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21.
Beverina L Abbotto A Landenna M Cerminara M Tubino R Meinardi F Bradamante S Pagani GA 《Organic letters》2005,7(19):4257-4260
[graph: see text] Condensation of squaric acid with a number of differently substituted 2-pyrrolyl derivatives afforded three new classes of squaraines. Their sharp and intense absorption bands in the biological window (700-900 nm), inherent singlet oxygen generation capabilities, together with proper functionalization allowing good water solubility make them suitable candidates as new non-porphyrinic singlet oxygen photosensitizers for photodynamic therapy (PDT). 相似文献
22.
Francesco De Sarlo Antonio Guarna Andrea Goti Alberto Brandi 《Journal of organometallic chemistry》1984,269(2):115-121
Organomercury fulminates react with acetylene derivatives to give unstable 3-(organomercurio)isoxazoles, which isomerize to 2-cyanoenolates. These are hydrolyzed with hydrochloric acid to the corresponding enols and are cleaved by water at the double bond. With monosubstituted acetylenes, substitution at the free position by the organomercury residue is predominant. 相似文献
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24.
Alessandro Boido Francesco Savelli Fernando Sancassan 《Journal of heterocyclic chemistry》1997,34(5):1643-1644
Following a previous experiment, an original heteropolycyclic structure 4 was obtained by a reaction of chloroacetyl chloride with compound 3 bearing a conjugated double bond system. The condensation develops with an initial NH-chloroacetylation and ring closure by quaternarization of the pyridine nitrogen. This is achieved through an 1,4 -cycloaddition of chloroketene to make a pyranone ring. 相似文献
25.
Marino Cavazza Gioia Morganti Antonio Guerriero Francesco Pietra 《Tetrahedron letters》1980,21(38):3703-3704
EtO? in DMSO adds to ethylthiopicrate at C-3 to generate an ephemeral -adduct which ends into 1-ethylthio-4-ethoxy-2,5-dinitrobenzene, whilst ethyl picrate gives two adducts of attack of EtS? at C-3 or C-1. 相似文献
26.
Hypocotyl growth in etiolated seedlings of wild-type and an aurea mutant of tomato (Lycopersicon esculenturn Mill.), that appears to be deficient in labile phytochrome, is strongly inhibited by UV radiation in the region of 300–400 nm. The role of phytochrome in the UV-mediated inhibition of hypocotyl growth was studied using different experimental approaches: (1) by comparing the effectiveness of treatments of increasing duration of exposure to 692 nm and UV radiation; (2) by modifying the UV spectral range with specific cut-off filters. The experimental results suggest that the UV-induced inhibition of growth in wild-type tomato is mediated to a large extent by the longer wavelengths of the UV-A region and is mediated mainly by phytochrome. In contrast, at wavelengths < 305 nm a strong UV-B effect was found in the aurea mutant, suggesting a preeminent action of a specific UV-B absorbing photoreceptor that displays less action in the wild-type. 相似文献
27.
28.
Maly J Di Meo C De Francesco M Masci A Masojidek J Sugiura M Volpe A Pilloton R 《Bioelectrochemistry (Amsterdam, Netherlands)》2004,63(1-2):271-275
Electrochemical synthesis of nickel-nitrilotriacetic acid (Ni-NTA) chelators, for subsequent immobilization of (His)(6)-tagged proteins (Photosystem II (PSII) as model molecule), on Au or Au-graphite electrodes is compared to chemical synthesis. Results show: (i) higher Ni-NTA surface density, (ii) shorter treatment time (1-12 min vs. 16 h normally needed for self-assembled monolayer (SAM)), (iii) possibility of addressing the chelator to only one Au electrode, in a sensor micro-array. 相似文献
29.
Peroxidase based biosensors for the selective determination of D,L-lactic acid and L-malic acid in wines 总被引:1,自引:0,他引:1
A novel bioelectrochemical method for the direct determination of D(−) L(+) lactic acid and of L(−) malic acid in wines is presented. Multienzymatic biosensors were realized for the selective determination of the three analytes: D(−) and L(+) lactic acid were measured by a trienzymatic biosensor based on the catalytic activities of the enzymes L(+) lactate oxidase (LOD), D(−) lactate dehydrogenase (D-LDH) and horseradish peroxidase (HRP); L(−) malic acid was measured by a bienzymatic electrode, realized by coupling the enzymes L(−) malic dehydrogenase (L-MDH) and horseradish peroxidase (HRP). In both cases the enzymes were immobilized on an oxygen selective Clark electrode.The simultaneous determination of the two organic acids can be accomplished either in batch or in a flow injection analysis apparatus using the same biosensors as detectors. The analytical performance of the method, tested in standard aqueous solutions and on real samples of wines, showing high repeatability, short response times and reduced cost of analysis, suggest that the experimental approach here described could be followed to monitor the progress of malolactic fermentation. 相似文献
30.
Radical anions of nitrobenzothiazoles: EPR study of conjugative properties of benzothiazolyl systems
Francesco Ciminale 《Tetrahedron letters》2004,45(30):5849-5852
The electrochemical reduction in DMSO of the five isomers of nitrobenzothiazole (NBTZ) gave quite persistent radical anions that could be easily characterised by EPR spectroscopy. By contrast, the chemical reduction in alkaline solution, that is by t-BuOK in DMSO or by glucose and MeOK in MeOH, presented some problems with 6- and 4-NBTZ, and in the case of 2-NBTZ did not provide any detectable paramagnetic species. The internal consistency of coupling constants of the nitrobenzothiazole radical anions is in good agreement with the conjugative properties of the various benzothiazolyl systems and allows rectifying a recent EPR characterisation of 6-NBTZ radical anion. 相似文献