Preparation of 5-Fluoropyrazoles from Pyrazoles and <i>N</i>-Fluorobenzenesulfonimide (NFSI)

Levchenko, V. M.; Dmytriv, Yurii V.; Tymtsunik, Andriy V.; Liubchak, Konstantin; Rudnichenko, Alexander V.; Melnyk, Anton V.; Veselovych, Stanislav Y.; Borodulin, Yurii V.; Otsalyuk, Oleksandr M.; Толмачев, А. А.; Mykhailiuk, Pavel K.

doi:10.1021/acs.joc.8b00199

Cited by 15 publications

(4 citation statements)

References 64 publications

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“…In 2018, our group developed a practical synthesis of 5-fluoropyrazoles . In fact, N-protected pyrazoles were first treated with n BuLito generate a carbanionfollowed by addition of N -fluorobenzenesulfonimide (NFSI).…”

Section: Preparation Of Fluoro-substituted Pyrazolesmentioning

confidence: 99%

Fluorinated Pyrazoles: From Synthesis to Applications

2020

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Fluorinated pyrazoles play an important role in medicinal chemistry, drug discovery, agrochemistry, coordination chemistry, and organometallic chemistry. Since the early 1990s, their popularity has grown exponentially. Moreover, more than 50% of all contributions on the topic have been published in the last 5 years. In this review, analysis of novel synthetic approaches to fluorinated pyrazoles that appeared in recent years is performed. A particular emphasis is devoted to a detailed consideration of reaction mechanisms. In addition, the reasons that have led to the ever-increasing popularity of fluorinated pyrazoles in various areas of science are discussed. At the end of the review, several potentially interesting but yet mostly unknown classes of fluorinated pyrazoles are outlined.

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Section: Preparation Of Fluoro-substituted Pyrazolesmentioning

confidence: 99%

Fluorinated Pyrazoles: From Synthesis to Applications

2020

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“…Synthesis of 5-fluoropyrazoles typically occurs by reaction of (i) 1,3-dicarbonyl containing CF 3 /CF 2 (fluorinated synthon) with hydrazines followed by HF-elimination [8]; (ii) copper-catalyzed click reaction of fluorosydnones with alkynes [9]; (iii) Selectfluor and pyrazoles containing carboxylic acids followed by decarboxylation [10] and (iv) KF with pyrazoles [11,12]. The electrophilic fluorination of pyrazoles to give 5-fluoropyrazoles was recently described using N-fluorobenzenesulfonimide (NFSI) [13]. As shown in Figure 10 1-substituted pyrazoles were subjected to C5-deprotonation by lithium base, which was then fluorinated using NFSI to yield 1-substituted-5-fluoropyrazoles [13].…”

Section: C5-electrophilic Fluorination Of Pyrazolesmentioning

confidence: 99%

“…The electrophilic fluorination of pyrazoles to give 5-fluoropyrazoles was recently described using N-fluorobenzenesulfonimide (NFSI) [13]. As shown in Figure 10 1-substituted pyrazoles were subjected to C5-deprotonation by lithium base, which was then fluorinated using NFSI to yield 1-substituted-5-fluoropyrazoles [13].…”

Section: C5-electrophilic Fluorination Of Pyrazolesmentioning

confidence: 99%

Synthetic Strategies and Biological Activities of 1,5-Disubstituted Pyrazoles and 2,5-Disubstituted Thiazoles

Lozano¹,

Lewis-Bakker²,

Kotra³

2023

Strategies for the Synthesis of Heterocycles and Their Applications

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Pyrazoles and thiazoles belong to 5-membered aromatic heterocycles called azoles. In addition to a nitrogen, pyrazoles contain an additional nitrogen in a 1,2 linkage and thiazoles contain a sulfur atom in a 1,3 linkage. These compounds are useful pharmacophores that offer a broad range of therapeutic applications. Pyrazoles can be synthesized by (i) the condensation of 1,3 dipolar compounds and alkenes/alkynes, (b) cyclocondensation of hydrazines and dicarbonyl reagents, and (c) multi-component reactions. Access to thiazoles is typically via (a) the condensation of α-haloketones with nucleophilic thioamides containing the N-C-S fragment, (b) a reaction between α-aminonitriles and various reactants containing an X-C-S fragment, and (c) a reaction of acylaminocarbonyls and phosphorus pentasulfide. This chapter will focus on the strategies and our perspectives on the synthesis of pyrazoles and thiazoles including derivatives at the 1,5 positions and 2, 4, 5 positions respectively, reported during 2015–2022. Additionally, their therapeutic and biological evaluations will be discussed.

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“…Following these works, Mykhailiuk et al reported a one-pot synthesis of biologically important 5-uoropyrazoles 17 by direct lithiation/uorination of the corresponding pyrazoles 16 employing n BuLi as the lithium and NFSI as the uorine source. 32 The method was general and, as shown in Scheme 9, under the optimized conditions, various N-aryl and N-alkyl substituted pyrazole derivatives were selectively uorinated at the C5-position with moderate to good yields. However, N-alkyl pyrazoles bearing sterically bulky substituents (e.g., N-tert-butylpyrazole) failed to give the desired uorinated products.…”

Section: Transition-metal-free Reactionsmentioning

confidence: 99%