On the photoreactivity of vitamin K compounds

Swartz, Angela; Patton, Valerie; Heppleston, Marianne J.; Barra, Mónica

doi:10.1002/kin.20356

Cited by 4 publications

(4 citation statements)

References 30 publications

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“…RF and CBBP have several analogies with known CDOM components, , while the 1NN triplet state is less reactive than that of AQ2S and it is very conveniently studied by laser flash photolysis. , Indeed, the study of the reactivity of 3 1NN*, 3 RF*, and 3 CBBP* with PRP required the use of a laser apparatus, which was also used to measure again the second-order reaction rate constant between PRP and 3 AQ2S*. It has been reported that the measured laser and steady-irradiation 3 AQ2S* second-order rate constants are very similar in the case of nitrobenzene, , but the laser apparatus might also detect physical quenching phenomena that do not lead to chemical reactions and are not taken into account by steady irradiation . Moreover, in some cases the initial substrate is reformed during steady irradiation by a combination of oxidation and reduction processes. , The experimental laser flash photolysis data obtained in this work are summarized in Figure S10.…”

Section: Resultsmentioning

confidence: 99%

“…It has been reported that the measured laser and steady-irradiation 3 AQ2S* second-order rate constants are very similar in the case of nitrobenzene, 59,60 but the laser apparatus might also detect physical quenching phenomena that do not lead to chemical reactions and are not taken into account by steady irradiation. 61 Moreover, in some cases the initial substrate is reformed during steady irradiation by a combination of oxidation and reduction processes. 62,63 The experimental laser flash photolysis data obtained in this work are summarized in Figure S10.…”

Section: ■ Introductionmentioning

confidence: 99%

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Phototransformation of the Herbicide Propanil in Paddy Field Water

Carena

Minella

Barsotti

et al. 2017

Environ. Sci. Technol.

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When irradiated in paddy-field water, propanil (PRP) undergoes photodegradation by direct photolysis, by reactions with OH and CO, and possibly also with the triplet states of chromophoric dissolved organic matter. Irradiation also inhibits the nonphotochemical (probably biological) degradation of PRP. The dark- and light-induced pathways can be easily distinguished because 3,4-dichloroaniline (34DCA, a transformation intermediate of considerable environmental concern) is produced with almost 100% yield in the dark but not at all through photochemical pathways. This issue allows an easy assessment of the dark process(es) under irradiation. In the natural environment, we expect PRP photodegradation to be important only in the presence of elevated nitrate and/or nitrite levels, e.g., [NO] approaching 1 mmol L (corresponding to approximately 60 mg L). Under these circumstances, OH and CO would play a major role in PRP phototransformation. Because flooded paddy fields are efficient denitrification bioreactors that can achieve decontamination of nitrate-rich water used for irrigation, irrigation with such water would both enhance PRP photodegradation and divert PRP dissipation processes away from the production of 34DCA, at least in the daylight hours.

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Section: Resultsmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Phototransformation of the Herbicide Propanil in Paddy Field Water

Carena

Minella

Barsotti

et al. 2017

Environ. Sci. Technol.

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“…[67][68][69] A partir dos trabalhos pioneiros de Porter, vários estudos com fotólise por pulso e isolamento cromatográfico permitiram a identificação de intermediários e de produtos decorrentes de reações fotoquímicas de Fotoisomerização de filoquinona em pentano degasado. 70,71 Há mais de 60 anos, em um trabalho sobre "β-oxidação da cadeia lateral de hidróxi-naftoquinonas", Ettlinger menciona que lapachol (encontrado na madeira do ipê, 72,73 A fotoquímica do lapachol voltou a ser estudada recentemente por Gorner: 60 o rendimento quântico de formação de 1 O 2 é desprezível; foi detectada a presença, por fotólise por pulso de laser, do intermediário 1,3-QM, que evolui a 1,2-QM e, daí, a produtos propostos -pois um único produto encontrado por c.l.a.e. (cromatografia líquida de alta eficiência) não teve sua estrutura "identificada ou investigada" Apesar da reação ocorrer a partir do estado excitado singlete e triplete de cetonas, a regio-e estereoseletividade da reação dependem da multiplicidade do estado excitado.…”

