Dye-sensitized photooxygenation of the carbon-nitrogen double bond

Castro, Claire; Dixon, Michael; Erden, İhsan; Ergonenc, P.; Keeffe, James R.; Sukhovitsky, A.

doi:10.1021/jo00276a042

Cited by 27 publications

(14 citation statements)

References 2 publications

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“…3A, entries 6 and 7). Taking these experimental data and previous literature into account, [76][77][78][79] we propose a tentative mechanism for the photoactivation of oxime-caged uorophores. When irradiated by light, oxime-caged uorophores are activated to the intermediate bi-radical species A*.…”

Section: Mechanism Of Oxime-caged Uorophore Activationsupporting

confidence: 57%

“…An alternative mechanism may involve the regeneration of bi-radical intermediates when imine and oxime compounds are exposed to direct irradiation. [76][77][78][79] We investigated this type of radical-mediated mechanism for the photoactivation of oxime-caged uorophores. Knowing that 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) is a free radical scavenger, we found that the addition of TEMPO dramatically inhibits the photoactivation of oxime-caged uorophores (Fig.…”

Section: Mechanism Of Oxime-caged Uorophore Activationmentioning

confidence: 99%

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Oxime as a general photocage for the design of visible light photo-activatable fluorophores

et al. 2021

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Section: Mechanism Of Oxime-caged Uorophore Activationsupporting

confidence: 57%

Section: Mechanism Of Oxime-caged Uorophore Activationmentioning

confidence: 99%

Oxime as a general photocage for the design of visible light photo-activatable fluorophores

et al. 2021

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“…Mp 78-81 C (lit. 45 Table 1, entry 10) 24,52, 54 Method A. The condensation reaction between aldehyde 1g and N-methylhydroxylamine hydrochloride 2 afforded 72 mg of 14 as a white solid in 96% yield.…”

Section: Methods B: Microwave Conditions (Only For Nitrones 3 6-8 Anmentioning

confidence: 99%

Solvent-free synthesis of nitrones in a ball-mill

et al. 2008

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Various C-aryl and C-alkyl-nitrones were synthesized within 0.5-2 h via condensation of an equimolar amount of aldehydes and N-substituted-hydroxylamines under solvent-free conditions in a ball-mill apparatus. Reactions can be performed without the need of excluding air and moisture and yields the expected products with no need for further purification. The study has been complemented by Differential Scanning Calorimetry (DSC) and solid-state 13 C MAS nuclear magnetic resonance experiments. We have also studied the temperature profile during the reaction. A comparative study with the corresponding solvent-free microwave activated reaction showed the superiority of the ball-milling method; 31 examples are described, including the synthesis of the anti-aging agent C-phenyl-N-tert-butyl nitrone (PBN) and one of its analogues C-2-pyridyl-N-tert-butylnitrone (2-PyBN).

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“…In this study, our goal was to theoretically study the reaction of formalhydrazone 1 with singlet oxygen ( 1 D g O 2 , abbreviated here as 1 O 2 ), to gain a sense of the energetics required for nitrosamine release. Reactions of N-methyl-N-phenylhydrazones of p-tolualdehyde and p-acetyltoluene with 1 O 2 have led to nitrosamine and carbonyl products at À78°C in CCl 4 or CH 2 Cl 2 (1,2). The reaction of 1 O 2 with hydrazones such as glucosazone or N,N-dimethylhydrazone has led to carbonyl compounds under mild conditions (3)(4)(5)(6).…”

Section: Introductionmentioning

confidence: 99%

Theoretical Study of the Reaction Formalhydrazone with Singlet Oxygen. Fragmentation of the C=N Bond, Ene Reaction and Other Processes

Rudshteyn

Castillo

Ghogare

et al. 2013

Photochem & Photobiology

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Photobiologic and synthetic versatility of hydrazones has not yet been established with 1O2 as a route to commonly encountered nitrosamines. Thus, to determine whether the “parent” reaction of formalhydrazone and 1O2 leads to facile C=N bond cleavage and resulting nitrosamine formation, we have carried out CCSD(T)//DFT calculations and analyzed the energetics of the oxidation pathways. A [2 + 2] pathway occurs via diradicals and formation of 3-amino-1,2,3-dioxazetidine in a 16 kcal/mol process. Reversible addition or physical quenching of 1O2 occurs either on the formalhydrazone carbon for triplet diradicals at 2–3 kcal/mol, or on the nitrogen (N(3)) atom forming zwitterions at ~15 kcal/mol, although the quenching channel by charge-transfer interaction was not computed. The computations also predict a facile conversion of formalhydrazone and 1O2 to hydroperoxymethyl diazene in a low-barrier ‘ene’ process, but no 2-amino-oxaziridine-O-oxide (perepoxide-like) intermediate was found. A Benson-like analysis (group increment calculations) on the closed shell species are in accord with the quantum chemical results.

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Dye-sensitized photooxygenation of the carbon-nitrogen double bond

Cited by 27 publications

References 2 publications

Oxime as a general photocage for the design of visible light photo-activatable fluorophores

Oxime as a general photocage for the design of visible light photo-activatable fluorophores

Solvent-free synthesis of nitrones in a ball-mill

Theoretical Study of the Reaction Formalhydrazone with Singlet Oxygen. Fragmentation of the C=N Bond, Ene Reaction and Other Processes

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