Selective Reduction of Nitrones and Nitroxides to Functionalized Secondary Amines

Sár, Cecı́lia P.; Kálai, Tamás; Bárácz, Nóra M.; Jerkovich, Gyula; Hideg, Kálmán

doi:10.1080/00397919508011423

Cited by 33 publications

(21 citation statements)

References 11 publications

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“…8,13 For spectroscopic identification, these products were converted to diamagnetic derivatives 12d and 13d and, for biological study, to hydroxylamines 12b and 13b, by refluxing in ethanol saturated by HCl gas, 6 or to diamine 13c, by reduction with Fe/AcOH. 14 The IR and NMR spectra suggested the 3-acyl structure instead of the 5-O-acyl derivative, as well as the findings that treatment of 13a with NaOH did not gave compound 12a as a possible hydrolysis product.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of paramagnetic and diamagnetic flavones and flavanones

Kálai¹,

Kulcsár²,

Ősz³

et al. 2004

Arkivoc

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Section: Resultsmentioning

confidence: 99%

Synthesis of paramagnetic and diamagnetic flavones and flavanones

Kálai¹,

Kulcsár²,

Ősz³

et al. 2004

Arkivoc

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“…To a stirred solution of compound 7 (997 mg, 5.0 mmol), Et 3 N (505 mg, 5.0 mmol) in dry EtOAc (10 mL) amine 8a or 8b (5.0 mmol) was added and the mixture was stirred at room temperature for 2 h. The organic phase was washed with brine (10 ml) and the organic phase was separated, dried (MgSO 4 General Procedure for Reduction of Nitroxides to Amines [24] 3b, 6b, 15.…”

Section: Methodsmentioning

confidence: 99%

Synthesis of new double (spin and fluorescence) sensor reagents and labels

Bognár

Øz

Hideg

et al. 2006

Journal of Heterocyclic Chem

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Dedicated to Prof. András Lipták on the occasion of his 70th birthday.New double (spin and fluorescence) sensors were synthesized from aminocoumarin, pyrene and 4-nitrobenzofurazan dyes and from five-or six-membered nitroxides or their diamagnetic derivatives with aromatic nucleophylic substitution, Suzuki cross-coupling reaction and acylation reactions. The new compounds exhibit fluorescence emission between 382-529 nm affording various utilization possibilities. Introduction.Fluorescent probes and sensors have attracted attention because of their high sensitivity and an exceptional ease of handling relative to their radioactive counterparts [1]. Connection of a fluorophore with a nitroxide free radical or its sterically hindered amine precursor results in a double (fluorescent and spin) sensor reagent, based on a nitroxide free radical (as an acceptor) fluorescence emission quenching of a fluorophore (as a donor) and the mechanism of the quenching has been well-documented in several cases [2,3]. The redox-status of the nitroxide or its amine precursor has a great influence on fluorescence emission intensity and this idea was utilized in design of new double sensor reagents. These reagents can be used in analytical chemistry to detect Reactive Oxygen Species (ROS) by electron spin resonance spectroscopy (EPR) and by fluorescence spectroscopy [4,5] or fluorophore attached nitroxides can be utilized as redox-indicators [6]. In our laboratory several new type donoracceptor pairs have been synthesized based on dansyl [7], aminophthalimide [8], benzazole [9] and 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) [10] type fluorophores. Till now, the most successful one has been the 3-[N-(β-diethylaminoethyl)-N-dansyl] aminomethyl-2,2,5,5-tetramethyl-2,5-dihydro-1H-pyrrole, so-called "DanePy", which is widely used in the singlet oxygen detection in plant physiology under oxidative stress conditions [11]. Another challenge in this area is the synthesis of doublelabel molecules combining advantages of the fluorescent labeling and the spin labeling. Because of the dynamic quenching in these donor-acceptor pairs, the lifetime of the

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“…Flash column chromatography was performed on a Merck (Darmstadt, Germany) Kieselgel 60 (0.040-0.063 mm). Compound 1 [16] was prepared as described previously; compound 5 was reduced to diamagnetic NH form by Fe/AcOH [22]. Other reagents were purchased from Sigma Aldrich (St. Louis, MO, USA), Alfa Aesar (Karlsruhe, Germany), Acros (Geel, Belgium), and TCI (Tokyo, Japan).…”

Section: Methodsmentioning

confidence: 99%

N-Vinylation of Imidazole and Benzimidazole with a Paramagnetic Vinyl Bromide

Úr

Fekete

Hideg

et al. 2018

Molbank

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An N-vinylation of imidazole and benzimidazole with a paramagnetic vinyl bromide was investigated. Among the tested procedures, Pd-catalyzed reaction was the most powerful one. The N-vinylation of 2-aminobenzimidazole with a β-bromo-α,β-unsaturated pyrroline nitroxide aldehyde offered 1,1,3,3-tetramethyl-1H-benzimidazo[1,2-a]pyrrolo[3,4-e]pyrimidin-2(3H)-yloxyl radical and the corresponding non-cyclized Schiff base. The reaction of a β-bromo-α,β-unsaturated pyrroline nitroxide aldehyde with imidazole gave β-imidazo-α,β-unsaturated pyrroline nitroxide aldehyde, which was reduced to the alcohol and converted to an unstable allyl chloride.

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Selective Reduction of Nitrones and Nitroxides to Functionalized Secondary Amines

Cited by 33 publications

References 11 publications

Synthesis of paramagnetic and diamagnetic flavones and flavanones

Synthesis of paramagnetic and diamagnetic flavones and flavanones

Synthesis of new double (spin and fluorescence) sensor reagents and labels

N-Vinylation of Imidazole and Benzimidazole with a Paramagnetic Vinyl Bromide

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