Photosensibilisierte oxygenierung von aminen. Mechanismus der reaktion von singulett-sauerstoff mit aminen.

Gollnick, Klaus; Lindner, Jörg

doi:10.1016/s0040-4039(01)96272-0

Cited by 48 publications

(23 citation statements)

References 16 publications

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“…Therefore, the 6‐substituent on the FA molecule is oxidized and cleaved between the methylene group linked to the PT moiety and the amino group of the PABA unit (Scheme 1). The mechanism proposed by Gollnick and Lindner for the attack of 1 O 2 on primary and secondary amines bearing a nitrogen atom substituted by a CH group (31) can explain the observed reaction (Scheme 3). Accordingly, we propose that the charge‐transfer reaction occurring between the N‐10 atom and 1 O 2 leads to the oxidation of the amine (–CH 2 –NH–) to an imine (–CH = N–) with concomitant H 2 O 2 elimination.…”

Section: Resultsmentioning

confidence: 91%

Reactivity of Conjugated and Unconjugated Pterins with Singlet Oxygen (O2(1Δg)): Physical Quenching and Chemical Reaction†

Cabrerizo

Dántola

Petroselli

et al. 2007

Photochemistry and Photobiology

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Pterins (PTs) belong to a class of heterocyclic compounds present in a wide range of living systems. They participate in relevant biological functions and are involved in different photobiological processes. We have investigated the reactivity of conjugated PTs (folic acid [FA], 10-methylfolic acid [MFA], pteroic acid [PA]) and unconjugated PTs (PT, 6-hydroxymethylpterin [HPT], 6-methylpterin [MPT], 6,7-dimethylpterin [DPT], rhamnopterin [RPT]) with singlet oxygen (1O2) in aqueous solutions, and compared the efficiencies of chemical reaction and physical quenching. The chemical reactions between 1O2, produced by photosensitization, and PT derivatives were followed by UV-visible spectrophotometry and high-performance liquid chromatography, and corresponding rate constants (k(r)) were evaluated. Whenever possible, products were identified and quantified. Rate constants of 1O2 total quenching by the PT derivatives investigated were obtained from steady-state 1O2 luminescence measurements. Results show that the behavior of conjugated PTs differs considerably from that of unconjugated derivatives, and the mechanisms of 1O2 physical quenching by these compounds and of their chemical reaction with 1O2 are discussed in relation to their structural features.

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Section: Resultsmentioning

confidence: 91%

Reactivity of Conjugated and Unconjugated Pterins with Singlet Oxygen (O2(1Δg)): Physical Quenching and Chemical Reaction†

Cabrerizo

Dántola

Petroselli

et al. 2007

Photochemistry and Photobiology

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“…5) contain carbonyl and carboxyl groups, these products may also chelate with Cu(II), and the complexes may have different 1 O 2 reactivities compared with the ligands. According to Leach et al 46 and Gollnick et al, 47 1 O 2 is an electrophile that can oxidize unsaturated C]C bonds and amino N atoms. The attack of 1 O 2 is expected to primarily occur at molecular sites with the highest electron density.…”

Section: Effects Of Cu(ii) Complexation On the 1 O 2 Reactionsmentioning

confidence: 99%

Photochemical behavior of antibiotics impacted by complexation effects of concomitant metals: a case for ciprofloxacin and Cu(ii)

