Synthesis of 2-trifluoromethylpyrazolo[5,1-<i>a</i>]isoquinolines via silver triflate-catalyzed or electrophile-mediated one-pot tandem reaction

Zhou, Xiaoli; Liu, Meiling; Luo, Puying; Lai, Yingjun; Yang, Tangtao; Ding, Qiuping

doi:10.3762/bjoc.10.238

Cited by 9 publications

(2 citation statements)

References 29 publications

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“…After reductive elimination, intermediates 123 undergo a 5-endo-dig-cyclization to give 124, followed by subsequent aromatization to form the final H-pyrazolo[5,1-a]isoquinolines 116 (Scheme 41). 61 2-Trifluoromethylpyrazolo 62 In the case of the silver triflate-catalyzed cyclization of compounds 106 in the presence of the in situ generated pyridyne 127 from 126, the corresponding regioisomeric H-pyrazolo[5,1-a]isoquinolines 128 and 129 were prepared in modest yields (Scheme 43). 63a Polyfluoroarenes react with N′-(2-alkynylbenzylidine) hydrazide 106 catalyzed by silver triflate in the presence of cesium carbonate leading to polyfluoroaryl-fused H-pyrazolo-[5,1-a]isoquinolines in good yields.…”

Section: Isoquinolinium-n-aryl Imidesmentioning

confidence: 99%

1,3-Dipolar cycloadditions of azomethine imines

2015

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Azomethine imines are considered 1,3-dipoles of the aza-allyl type which are transient intermediates and should be generated in situ but can also be stable and isolable compounds. They react with electron-rich and electron-poor olefins as well as with acetylenic compounds and allenoates mainly by a [3 + 2] cycloaddition but they can also take part in [3 + 3], [4 + 3], [3 + 2 + 2] and [5 + 3] with different dipolarophiles. These 1,3-dipolar cycloadditions (1,3-DC) can be performed not only under thermal or microwave conditions but also using metallo- and organocatalytic systems. In recent years enantiocatalyzed 1,3-dipolar cycloadditions have been extensively considered and applied to the synthesis of a great variety of dinitrogenated heterocycles with biological activity. Acyclic azomethine imines derived from mono and disubstituted hydrazones could be generated by prototropy under heating or by using Lewis or Brønsted acids to give, after [3 + 2] cycloadditions, pyrazolidines and pyrazolines. Cyclic azomethine imines, incorporating a C-N bond in a ring, such as isoquinolinium imides are the most widely used dipoles in normal and inverse-electron demand 1,3-DC allowing the synthesis of tetrahydro-, dihydro- and unsaturated pyrazolo[1,5-a]isoquinolines in racemic and enantioenriched forms with interesting biological activity. Pyridinium and quinolinium imides give the corresponding pyrazolopyridines and indazolo[3,2-a]isoquinolines, respectively. In the case of cyclic azomethine imines with an N-N bond incorporated into a ring, N-alkylidene-3-oxo-pyrazolidinium ylides are the most popular stable and isolated dipoles able to form dinitrogen-fused saturated and unsaturated pyrazolopyrazolones as racemic or enantiomerically enriched compounds present in many pharmaceuticals, agrochemicals and other useful chemicals.

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Section: Isoquinolinium-n-aryl Imidesmentioning

confidence: 99%

1,3-Dipolar cycloadditions of azomethine imines

2015

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“…Ding and co‐workers established a one‐pot trifluoromethylated pyrazolo[5,1‐ a ]isoquinoline 70 synthesis through AgOTf (Lewis acid)‐catalyzed strategy [46] . Diverse isoquinolines were generated by a tandem annulation followed by a [3+2] cycloaddition reaction of N ’‐(2‐alkynylbenzylidene)hydrazides 55 with ethyl 4,4,4‐trifluorobut‐2‐ynoate 69 (Scheme 38).…”

Section: Six Membered Heterocycles With One Heteroatommentioning

confidence: 99%

An Overview of Ag‐catalyzed Synthesis of Six‐membered Heterocycles

et al. 2020

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Heterocyclic chemistry is an immensely expanding field in organic synthesis owing to its potency in various disciplines like natural products chemistry, pharmaceuticals, drug discovery and industry. Silver catalysis has gained much attraction in recent years mainly in the scenario of heterocyclic synthesis. Among heterocycles, the six membered heterocycles are the most popular and widely applied in various fields. This review discusses on the investigations on various silver‐catalyzed synthesis of six‐membered heterocycles and covers literatures up to 2020.

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Silver‐Catalyzed Cyclizations

Wong

Hii

2018

Silver Catalysis in Organic Synthesis

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Synthesis of 2-trifluoromethylpyrazolo[5,1-a]isoquinolines via silver triflate-catalyzed or electrophile-mediated one-pot tandem reaction

Cited by 9 publications

References 29 publications

1,3-Dipolar cycloadditions of azomethine imines

1,3-Dipolar cycloadditions of azomethine imines

An Overview of Ag‐catalyzed Synthesis of Six‐membered Heterocycles

Silver‐Catalyzed Cyclizations

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