Section: Figura 17 Fotoquímica De Derivados Da Lausonaunclassified

Photochemistry of Naphthoquinones

Lucas¹,

Ferreira²,

Netto‐Ferreira³

2015

Revista Virtual De Química

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Quinones are widely distributed in living organisms, are present in medicines and used as reagents by chemists. In nature, certain benzoquinones are so commonly found that they are called ubiquinones (ubiquitous); others, the plastoquinones, participate in the process of photosynthesis, without being directly excited by light. These processes will not be seen here. The participation of excited quinones in the generation of singlet oxygen and other reactive oxygen species (ROS) will be addressed. The photochemistry of quinones, which are colored compounds, has been studied since the mid-XIX century, with Klinger; in Part 1, after the Introduction, we will present a summary of the most relevant results, so far, mainly for naphthoquinones, starting with fundamental concepts of organic photochemistry of ketones. We will see, for example, how biological quinones can, when excited by light, deactivate without generating harmful reactive species. In Part 2 some of the spectroscopic techniques with lasers, used in contemporary photochemistry will be reviewed. And, finally, these techniques will be applied to the study of naphthoquinones related to natural products and the results will be discussed.

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“…For natural compounds, photochemical-induced formation of an o -QM intermediate was also reported for 2-isoprenyl-3-methyl-1,4-naphthoquinones, such as vitamin K derivatives . For example, the photoredox reaction of menaquinone 1 (vitamin K2) or phylloquinone (vitamin K1) leads, after 1,4-proton transfer, to a zwitterionic species that tautomerizes to a metastable isomeric o -QM.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Photochemical Properties of Fluorescent Metabolites Generated from Fluorinated Benzoylmenadiones in Living Cells

et al. 2023

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This work describes the reactivity and properties of fluorinated derivatives (F-PD and F-PDO) of plasmodione (PD) and its metabolite, the plasmodione oxide (PDO). Introduction of a fluorine atom on the 2-methyl group markedly alters the redox properties of the 1,4-naphthoquinone electrophore, making the compound highly oxidizing and particularly photoreactive. A fruitful set of analytical methods (electrochemistry, absorption and emission spectrophotometry, and HRMS-ESI) have been used to highlight the products resulting from UV photoirradiation in the absence or presence of selected nucleophiles. With F-PDO and in the absence of nucleophile, photoreduction generates a highly reactive ortho-quinone methide (o-QM) capable of leading to the formation of a homodimer. In the presence of thiol nucleophiles such as β-mercaptoethanol, which was used as a model, o-QMs are continuously regenerated in sequential photoredox reactions generating mono- or disulfanylation products as well as various unreported sulfanyl products. Besides, these photoreduced adducts derived from F-PDO are characterized by a bright yellowish emission due to an excited-state intramolecular proton transfer (ESIPT) process between the dihydronapthoquinone and benzoyl units. In order to evidence the possibility of an intramolecular coupling of the o-QM intermediate, a synthetic route to the corresponding anthrones is described. Tautomerization of the targeted anthrones occurs and affords highly fluorescent stable hydroxyl-anthraquinones. Although probable to explain the intense visible fluorescence emission also observed in tobacco BY-2 cells used as a cellular model, these coupling products have never been observed during the photochemical reactions performed in this study. Our data suggest that the observed ESIPT-induced fluorescence most likely corresponds to the generation of alkylated products through reduction species, as demonstrated with the β-mercaptoethanol model. In conclusion, F-PDO thus acts as a novel (pro)-fluorescent probe for monitoring redox processes and protein alkylation in living cells.

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On the photoreactivity of vitamin K compounds

Cited by 4 publications

References 30 publications

Phototransformation of the Herbicide Propanil in Paddy Field Water

Phototransformation of the Herbicide Propanil in Paddy Field Water

Photochemistry of Naphthoquinones

Synthesis and Photochemical Properties of Fluorescent Metabolites Generated from Fluorinated Benzoylmenadiones in Living Cells

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