Wei

Chen

Xie

et al. 2015

Environ. Sci.: Processes Impacts

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Many water bodies, especially those adjacent to aquaculture and livestock breeding areas, are contaminated by both antibiotics and transition metals. However, the effects of the interaction between antibiotics and transition metals on the environmental behavior and the ecotoxicology of antibiotics are largely unknown. We hypothesized that antibiotics may coordinately bind with metal ions, and this complexation may affect the environmental photochemical behavior of antibiotics. We took ciprofloxacin (CIP) and Cu(ii) as a case, and employed simulated sunlight experiments and density functional theory calculations to investigate the underlying reaction mechanisms. The results showed that monovalent cationic ciprofloxacin (H2CIP(+)) that is predominant in the normal pH range (6-9) of surface waters can chelate with hydrated Cu(ii) to form [Cu(H2CIP)(H2O)4](3+). Compared with H2CIP(+), [Cu(H2CIP)(H2O)4](3+) has different molecular orbitals, and atomic charge distribution. As a result, [Cu(H2CIP)(H2O)4](3+) showed dissimilar light absorption properties, slower direct photolytic rates, lower (1)O2 generation ability and weaker reactivity towards (1)O2. Due to the Cu(ii) complexation, the apparent photodegradation of H2CIP(+) was inhibited, and the photolytic pathways and product distribution were altered. This study implies that for an accurate ecological risk assessment of antibiotics under transition metal co-contamination conditions, the effects of metal complexation should be considered.

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“…In contrast to unconjugated pterins, k q values for conjugated derivatives are larger than corresponding k r values ( Table 2). Two different processes may be distinguished in the chemical reaction of 1 O 2 with conjugated pterins: (a) the attack of 1 O 2 on the pterin moiety responsible for the formation of non-pterinic products as in the case of unconjugated derivatives; (b) the attack of 1 O 2 on the secondary amino group [N(12)-atom] of the PABA unit (Table 1), leading to the oxidation of the amine to an imine with concomitant H 2 O 2 elimination (reactions 8 and 9 [36]); hydrolysis of the imine group in aqueous solution induces cleavage of the 6-substituent, yielding Fop and PABA or PABAGlu as products for Pte or PteGlu, respectively. In the case of MePteGlu, the substitution of N(12) by a methyl group prevents this reaction.…”

Section: Conjugated Pterinsmentioning

confidence: 99%

Production and quenching of reactive oxygen species by pterin derivatives, an intriguing class of biomolecules

Oliveros

Dántola

Vignoni

et al. 2010

Pure and Applied Chemistry

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Pterins, a family of heterocyclic compounds derived from 2-aminopteridin-4(1H)-one, are widespread in living systems and participate in important biological functions, such as metabolic redox processes. Under UV-A excitation (320-400 nm), aromatic pterins (Pt) can generate reactive oxygen species (ROS), as a consequence of both energy-and electrontransfer processes from their triplet excited state. Quantum yields of singlet oxygen ( 1 O 2 ) production depend largely on the nature of the substituents on the pterin moiety and on the pH. Formation of the superoxide anion by electron transfer between the pterin radical anion and molecular oxygen leads to the production of significant amounts of hydrogen peroxide (H 2 O 2 ) by disproportionation. Dihydropterins (H 2 Pt) do not produce 1 O 2 but are oxidized by this species with high rate constants yielding pterins as well as H 2 O 2 . In contrast to aromatic derivatives, H 2 Pt are oxidized by H 2 O 2 , and rates and products strongly depend on the nature of the substituents on the H 2 Pt moiety. Aromatic pterins have been found in vivo under pathological conditions, e.g., biopterin or 6-carboxypterin are present in the skin of patients affected by vitiligo, a depigmentation disorder. The biomedical implications of the production of ROS by pterin derivatives and their reactivity with these species are discussed.

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Photosensibilisierte oxygenierung von aminen. Mechanismus der reaktion von singulett-sauerstoff mit aminen.

Cited by 48 publications

References 16 publications

Reactivity of Conjugated and Unconjugated Pterins with Singlet Oxygen (O2(1Δg)): Physical Quenching and Chemical Reaction†

Reactivity of Conjugated and Unconjugated Pterins with Singlet Oxygen (O2(1Δg)): Physical Quenching and Chemical Reaction†

Photochemical behavior of antibiotics impacted by complexation effects of concomitant metals: a case for ciprofloxacin and Cu(ii)

Production and quenching of reactive oxygen species by pterin derivatives, an intriguing class of biomolecules

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