DBU‐Catalyzed [3+3] and [3+2] Annulation Reactions of Azomethine Ylides with α‐Diazocarbonyls as <i>N</i>‐Terminal Electrophiles: Modular, Atom‐Economical Access to 1,2,4‐Triazine and 1,2,4‐Triazole Derivatives

Zhang, Lu; Chen, Jiajia; Liu, Sha‐Sha; Liang, Yong‐Xin; Zhao, Yu‐Long

doi:10.1002/adsc.201800030

Cited by 32 publications

(10 citation statements)

References 62 publications

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“…Furthermore, the same group also disclosed silver-catalyzed [3 + 3] cycloaddition/oxidation procedures with diazoesters and diazophosphonates to construct 3,5-dicarboxylic-1,2,4-triazines 30 and 6-phosphono-1,2,4-triazines 32 with excellent regioselectivities (parts b and c of Scheme , respectively). − These trisubstituted 1,2,4-triazines have proved to be useful in the synthesis of highly functionalized pyridines and bioorthogonal chemistry (see section ). Subsequently, Zhao and co-workers documented a similar [3 + 3] annulation reaction of diazoacetates with glycine imino esters to forge a series of tetrahydro-1,2,4-triazines, which could be oxidized by DDQ in a one-pot fashion to deliver the corresponding trisubstituted 1,2,4-triazines in moderate to good yields …”

Section: 24-triazinesmentioning

confidence: 99%

Triazines: Syntheses and Inverse Electron-demand Diels–Alder Reactions

et al. 2021

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Triazines are an important class of six-membered aromatic heterocycles possessing three nitrogen atoms, resulting in three types of regio-isomers: 1,2,4-triazines (a-triazines), 1,2,3-triazines (v-triazines), and 1,3,5-triazines (s-triazines). Notably, the application of triazines as cyclic aza-dienes in inverse electron-demand Diels–Alder (IEDDA) cycloaddition reactions has been established as a unique and powerful method in N-heterocycle synthesis, natural product preparation, and bioorthogonal chemistry. In this review, we comprehensively summarize the advances in the construction of these triazines via annulation and ring-expansion reactions, especially emphasizing recent developments and challenges. The synthetic transformations of triazines are focused on IEDDA cycloaddition reactions, which have allowed access to a wide scope of heterocycles, including pyridines, carbolines, azepines, pyridazines, pyrazines, and pyrimidines. The utilization of triazine IEDDA reactions as key steps in natural product synthesis is also discussed. More importantly, a particular attention is paid on the bioorthogonal application of triazines in fast click ligation with various strained alkenes and alkynes, which opens a new opportunity for studying biomolecules in chemical biology.

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Section: 24-triazinesmentioning

confidence: 99%

Triazines: Syntheses and Inverse Electron-demand Diels–Alder Reactions

et al. 2021

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“…A protocol for the synthesis of 1,2,4-triazole-3-carboxylates 401 from imines 399 and diazo ketones 400 was devised by Zhao and co-wrokers [ 202 ]. The reaction involved a nucleophilic attack of anion 100A , generated upon deprotonation of imine 399 with DBU, onto a terminal diazo nitrogen of 400 followed by proton transfer and tautomerization to give the hydrazone intermediate 100D .…”

Section: Azoles With Three Heteroatomsmentioning

confidence: 99%

Diazocarbonyl and Related Compounds in the Synthesis of Azoles

et al. 2021

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Diazocarbonyl compounds have found numerous applications in many areas of chemistry. Among the most developed fields of diazo chemistry is the preparation of azoles from diazo compounds. This approach represents a useful alternative to more conventional methods of the synthesis of azoles. A comprehensive review on the preparation of various azoles (oxazoles, thiazoles, imidazoles, pyrazoles, triazoles, and tetrazoles) from diazocarbonyl and related compounds is presented for the first time along with discussion of advantages and disadvantages of «diazo» approaches to azoles.

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“…该反应是基于三氟乙酰基强吸电子性的特点, 将 [24] 在此工作的基础上进一步得到了 3-全氟烷基取代的 1,2,4-三嗪酮, 例如 3-五氟乙基化和 3-七氟丙基化产物. 2017 年, 赵玉龙小组 [27] 以亚胺 83 和重氮酯 84 为原料, 在 0.5 equiv. DBU 的促进下, 得到了四氢-1,2,4-三嗪有机化学综述与进展 85, 再与 3 equiv.…”

Section: 应用unclassified

Progress in the Synthesis of 1,2,4-Triazines by Tandem Cyclization

李明瑞¹,

丁奇峰²,

李博洋³

et al. 2019

Chinese Journal of Organic Chemistry

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1,2,4-Triazine compounds are an important class of nitrogen-containing heterocyclic compounds. They have wide applications in the fields of medicine, chemicals and materials. Therefore, green and highly efficient synthesis of 1,2,4-triazine compounds is increasingly attracting the attention of researchers. By tandem cyclization reaction, the post-treatment of intermediate is avoided, and the one-pot synthesis of triazine compounds is the most efficient and direct synthesis method, which conforms to the concept of green chemistry for its step and atomic economy. The formation of C-N bond based on tandem cyclization to give 1,2,4-triazine compounds is reviewed. The synthetic method, reaction mechanism and application of 1,2,4-triazine compounds are introduced under transition-metal and metal-free conditions in the past ten years. The prospects of synthesis of triazine rings are also discussed. Keywords 1,2,4-triazine; tandem cyclization; C-N bond formation; transition-metal catalysis; metal-free catalysis 三嗪化合物 [1a] 是一类重要的含氮杂环化合物, 普遍存在于自然界中 [1b,1c] , 并且多为生物活性分子, 在医药和农药化学领域中具有巨大的应用潜力. 其中, 1,2,4-三嗪是一种用途广泛的中间体, 可用于构筑各种氮杂环类衍生物 [2a～2d] , 如 Scheme 1a 所示, 1,2,4-三嗪环可进一步与炔烃、烯烃、烯胺和酮等化合物合成吡啶类分子来构筑含氮桥环化合物 [2e～2l] , 其中与张力烯烃(如 TCO)或炔烃的反应可应用于生物正交试验. 此外, 还可作为与锕系元素(III)选择性络合的金属配体 6 以及 DNA 荧光探针 7 (Scheme 1b). 1,2,4-三嗪含有多个不饱和位点, 可以通过氢化或加成等反应, 得到具有平面或椅式等构型的三嗪类化合物, 因此是一类重要的化学合成子.

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DBU‐Catalyzed [3+3] and [3+2] Annulation Reactions of Azomethine Ylides with α‐Diazocarbonyls as N‐Terminal Electrophiles: Modular, Atom‐Economical Access to 1,2,4‐Triazine and 1,2,4‐Triazole Derivatives

Cited by 32 publications

References 62 publications

Triazines: Syntheses and Inverse Electron-demand Diels–Alder Reactions

Triazines: Syntheses and Inverse Electron-demand Diels–Alder Reactions

Diazocarbonyl and Related Compounds in the Synthesis of Azoles

Progress in the Synthesis of 1,2,4-Triazines by Tandem Cyclization

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