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A novel VIVO–pyrimidinone complex: synthesis, solution speciation and human ser...
Gonçalves, Gisela; Tomaz, Isabel; Correia, Isabel; Vieiros, Luís F.; Castro, M. M. C. A.; Avecilla, Fernando; Palacio, Lorena; Maestro, MiguelThe pyrimidinones mhcpe, 2-methyl-3H-5-hydroxy-6-carboxy-4-pyrimidinone ethyl ester (mhcpe, 1), 2,3- dimethyl-5-benzyloxy-6-carboxy-4-pyrimidinone ethyl ester (dbcpe, 2) and N-methyl-2,3-dimethyl-5- hydroxy-6-carboxyamido-4-pyrimidinone (N-MeHOPY, 3), are synthesized and their structures determined by single crystal X-ray diffraction. The acid–base properties of 1 are studied by potentiometric and spectrophotom...
Binding of oxovanadium(IV) complexes to blood serum albumins
Cobbina, Enoch; Mehtab, Sameena; Correia, Isabel; Gonçalves, Gisela; Tomaz, Isabel; Cavaco, Isabel Maria Palma Antunes; Jakusch, Tamás; Eneyedi, EvaIn this work the binding of VIVO2+ and VIVO-complexes to serum albumins {human serum albumin (HSA), bovine serum albumin (BSA) and porcine serum albumin (PSA)} are studied using circular dichroism (CD), electron paramagnetic resonance (EPR) and visible absorption spectroscopy. The results confirm previous findings that VIVO2+ occupies at least two types of binding sites on albumin: ‘the strong vanadium binding ...
Tricarbonyl M(I) (M = Re, 99mTc) complexes bearing acridine fluorophores : synt...
Esteves, Teresa; Xavier, Catarina; Gama, Sofia; Mendes, Filipa; Raposinho, Paula D.; Marques, Fernanda; Paulo, António; Pessoa, João Costa; Rino, José© The Royal Society of Chemistry 2010 ; New pyrazolyl-diamine ligands with acridine derivatives at the 4-position of the pyrazolyl ring were synthesized and characterized (L1 and L2). Coordination towards the fac-[M(CO)3]+ (M = Re, 99mTc) led to complexes fac-[M(CO)3(κ3-L)] (L = L1: M = Re1, Tc1; L = L2: M = Re2, Tc2). The interaction of the novel pyrazolyl-diamine ligands (L1 and L2) and rhenium(I) complexes ...
Vanadium (IV and V) Complexes of Reduced Schiff Bases Derived from the Reaction...
Pessoa, João Costa; Marcão, Susana; Correia, Isabel; Gonçalves, Gisela; Dörnyei, Agnes; Kiss, Tamás; Jakusch, Tamás; Tomaz, IsabelThe reduced Schiff bases of salicylaldehyde [and o-vanillin (o-van)] with D,L- and L-diaminopropionic acid (DPA), designated by salDPA, and L-2,4-diaminopentanoic acid [ornithine (Orn)], designated by salOrn, as well as the VIVO2+ and VVO2+ complexes of salDPA were prepared. The compounds were characterised in the solid state and in solution. The structure of H4salDPA+Cl- was determined by X-ray diffraction. Co...
Uptake and metabolic effects of insulin mimetic oxovanadium compounds in human ...
Delgado, Teresa C.; Tomaz, A. Isabel; Correia, Isabel; Pessoa, João Costa; Jones, John G.; Geraldes, Carlos F. G. C.; Castro, M. Margarida C. A.The uptake of the oxidation products of two oxovanadium(IV) compounds, [N,N'-ethylenebis(pyridoxylaminato)]oxovanadium(IV), VIVO(Rpyr2en), and bis-[3-hydroxy-1,2-dimethyl-4-pyridinonato]oxovanadium(IV), VIVO(dmpp)2, by human erythrocytes was studied using 51V and 1H NMR and EPR spectroscopy. VIVO(Rpyr2en) in aerobic aqueous solution is oxidized to its VV counterpart and the neutral form slowly enters the cells ...
