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History, synthesis, properties, applications and regulatory issues of prebiotic...
Tymczyszyn, E. E.; Santos, M. I.; Costa, Maria do Céu; Illanes, A.; Gomez-Zavaglia, A.In this chapter, the health promoting effects of carbohydrate prebiotics are addressed. A brief description of their synthesis, thermo-physical properties, mechanisms of action, technological applications and current regulatory issues are presented.
FTIR spectroscopy structural analysis of the interaction between Lactobacillus ...
Gerbino, E.; Mobili, P.; Tymczyszyn, E.; Fausto, R.; Gómez-Zavaglia, A.FTIR spectroscopy was used to structurally characterize the interaction of S-layer proteins extracted from two strains of Lactobacillus kefir (the aggregating CIDCA 8348 and the non-aggregating JCM 5818) with metal ions (Cd+2, Zn+2, Pb+2 and Ni+2). The infrared spectra indicate that the metal/protein interaction occurs mainly through the carboxylate groups of the side chains of Asp and Glut residues, with some ...
Thermally Induced Sigmatropic Isomerization of Pseudosaccharyl Allylic Ether
Gómez-Zavaglia, A.; Kaczor, A.; Almeida, R.; Cristiano, M. L. S.; Eusébio, M. E. S.; Maria, T. M. R.; Mobili, P.; Fausto, R.The thermally induced sigmatropic isomerization of the pseudosaccharyl allylic ether [3-(allyloxy)-1,2-benzisothiazole 1,1-dioxide; ABID] has been investigated by a multidisciplinary approach using temperature dependent infrared spectroscopy, differential scanning calorimetry, and polarized light thermomicroscopy, complemented by theoretical methods. Migration of the allylic system from O to N occurs in the mel...
Matrix-isolation FTIR, theoretical structural analysis and reactivity of amino-...
Almeida, R.; Gómez-Zavaglia, A.; Kaczor, A.; Ismael, A.; Cristiano, M.L.S.; Fausto, R.In this work, two novel amino-substituted derivatives of saccharin, N-(1,1-dioxo-1,2-benzisothiazol-3-yl)-N-methyl amine (MBAD) and N-(1,1-dioxo-1,2-benzisothiazol-3-yl)-N,N-dimethyl amine (DMBAD), were synthesized and characterized, and their molecular structure and vibrational properties were investigated by matrix-isolation FTIR spectroscopy and theoretical calculations undertaken using different levels of a...
First observation of Chapman rearrangement of a pseudosaccharyl ether in the so...
Almeida, R.; Gómez-Zavaglia, A.; Kaczor, A.; Cristiano, M.L.S.; Eusébio, M.E.S.; Maria, T.M.R.; Fausto, R.3-(Methoxy)-1,2-benzisothiazole 1,1-dioxide, a pseudosaccharyl ether, was long ago known to undergo a thermal Chapman-like [1,3′]-isomerization to the corresponding N-methyl pseudosaccharin at temperatures above its melting point (ca. 184 °C) [Hettler H., Tetrahedron Lett.1968, 15, 1793]. In the present study, it is shown that this rearrangement can also take place in the solid state, at temperatures as low as ...
The Chapman-type rearrangement in pseudosaccharins: The case of 3-(methoxy)-1,2...
Kaczor, A.; Proniewicz, L.M.; Almeida, R.; Gómez-Zavaglia, A.; Cristiano, M.L.S.; Beja, A.M. Matos; Silva, M. Ramos; Fausto, R.The thermal Chapman-type rearrangement of the pseudosaccharin 3-(methoxy)-1,2-benzisothiazole 1,1-dioxide (MBID) into 2-methyl-1,2-benzisothiazol-3(2H)-one 1,1-dioxide (MBIOD) was investigated on the basis of computational models and knowledge of the structure of the reactant and product in the isolated and solid phases. X-ray diffraction was used to obtain the structure of the substrate in the crystalline phas...
Characterization of S-layer proteins of Lactobacillus by FTIR spectroscopy and ...
Mobili, P.; Londero, A.; Maria, T.M.R.; Eusébio, M.E.S.; De Antoni, G.L.; Fausto, R.; Gómez-Zavaglia, A.FTIR spectroscopy was used for the characterization of S-layer proteins extracted from microorganisms isolated from kefir grains. S-layer from Lactobacillus brevis ATCC 8287 has been already characterized [G. Vidgren, I. Palva, R. Pakkanen, K. Lounatmaa, A. Palva, J. Bacteriol. 174 (1992) 7419] and therefore it was used for the validation of FTIR as a method to investigate the secondary structure of the S-layer...
Photochemistry and Vibrational Spectra of Matrix-Isolated 5-Ethoxy-1-Phenyl-1H-...
Frija, Luís M. T.; Reva, I. D.; Gómez-Zavaglia, A.; Cristiano, M. L. S.; Fausto, R.A combined matrix isolation FT-IR and theoretical DFT(B3LYP)/6-311++G(d,p) study of the molecular structure and photochemistry of 5-ethoxy-1-phenyl-1H-tetrazole (5EPT) was performed. A new method of synthesis of the compound is described. Calculations show three minima, very close in energy and separated by low-energy barriers (less than 4 kJ mol-1), in the ground-state potential energy profile of the molecule....
UV-induced photochemistry of matrix-isolated 1-phenyl-4-allyl-tetrazolone
Frija, L. M. T.; Reva, I. D.; Gómez-Zavaglia, A.; Cristiano, M. L. S.; Fausto, R.The photochemistry and molecular structure of 1-phenyl-4-allyl-tetrazolone (PAT) was studied by FT-IR matrix isolation spectroscopy and DFT(B3LYP)/6-311++G(d,p) calculations. The spectrum of matrix-isolated PAT monomers agrees well with the sum spectrum of three conformers predicted theoretically. UV irradiation (λ > 235 nm) of matrix-isolated PAT induces three types of photofragmentation: (1) production of phe...
UV-induced photochemistry of matrix-isolated 1-phenyl-4-allyl-tetrazolone
Frija, L.; Reva, I. D.; Gómez-Zavaglia, A.; Cristiano, Maria Lurdes Santos; Fausto, R.The photochemistry and molecular structure of 1-phenyl-4-allyl-tetrazolone (PAT) was studied by FT-IR matrix isolation spectroscopy and DFT(B3LYP)/6-311++G(d,p) calculations. The spectrum of matrix-isolated PAT monomers agrees well with the sum spectrum of three conformers predicted theoretically. UV irradiation (k > 235 nm) of matrix-isolated PAT induces three types of photofragmentation: (1) production of phe...
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