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1.
Analyst ; 144(5): 1704-1710, 2019 Feb 25.
Article in English | MEDLINE | ID: mdl-30657475

ABSTRACT

The superoxide anion (O2˙-) plays a crucial role in several physiological processes and many human diseases. Developing new methods for O2˙- detection in biological systems is very important. A FRET-based two-photon (TP) fluorescent probe with a ratiometric signal, TFR-O, was developed. A naphthalene derivative based TP fluorescent group was selected as the energy donor group, and a rhodol fluorescent group was chosen as the energy acceptor; the trifluoromethanesulfonate group was chosen as the recognition moiety. After reacting with O2˙-, the recognition moiety was removed and the fluorophore was released, leading to a fluorescence intensity decrease at the wavelength of 425 nm and a significant enhancement of the fluorescence intensity at 550 nm. The fluorescence intensity ratio between 550 and 425 nm (I550/I425) varied from 0.15 to 6.72, with the O2˙- concentration increasing from 0 to 50 µM. The detection limit of the TFR-O was 83 nM. Moreover, TFR-O was applied for detecting and imaging O2˙- in cells and liver tissues.


Subject(s)
Fluoresceins/chemistry , Fluorescent Dyes/chemistry , Mesylates/chemistry , Naphthalenes/chemistry , Superoxides/analysis , Animals , Fluoresceins/chemical synthesis , Fluoresceins/radiation effects , Fluoresceins/toxicity , Fluorescence , Fluorescence Resonance Energy Transfer/methods , Fluorescent Dyes/chemical synthesis , Fluorescent Dyes/radiation effects , Fluorescent Dyes/toxicity , Limit of Detection , Liver/metabolism , Mesylates/chemical synthesis , Mesylates/radiation effects , Mesylates/toxicity , Mice , Naphthalenes/chemical synthesis , Naphthalenes/radiation effects , Naphthalenes/toxicity , Photons , RAW 264.7 Cells , Superoxides/metabolism
2.
Org Biomol Chem ; 16(13): 2214-2218, 2018 03 28.
Article in English | MEDLINE | ID: mdl-29528082

ABSTRACT

A convenient, oxidant-free protocol was developed for the ortho trifluoromethylation of aniline via picolinamide assisted Fe-promoted C-H functionalization under ultraviolet irradiation. In this transformation acetone essentially acted as both a solvent to dissolve reactants and a low-cost radical initiator to efficiently generate a CF3 radical from Langlois' reagent. A broad substrate scope was tolerated and picolinamide bearing strong electron withdrawing groups also could be transformed into the corresponding products with acceptable yields. Furthermore, the value of this method has been highlighted via the efficient synthesis of the nonsteroidal anti-inflammatory drug floctafenine.


Subject(s)
Aniline Compounds/chemistry , Iron/chemistry , Picolinic Acids/chemistry , Acetone/chemistry , Amides/chemistry , Anti-Inflammatory Agents, Non-Steroidal/chemical synthesis , Catalysis , Hydrocarbons, Fluorinated/chemistry , Hydrocarbons, Fluorinated/radiation effects , Indicators and Reagents/chemistry , Indicators and Reagents/radiation effects , Mesylates/chemistry , Mesylates/radiation effects , Methylation , Models, Chemical , Ultraviolet Rays , ortho-Aminobenzoates/chemical synthesis
3.
Chemosphere ; 138: 988-94, 2015 Nov.
Article in English | MEDLINE | ID: mdl-25563159

ABSTRACT

The photocatalytic degradation of the herbicide sulcotrione (0.05 mM) and its formulated compound Tangenta® in aqueous suspensions of TiO2 Degussa P25 was examined as a function of the different operational parameters. The optimum of the catalyst loading was found to be 2.0 mg mL(-1) under UVA light. In the first stage of the reaction, the photocatalytic degradation of sulcotrione alone and in Tangenta® followed the pseudo-first order kinetics, in which the heterogeneous catalysis proceeds via OH and holes. Further, it can be concluded that degradation rate of sulcotrione alone is about two times higher compared to formulated compound. The results showed that the disappearance of sulcotrione led to the formation of three organic intermediates and ionic byproducts (Cl(-), SO4(2-), acetate and formate), whereas their mineralization was about 90% after 4 h. Tentative photodegradation pathways were proposed and discussed. Also, there was no significant toxicity observed after the irradiation of sulcotrione solution and Tangenta® formulation using TiO2 catalyst on three mammalian cell lines.


