Nitroxyls; VII<sup>1</sup>. Synthesis and Reactions of Highly Reactive 1-Oxyl-2,2,5,5-tetramethyl-2,5-dihydropyrrole-3-ylmethyl Sulfonates

Hankovszky, H. O.; Hideg, K.; Lex, L.

doi:10.1055/s-1980-29269

Cited by 69 publications

(55 citation statements)

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“…Synthesis of N-(1-oxyl-2,2,5,5-tetramethyl-2,5-dihydro-1H-pyrrol-3-ylmethoxy)phthal-imide radical [2]. To a stirred solution of N-hydroxyphthalimide (1.71 g, 10.5 mmol) and allylic bromide (40) [1] (10.0 mmol) in dry DMF (10 mL), Et 3N (2.02 g, 20.0 mmol) was added at 0°C, and the reddish-brown mixture was stirred at room temperature (r.t.) for 3 h and then the mixture was poured onto water (200 mL) and the precipitate was filtered, air-dried, and used without further purification in the next step. Yield: 2.58 g (82%), yellow solid, mp 158 -160°C, ., HO-4120).…”

Section: Methodsmentioning

confidence: 99%

Site-directed spin labeling of a genetically encoded unnatural amino acid

Fleissner

Brustad

Kálai

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

229

235

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The traditional site-directed spin labeling (SDSL) method, which utilizes cysteine residues and sulfhydryl-reactive nitroxide reagents, can be challenging for proteins that contain functionally important native cysteine residues or disulfide bonds. To make SDSL amenable to any protein, we introduce an orthogonal labeling strategy, i.e., one that does not rely on any of the functional groups found in the common 20 amino acids. In this method, the genetically encoded unnatural amino acid p -acetyl-L-phenylalanine ( p -AcPhe) is reacted with a hydroxylamine reagent to generate a nitroxide side chain (K1). The utility of this scheme was demonstrated with seven mutants of T4 lysozyme, each containing a single p -AcPhe at a solvent-exposed helix site; the mutants were expressed in amounts qualitatively similar to the wild-type protein. In general, the EPR spectra of the resulting K1 mutants reflect higher nitroxide mobilities than the spectra of analogous mutants containing the more constrained disulfide-linked side chain (R1) commonly used in SDSL. Despite this increased flexibility, site dependence of the EPR spectra suggests that K1 will be a useful sensor of local structure and of conformational changes in solution. Distance measurements between pairs of K1 residues using double electron electron resonance (DEER) spectroscopy indicate that K1 will also be useful for distance mapping.

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Section: Methodsmentioning

confidence: 99%

Site-directed spin labeling of a genetically encoded unnatural amino acid

Fleissner

Brustad

Kálai

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

229

235

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“…The freshly prepared chloromethyl compound 8 can be applied for irreversible SH specific labeling of proteins. To achieve reactive spin label compounds [20,21] aldehyde, 3a was reduced with NaBH 4 in EtOH at 0 • C to give alcohol 7, which was converted to allylic chloride 8 via mesylate by nucleophilic substitution with LiCl in acetone (Scheme 3). However, this compound proved to be unstable, as decomposition products appeared after several days despite low temperature (−18 • C) storage.…”

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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“…This compound, analogous to reactive nucleophilic dinitrophenylimidazoles (28), is a potentially useful reagent for biomolecules. The reaction of a free thiol nitroxide (2,2,5,5-tetramethyl-3-thiolmethyl-3-pyrrolin-1-oxyl) (29) led to the formation of a biradical 24 in a clean reaction (Scheme 2). Therefore, 3 may serve as a reagent for the spin labelling of a thiol group.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and reaction of ortho-fluoronitroaryl nitroxides. Novel versatile synthons and reagents for spin-labelling studies

Hankovszky¹,

Hideg²,

Lovas³

et al. 1989

Can. J. Chem.

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and PAL SOHAR. Can. J. Chem. 67, 1392Chem. 67, (1989.2-Flurophenyl-and 2,5-bis(fluoropheny1)pyrrolidin-1-oxyls (2 and 6) were synthesized from the corresponding nitrones 1,4, and 5 with the Grignard reagent prepared from 1-bromo-4-fluorobenzene. The reaction of 2,2,5,5-tetramethyl-3-fomyl-3-pyrrolin-1-oxyl (8) with (4-FC,&14)2Cd gave 2,2,5,5-tetramethyl-3-(a-hydroxy-4-fluorobenzy1)-3-pyrrolin-l-oxyl (9), which was oxidized with Mn02 to 2,2,5,5-tetramethyl-3-(4-fluorobenzoyl)-3-pymlin-l-oxyl(10). The aryl nitroxides 2, 6, and 10 were nitrated with concentrated H2S04/HN03 to ortho-fluoronitrophenyl compounds 3,7, and 11. The fluoro nitro derivatives served as versatile synthons in the nucleophilic replacement of fluorine with OH, NH2, a-amino acid ester, or thiol. The hydroxy nitroaryl compounds 16, 26, and 30 were nitrated further to give dinitrophenol derivatives 17, 27, and 31.

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Nitroxyls; VII¹. Synthesis and Reactions of Highly Reactive 1-Oxyl-2,2,5,5-tetramethyl-2,5-dihydropyrrole-3-ylmethyl Sulfonates

Cited by 69 publications

References 0 publications

Site-directed spin labeling of a genetically encoded unnatural amino acid

Site-directed spin labeling of a genetically encoded unnatural amino acid

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

Synthesis and reaction of ortho-fluoronitroaryl nitroxides. Novel versatile synthons and reagents for spin-labelling studies

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Nitroxyls; VII1. Synthesis and Reactions of Highly Reactive 1-Oxyl-2,2,5,5-tetramethyl-2,5-dihydropyrrole-3-ylmethyl Sulfonates

Cited by 69 publications

References 0 publications

Site-directed spin labeling of a genetically encoded unnatural amino acid

Site-directed spin labeling of a genetically encoded unnatural amino acid

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

Synthesis and reaction of ortho-fluoronitroaryl nitroxides. Novel versatile synthons and reagents for spin-labelling studies

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Nitroxyls; VII¹. Synthesis and Reactions of Highly Reactive 1-Oxyl-2,2,5,5-tetramethyl-2,5-dihydropyrrole-3-ylmethyl Sulfonates