A donor/acceptor diazo activation strategy, processing via condensation using diazonium salts without the addition of any other catalysts or reagents, is reported. The diazenium intermediate was found to undergo cyclization to give indazoles in excellent yields. Alternatively, in the presence of nitriles, substituted 1,2,4-triazoles were obtained in good to excellent yields. This interesting diazenium route provides a new approach to achieve complex heterocycle synthesis under mild conditions.

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confidence: 62%

Diazo Activation with Diazonium Salts: Synthesis of Indazole and 1,2,4-Triazole

Wei

et al. 2020

Org. Lett.

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“…In 2016, the Pigge group developed a novel and efficient synthetic approach to pyridyl-substituted 1,2,4-triazoles and triazolium salts via cyclocondensation of alkylidene dihydropyridines and aryldiazonium salts (Scheme 26). [38] The alkylidene dihydropyridines (anhydrobases) which were generated in situ from pyridines and ClCO 2 Et in THF participated in [3 + 2] cyclocondensation reactions with aryldiazonium cations to afford functionalized 1,2,4-triazolium salts and 1,2,4-triazoles in moderate to good yields. High atom economy, readily available starting materials, good functional group tolerance, and mild reaction conditions render this protocol attractive for the construction of 1,2,4-triazole containing bioactive molecules.…”

Section: Synthesis Of 124-triazoles and Their Derivativesmentioning

confidence: 99%

Recent Advances in the Synthesis of Nitrogen Heterocycles Using Arenediazonium Salts as Nitrogen Sources

et al. 2020

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Nitrogen heterocycles are important structural subunits that occur widely in bioactive natural products, pharmaceuticals, agrochemicals, dyes, cosmetics, and functional materials. Considering the importance of these useful compounds in modern science, the synthesis of N-heterocycles and their derivatives has always been a hot topic in organic synthesis. Recently, arenediazonium salts which can be easily prepared from inexpensive and abundantly available anilines, have been used as versatile nitrogen sources in the field of nitrogen heterocycle synthetic chemistry due to their ready availability, rich reactivity, and diverse transformations. The aim of the present review is to summarize the recent advances in the synthesis of nitrogen heterocycles using arenediazonium salts as nitrogen sources in the past ten years. Hopefully, it can provide practical guidance for the readers who are interested in utilizing arenediazonium salts as building blocks in organic synthesis. For simplicity and clarity, the organization of this review is based on the number of N atoms in the ring of nitrogen heterocycle.

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“…Finally, we found that the exocyclic alkenes in pyridine anhydrobases (III) are amenable to reactions before rearomatization to form other valuable pyridine derivatives (Scheme 2). [14] After subjecting 3-phenylpyridine N-triazinyl salt to the dearomatization-olefination sequence, we used the crude material containing III-3-Ph without purification.…”

Section: Methodsmentioning

confidence: 99%

Four‐Selective Pyridine Alkylation via Wittig Olefination of Dearomatized Pyridylphosphonium Ylides

2021

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Methods to synthesize alkylated pyridines are valuable because these structures are prevalent in pharmaceuticals and agrochemicals. We have developed a distinct approach to construct 4-alkylpyridines using dearomatized pyridylphosphonium ylide intermediates in a Wittig olefination-rearomatization sequence. Pyridine N-activation is key to this strategy, and N-triazinylpyridinium salts enable coupling between a wide variety of substituted pyridines and aldehydes. The alkylation protocol is viable for late-stage functionalization, including methylation of pyridine-containing drugs. This approach represents an alternative to metal-catalyzed sp 2 -sp 3 cross-coupling reactions and Minisci-type processes. Scheme 1. Design plan for pyridine alkylation via Wittig olefinationrearomatization of pyridylphosphonium ylides.

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Construction of 1,2,4-Triazole Derivatives via Cyclocondensation of Alkylidene Dihydropyridines and Aryldiazonium Salts

Cited by 31 publications

References 40 publications

Diazo Activation with Diazonium Salts: Synthesis of Indazole and 1,2,4-Triazole

Diazo Activation with Diazonium Salts: Synthesis of Indazole and 1,2,4-Triazole

Recent Advances in the Synthesis of Nitrogen Heterocycles Using Arenediazonium Salts as Nitrogen Sources

Four‐Selective Pyridine Alkylation via Wittig Olefination of Dearomatized Pyridylphosphonium Ylides

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