Facile Smiles‐type rearrangement in radical cations of <i>N</i>‐acyl arylsulfonamides and analogs

Irikura, Karl K.; Todua, Nino G.

doi:10.1002/rcm.6850

Cited by 8 publications

(8 citation statements)

References 34 publications

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“…Thus, N-alkyl-C-phenylnitrilium cations are the base peaks in the EI spectra of N-alkylsulfabenzamides; 34 it was established that the mechanism involves an ipso attack of the amide oxygen and further fragmentation to the thermodynamically or kinetically favored products. 36 Type a ions were observed in the EI spectra of N-methyl-N-TFA-amphetamines and a four-centered mechanism of oxygen migration has been suggested. 37 The formation of nitrilium ions with a structure of a C-alkyl-N-phenylnitrilium cation have been observed in the electrospray ionization spectra of amides of N-acetylglycine and -alanine, and a mechanism for their formation has been proposed.…”

Section: Resultsmentioning

confidence: 93%

Mass Spectrometry of Analytical Derivatives. 1. Cyanide Cations in the Spectra of N-Alkyl-N-Perfluoroacyl-α-Amino Acids and Their Methyl Esters

Todua

Tret’yakov

Mikaia

2015

Eur J Mass Spectrom (Chichester)

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The central mission for the development of the National Institute of Standards and Technology/National Institutes of Health/Environmental Protection Agency Mass Spectral Library is the acquisition of reference gas chromatography–mass spectrometry data for important compounds and their chemical modification products. The addition of reliable reference data of various derivatives of amino acids to The Library, and the study of their behavior under electron ionization conditions may be useful for their identification, structure elucidation, and a better understanding of the data obtained when the same derivatives are subjected to other ionization methods. N-Alkyl-N-perfluoroacyl derivatives of amino acids readily produce previously unreported alkylnitrilium cations of composition [HC≡N-alkyl]+. Homologous [HC≡N-aryl]+ cations are typical for corresponding N-aryl analogs. The formation of other ions characteristic for these derivatives involves oxygen rearrangement giving rise to ions [CnF2n+1–C≡N+–CnH2n+1] and [CnF2n+1–C≡N+-aryl]. The introduction of an N-benzyl substituent in a molecule favors a process producing benzylidene iminium cations. l-Threonine and l-cysteine derivatives exhibit more fragmentation pathways not typical for other α-amino acids; additionally, the Nω-amino group in l-lysine directs the dissociation process and provides structural information on the substitution at the amino functions in the molecule.

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Section: Resultsmentioning

confidence: 93%

Mass Spectrometry of Analytical Derivatives. 1. Cyanide Cations in the Spectra of N-Alkyl-N-Perfluoroacyl-α-Amino Acids and Their Methyl Esters

Todua

Tret’yakov

Mikaia

2015

Eur J Mass Spectrom (Chichester)

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“…1,4-Aryl migration to the carbonyl oxygen instead gave desulfonylated phenols. 43,44 To avert this undesired Smiles rearrangement, we synthesized N-acylsulfonamides bearing tethered alkenes that would rapidly trap the N-centered radical in a 5-exo-trig cyclization. Desulfonylative aryl migration to the incipient alkyl radical would then provide the desired arylethylamine (Fig.…”

Section: Introductionmentioning

confidence: 99%

Catalytic intramolecular aminoarylation of unactivated alkenes with aryl sulfonamides

2022

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“…The mechanism was supported by a heavy atom labeling study and density functional theory calculations . In electron ionization, a fragmentation mechanism of acylarylsulfonamide radical cations has been studied by Irikura and Todua, who concluded that it follows a Smiles-type rearrangement reaction …”

Section: Introductionmentioning

confidence: 99%

Unexpected Gas-Phase Nitrogen–Oxygen Smiles Rearrangement: Collision-Induced Dissociation of Deprotonated 2-(N-Methylanilino)ethanol and Morpholinylbenzoic Acid Derivatives

Liang

Simón‐Manso

Neta

et al. 2022

J. Am. Soc. Mass Spectrom.

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A nitrogen–oxygen Smiles rearrangement was reported to occur after collisional activation of the PhN(R)CH2CH2O– (R = alkyl) anion, which undergoes a five-membered ring rearrangement to form a phenoxide ion C6H5O–. When R = H, such a Smiles rearrangement is unlikely since the negative charge is more favorably located on the nitrogen atom than the oxygen atom; hence, alternative neutral losses dominate the fragmentation. For example, collisional activation of deprotonated 2-anilinoethanol (PhN–CH2CH2OH) leads to the formation of an anilide anion (C6H5NH–, m/z 92) rather than a phenoxide ion (C6H5O–, m/z 93.0343). However, when the amino hydrogen of 2-anilinoethanol is substituted by a methyl group, i.e., 2-(N-methylanilino)ethanol, a Smiles rearrangement does occur, leading to the phenoxide ion, as the negative charge can only reside on the oxygen atom. To confirm the Smiles rearrangement mechanism, 2-(N-methylanilino)ethanol-18O was synthesized and subjected to collisional activation, leading to an intense peak at m/z 95.0385, which corresponds to the 18O phenoxide ion ([C6H5 18O]−). The abundance of the phenoxide ion is sensitive to substituents on the N atom, as demonstrated by the observation that an ethyl substituent results in the rearrangement ion with a much lower abundance. The nitrogen–oxygen Smiles rearrangement also occurs for various morpholinylbenzoic acid derivatives with a multistep mechanism, where the phenoxide ion is found to be predominantly formed after loss of CO2, proton transfers, breaking of the morpholine ring, and Smiles rearrangement. The Smiles mechanism is also supported by density functional theory calculations and other observations.

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Facile Smiles‐type rearrangement in radical cations of N‐acyl arylsulfonamides and analogs

Cited by 8 publications

References 34 publications

Mass Spectrometry of Analytical Derivatives. 1. Cyanide Cations in the Spectra of N-Alkyl-N-Perfluoroacyl-α-Amino Acids and Their Methyl Esters

Mass Spectrometry of Analytical Derivatives. 1. Cyanide Cations in the Spectra of N-Alkyl-N-Perfluoroacyl-α-Amino Acids and Their Methyl Esters

Catalytic intramolecular aminoarylation of unactivated alkenes with aryl sulfonamides

Unexpected Gas-Phase Nitrogen–Oxygen Smiles Rearrangement: Collision-Induced Dissociation of Deprotonated 2-(N-Methylanilino)ethanol and Morpholinylbenzoic Acid Derivatives

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