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Monteiro Martins Minas da Piedade, Maria de Fátima
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- Novel "ruthenium cyclopentadienyl" - peptide conjugate complexes against human FGFR(+) breast cancerPublication . Machado, João Franco; Machuqueiro, Miguel; Marques, Fernanda; Robalo, M. Paula; Piedade, M. Fatima M.; Garcia, M. Helena; Correia, João D. G.; Morais, TâniaIn this work we explored the possibility of improving the selectivity of a cytotoxic Ru complex [RuCp(PPh3)(2,2'-bipy)][CF3SO3] (where Cp = eta(5)-cyclopentadienyl) TM34 towards FGFR(+) breast cancer cells. Molecular dynamics (MD) simulations of TM34 in a phosphatidylcholine membrane model pinpointed the cyclopentadienyl group as a favorable derivatization position for the peptide conjugation approach. Three new Ru(II) complexes presenting a functionalized eta(5)-cyclopentadienyl were synthesized, namely [Ru(eta(5)-C5H4COOH)(2,2'-bipy)(PPh3][CF3SO3] (TM281) and its precursors, [Ru(eta(5)-C5H4COOCH2CH3)(eta(2)-2,2'-bipy)(PPh3)][CF3SO3] (3) and [Ru(eta(5)-C5H4COOCH2CH3)(PPh3)(2)Cl] (2). Complex TM281 was prepared by the hydrolysis of the ethyl ester group appended to the eta(5)-cyclopentadienyl ligand of complex 3 with K2CO3 in water/acetonitrile, followed by mild protonation using an ion exchange resin. The newly synthesized complexes were fully characterized by NMR, FTIR and UV-vis spectroscopic techniques. Also, electrochemical studies were carried out by means of cyclic voltammetry in order to evaluate the stability of the compounds. Single crystal X-ray diffraction studies were carried out for compounds 3 and TM281 which crystallized in the monoclinic system, space group P21/n. The unprecedented synthesis and characterization of three half-sandwich ruthenium(II)-cyclopentadienyl peptide conjugates and their preliminary biological evaluation against human FGFR(+) and FGFR(-) breast cancer cells are also reported.
- Synthesis of Substituted 4-Arylamine-1,2-naphthoquinones in One-Pot Reactions Using CotA-Laccase as BiocatalystPublication . Sousa, Ana Catarina; Santos, Iolanda; Piedade, M. Fatima M.; Martins, Lígia O.; Robalo, M. PaulaAn efficient and environmentally benign biocatalytic strategy for the synthesis of substituted 4-arylamino-1,2-naphthoquinones was developed, through a cross-coupling reaction in which the 1,2-naphthoquinone nucleus, formed in the biocatalytic process mediated by CotA-laccase from Bacillus subtilis, is the key synthetic intermediate. Electrochemical data and kinetic parameters were determined revealing a significant higher specificity of CotA-laccase for 4-amino-3-hydroxynaphthalene-1-sulfonic acid (AHNSA). This ability of CotA-laccase to discriminate between oxidisable aromatic amines allows the set-up of one-pot reactions in the presence of the enzyme, between AHNSA and a set of appropriate aromatic amines under mild reaction conditions.