Encontrados 38 documentos, a visualizar página 1 de 4
Acridinyl methyl esters as photoactive precursors in the release of neurotransm...
Piloto, Ana M.; Hungerford, Graham; Costa, Susana P. G.; Gonçalves, M. Sameiro T.An investigation of the use of an azaheterocycle, acridine, as an alternative photochemically removable protecting group for the carboxylic function of neurotransmitter amino acids was carried out. 9-Bromomethylacridine was used in the reaction with glycine, alanine, glutamic acid, β-alanine and γ-aminobutyric acid, to obtain model ester derivatives, which were irradiated at different wavelengths in a photochem...
Photorelease of amino acids from novel thioxobenzo[f]benzopyran ester conjugates
Piloto, Ana M.; Soares, Ana M. S.; Costa, Susana P. G.; Gonçalves, M. Sameiro T.Aiming at the enhancement of the performance of (9-methoxy-3-oxo-3H-benzo[f]benzopyran-1-yl) methyl ester as photocleavable protecting group for the carboxylic acid function at long-wavelengths, 9-methoxy-3-thioxo-3H-benzo[f]benzopyran-L-valine and L-phenylalanine model conjugates were prepared through a thionation reaction of the corresponding oxo-benzobenzopyrans. These thioxobenzobenzopyran derivatives were ...
Synthesis, characterization, photophysical studies and interaction with DNA of ...
Pedras, Bruno; Batista, Rosa M. F.; Tormo, Laura; Costa, Susana P. G.; Raposo, M. Manuela M.; Orellana, Guillermo; Capelo, José Luis; Lodeiro, CarlosA new family of Ru(II) polypyridyl complexes (C1 to C6) containing furyl- or thienyl-imidazo-phenanthroline ligands (4-6) were synthesized using microwave irradiation and characterized by elemental analysis, 1H-NMR, UV-vis absorption and fluorescence spectroscopy, FAB, EI-MS and MALDI-TOF-MS spectrometry. On the other hand, the novel furyl- or thienyl-imidazo-phenanthroline derivatives (5-6) were synthesized th...
Phototriggering of neuroactive amino acids from 5,6-benzocoumarinyl conjugates
Fernandes, Maria José G.; Costa, Susana P. G.; Gonçalves, M. Sameiro T.Uncaging of several neuroactive amino acids, namely β-alanine, tyrosine, 3,4-dihydroxyphenylalanine (DOPA) and glutamic acid from the corresponding 5,6-benzocoumarinyl conjugates was carried out by irradiation at different wavelengths and in different solvent systems. The release of the various amino acids was faster in ACN/HEPES buffer mixtures and for the tyrosine conjugate, an increase in the photolysis reac...
Photolysis at long wavelengths of amino acid ester derivatives based on 4-methy...
Piloto, Ana M.; Soares, Ana M. S.; Hungerford, Graham; Costa, Susana P. G.; Gonçalves, M. Sameiro T.Ester derivatives of fused 4-methyl-6-methoxy-2-oxo-2H- naphtho[1,2-b]pyran, using valine and phenylalanine as model bifunctional molecules were synthesised, to assess its applicability as a photocleavable protecting group, for solution phase organic synthesis and in caging applications, at longer wavelengths. The behaviour of the corresponding derivatives towards photolysis was evaluated by irradiation in mixt...
Synthesis and characterization of novel push-pull thiophene and thienylpyrrole ...
Batista, Rosa M. F.; Costa, Susana P. G.; Belsley, M.; Raposo, M. Manuela M.The synthesis and characterization of new chromophores with second-order nonlinearities containing thienylpyrrole 1a, 2a-b, bithiophene 3 and arylthiophene 4 as π-conjugated bridges and indanonedicyanovinyl acceptor group are reported. The effect of placing the acceptor group at thiophene or pyrrole rings on the optoelectronic properties was also evaluated for thienylpyrrole derivatives 1a and 2a-b. The linear ...
Imidazo-benzo-15-crown-5 ether bearing arylthienyl and bithienyl moieties as no...
Batista, Rosa M. F.; Oliveira, Elisabete; Costa, Susana P. G.; Lodeiro, Carlos; Raposo, M. Manuela M.Novel fluorescent ionophores bearing imidazo-arylthienyl or imidazo-bithienyl pi-conjugated bridges functionalized with one or two fused benzo-15-crown-5 ethers as receptor units are reported. The sensing ability of the compounds in the presence of metallic cations (Li+, Na+, K+, Ca2+, Zn2+, Cu2+, Ni2+, Pd2+ and Hg2+) and fluoride ion was studied in MeCN/DMSO solutions by absorption and emission spectroscopy. T...
(Oligo)thienyl-imidazo-benzocrown ether derivatives : synthesis, photophysical ...
Batista, Rosa M. F.; Oliveira, Elisabete; Costa, Susana P. G.; Lodeiro, Carlos; Raposo, M. Manuela M.; Ferreira, R. Cristina M.A series of novel (oligo)thienyl-imidazobenzocrown ethers were synthesised through a simple method and evaluated as fluorimetric chemosensors for transition metal cations. Interaction with Ni2+, Pd2+, and Hg2+ in ACN/DMSO solution (99:1) was studied by absorption and emission spectroscopy. Chemoselectivity studies in the presence of Na+ were also carried out and a fluorescence enhancement upon chelation (CHEF) ...
Novel highly emissive non proteinogenic amino acids : synthesis of 1,3,4-thiadi...
Esteves, Cátia I. C.; Raposo, M. Manuela M.; Costa, Susana P. G.Highly emissive heterocyclic asparagine derivatives bearing a 1,3,4-thiadiazolyl unit at the side chain, functionalised with electron donor or acceptor groups, were synthesised and evaluated as amino acid based fluorimetric chemosensors for metal cations such as Cu2+, Zn2+, Co2+ and Ni2+. The results suggest that there is a strong interaction through the donor heteroatoms at the side chain of the various aspara...
Exploring the emissive properties of new azacrown compounds bearing aryl, furyl...
Oliveira, Elisabete; Baptista, Rosa M. F.; Costa, Susana P. G.; Raposo, M. Manuela M.; Lodeiro, CarlosThree new compounds bearing furyl, aryl or thienyl moieties linked to an imidazo-crown ether system (1, 2 and 3) were synthesized and fully characterized by elemental analysis, infrared, absorption and emission spectroscopy, X-ray crystal diffraction, and MALDI-TOF-MS spectrometry. The interaction towards metal ions (Ca2+, Cu2+, Ni2+ and Hg2+) and F- has been explored in solution by absorption and fluorescence ...
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