Subject(s)
Cyclohexanones/isolation & purification , Light , Mesylates/isolation & purification , Photolysis , Titanium/chemistry , Water Pollutants, Chemical/isolation & purification , Water Purification/methods , Animals , Catalysis , Cell Line , Cell Survival/drug effects , Cyclohexanones/radiation effects , Cyclohexanones/toxicity , Humans , Kinetics , Mesylates/radiation effects , Mesylates/toxicity , Solutions , Suspensions , Water Pollutants, Chemical/radiation effects , Water Pollutants, Chemical/toxicity
4.
Water Res ; 41(8): 1781-9, 2007 Apr.
Article in English | MEDLINE | ID: mdl-17303209

ABSTRACT

Photochemical behaviour of sulcotrione, a triketone herbicide, was studied in a variety of aqueous solutions including natural waters (sea and river) under laboratory conditions. Photodegradation experiments were carried out under two irradiation systems (UV-B and simulated solar radiation) in order to evaluate kinetics of active ingredient. The degradation kinetics, more rapid under UV-B radiation than solar simulator, followed a first-order reaction (photolysis half-lives ranged between 3 and 50 h) and appeared strongly dependent on water origin, pH value and molecular structure of the herbicide. Dissolved organic matter showed a retarding effect while low concentrations of nitrate ions had no effect on photolysis rate. Identification of photoproducts indicated that hydrolysis, a pH-dependent process (no degradation at pH >6 but at pH=3, k=0.0344 h(-1)), could be photoassisted. These results were compared to those of mesotrione, another triketone herbicide, which appeared more stable under UV-B irradiation. Toxicological studies on two marine heterotrophic bacteria and one cyanobacterium showed absence of effects up to 100 microgL(-1) for both sulcotrione and its photoproducts.


Subject(s)
Cyclohexanones/radiation effects , Herbicides/radiation effects , Mesylates/radiation effects , Ultraviolet Rays , Water Pollutants, Chemical/radiation effects , Carbon/analysis , Cyclohexanones/toxicity , Halomonas/drug effects , Halomonas/growth & development , Herbicides/toxicity , Hydrogen-Ion Concentration , Mesylates/toxicity , Nitrates/analysis , Nitrites/analysis , Phosphates/analysis , Photolysis , Rivers , Seawater , Synechocystis/drug effects , Synechocystis/growth & development , Vibrio/drug effects , Vibrio/growth & development , Water Pollutants, Chemical/toxicity
6.
Photochem Photobiol Sci ; 4(1): 83-8, 2005 Jan.
Article in English | MEDLINE | ID: mdl-15616696

ABSTRACT

Photochemical reaction profiles of a photoacid generator, N-trifluoromethylsulfonyloxy-1,8-naphthalimide (NI-Sf), in solution phase were investigated by means of picosecond and nanosecond transient absorption spectroscopy as well as transient grating measurements. Picosecond transient absorption spectroscopy directly revealed that the lifetime of the S1 state and the intersystem-crossing yield decreased with increasing solvent polarity. On the other hand, photochemical reaction yield increased with an increase in the solvent polarity. These results indicated that the photochemical reaction started in the S1 state. Transient grating measurement directly detected the diffusion process of the proton and its diffusion coefficient was obtained to be 3.9 x 10(-9) m2 s(-1), which was several times larger than those of the usual solute molecules.


Subject(s)
Imides/chemistry , Mesylates/chemistry , Solutions/chemistry , Acids/chemistry , Imides/radiation effects , Kinetics , Lasers , Mesylates/radiation effects , Naphthalimides , Photochemistry , Photolysis , Spectrophotometry/instrumentation , Spectrophotometry/methods , Time Factors
7.
Photochem Photobiol ; 61(4): 360-6, 1995 Apr.
Article in English | MEDLINE | ID: mdl-7740079

ABSTRACT

In order to understand its mechanism of action we have begun an effort to better define the cellular target of action of the experimental antitumor agent DMP 840 (NSC D640430; (R,R)-2,2'-(1,2-ethanediylbis(imino-(1-methyl-2,1-ethanediyl)))-bi s(5- nitro-1H-benz(de)isoquinoline-1,3-(2H)-dione) dimethanesulfonate). Using a combination of gentle cell fractionation procedures and a previously unidentified photochemical crosslinking reaction, we have shown that after the drug is added to cultured Clone A cells, more than 80% of the drug that is found associated with cells partitions to the chromatin-containing structural framework of the cell and that the primary target after crosslinking with 360 nm light is DNA. While DMP 840 photoreacts quite efficiently with purified RNA in vitro, no photoattachment of the drug to RNA was observed in cells. In vitro photochemical studies also reveal that while GC-rich DNA is a preferred target for drug interaction, AT-rich DNA is more active in the photochemical crosslinking reaction. These results suggest that DMP 840 probably kills cells by interfering with DNA-metabolic processes, and that the drug and its derivatives are likely to be useful photoactive molecular probes for investigating higher order chromatin structures in cells.


Subject(s)
Antineoplastic Agents/metabolism , Isoquinolines/metabolism , Mesylates/metabolism , Animals , Antineoplastic Agents/pharmacology , Antineoplastic Agents/radiation effects , Binding Sites , Cattle , Cell Fractionation , Cross-Linking Reagents , DNA/metabolism , Humans , In Vitro Techniques , Isoquinolines/pharmacology , Isoquinolines/radiation effects , Mesylates/pharmacology , Mesylates/radiation effects , Photochemistry , Polynucleotides/metabolism , Tumor Cells, Cultured
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