Reaction of β‐Bromo‐β,γ‐unsaturated Pyrroline Nitroxide Aldehydes and Nitriles with Aromatic<i>N</i>,<i>S</i>‐Binucleophiles

Bognár, Balázs; Varga, Bernadett; Kálai, Tamás; Csokona, Viola; Fekete, Gergely Gulyás; Sár, Cecı́lia P.; Hideg, Kálmán

doi:10.1002/jhet.2850

Cited by 1 publication

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“…Realizing that sp 2 carbon-bound thiols and selenols are oxidized by nitroxide to disulfide or diselenide, such as the case of compound 188 formation, we changed our strategy. The reaction of 2-aminothiophenol was repeated with compound 241 (the diamagnetic form of 39), which smoothly cy-clized to compound 242 that was deprotected by Zemplen's deacetylation to produce compound 243 [90]. This benzo[1,5]thiazepine can be functionalized further by reduction, alkylation and oxidation reactions to furnish compounds 244, 245, 246 (Scheme 44).…”

Section: Nitroxides Fused With Seven-membered Het-erocyclesmentioning

confidence: 99%

Synthesis and Application of Stable Nitroxide Free Radicals Fused with Carbocycles and Heterocycles

Bognár

Úr

Sár

et al. 2019

COC

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Stable nitroxide free radicals have traditionally been associated with 2,2,6,6- tetramethylpiperidine-1-oxyl (TEMPO) or its 4-substituted derivatives as relatively inexpensive and readily accessible compounds with limited possibilities for further chemical modification. Over the past two decades, there has been a resurgence of interest in stable free radicals with proper functionalization tuned for various applications. The objective of this review is to present recent results with synthetic methodologies to achieve stable nitroxide free radicals fused with aromatic carbocycles and heterocycles. There are two main approaches for accessing stable nitroxide free radicals fused with arenes, e.g., isoindoline- like nitroxides: further functionalization and oxidation of phthalimide or inventive functionalization of pyrroline nitroxide key compounds. The latter also offers the constructions of versatile heterocyclic scaffolds (furan, pyrrole, thiophene, 1,2-thiazole, selenophene, pyrazole, pyrimidine, pyridine, pyridazine, 1,5-benzothiazepine) that are fused with pyrroline or tetrahydropyridine nitroxide rings. The possible applications of these new stable nitroxide free radicals, such as covalent spin labels and noncovalent spin probes of proteins and nucleic acids, profluorescent probes, building blocks for construction of dual active drugs and electroactive materials, and substances for controlled free radical polymerization, are discussed.

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Section: Nitroxides Fused With Seven-membered Het-erocyclesmentioning

confidence: 99%