Vanadium(IV and V) Complexes of Schiff Bases and Reduced Schiff Bases Derived f...
Correia, Isabel; Pessoa, João Costa; Duarte, M. Teresa; Piedade, M. Fátima Minas da; Jackush, Tamás; Kiss, Tamás; Castro, M. Margarida C. A.Several sal2en-type reduced Schiff bases have been prepared from the reaction of 2 equiv. of salicylaldehyde (or derivatives) with ethylenediamine followed by reduction with NaBH4 and subsequently characterised. The water-soluble ligands (SO3-sal)2en and R(SO3-sal)2en (SO3-sal = salicylaldehyde-5-sulphonate) have been studied by pH potentiometry and 1H NMR spectroscopy and the protonation constants of R(SO3-sal...
N,N'-Ethylenebis(pyridoxylideneiminato) and N,N'-Ethylenebis(pyridoxylaminato):...
Correia, Isabel; Pessoa, João Costa; Duarte, M. Teresa; Henriques, Rui T.; Piedade, M. Fátima M.; Veiros, Luís F.; Jakusch, Tamás; Kiss, TamásThe Schiff base N,Nprime-ethylenebis(pyridoxylideneiminato) (H2pyr2en, 1) was synthesized by reaction of pyridoxal with ethylenediamine; reduction of H2pyr2en with NaBH4 yielded the reduced Schiff base N,Nprime-ethylenebis(pyridoxylaminato) (H2Rpyr2en, 2); their crystal structures were determined by X-ray diffraction. The totally protonated forms of 1 and 2 correspond to H6L4+, and all protonation constants wer...
Novel Asymmetric Wittig Reaction: Synthesis of Chiral Allenic Esters
Melo, Teresa M. V. D. Pinho e; Cardoso, Ana L.; Gonsalves, António M. d'A. Rocha; Pessoa, João Costa; Paixão, José A.; Beja, Ana M.Wittig reactions between 10-(phenylsulfonyl)isobornyl (triphenylphosphoranylidene)acetates (1 and 6) and ketenes resulted in asymmetric induction, with the selective synthesis of allenes with axial chirality. Use of the (1R)-(-)-10-(phenylsulfonyl)isoborneol unit allows the synthesis of allenes with S configuration, whereas use of the (1S)-(+)-10-(phenylsulfonyl)isoborneol unit produces allenes with R configura...
Contribution to the synthesis of chiral allenic esters
Melo, Teresa M. V. D. Pinho e; Cardoso, Ana L.; Gonsalves, António M. D'A. Rocha; Storr, Richard C.; Pessoa, João Costa; Paixão, José A.; Beja, Ana M.A phosphorus ylide bearing a 10-phenylsulfonylisoborneol unit reacted with ketenes, generated in situ from acid chlorides and triethylamine, to give allenic compounds. The reaction with methylketene led to asymmetric induction with the selective synthesis of an allene with axial chirality corresponding to an S configuration. The structure of the chiral allene 10-phenylsulfonylisobornyl penta-2,3-dienoate was de...
Synthesis of Chiral Pyrrolo[1,2-c]thiazoles via Intramolecular Dipolar Cycloadd...
Melo, Teresa M. V. D. Pinho e; Soares, Maria I. L.; Gonsalves, António M. d'A. Rocha; Paixão, José A.; Beja, Ana M.; Silva, Manuela RamosIntramolecular dipolar cycloaddition of bicyclic münchnones, 5H,7H-thiazolo[3,4-c]oxazol-4-ium-1-olates, derived from cyclodehydration of 2-substituted-N-acylthiazolidine-4-carboxylic acids are reported. A range of new pyrrolo[1,2-c]thiazole derivatives (7, 14, 15, 20, 23, and 26) were obtained as single enantiomers from 2-phenylthiazolidines, 2-benzoylthiazolidines, and 2-methylthiazolidine-4-carboxylates. Pyr...
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