Jose Montejo-Bernardo - Academia.edu (original) (raw)
Papers by Jose Montejo-Bernardo
Acta Crystallographica Section A Foundations and Advances, 2015
Computers and Electronics in Agriculture, 2014
ABSTRACT Currently, the process of accrediting a certain crop to become a Protected Designation o... more ABSTRACT Currently, the process of accrediting a certain crop to become a Protected Designation of Origin (PDO) valid one for the fabrication of Sidra de Asturias implies the visual inspection of the crop by technicians who ensure that there are only PDO valid varieties. It becomes then necessary a rapid, non-destructive, easy-to-use, cheap, trustable and efficient method to objectively classify the crop in order to detect possible frauds or human unintentional errors in the identification. Rapid methods for identification of different apple varieties based on Attenuated Total Reflectance (ATR)–Fourier Transform Infrared fingerprint spectroscopy assisted by Linear Discriminant Analysis (LDA) and by Artificial Neural Networks (ANN) have been developed. For each assayed variety, different sections of clean apple skins were selected and scanned from 600 cm�1 to 4000 cm�1. Apple data extracted from FTIR spectroscopy were gathered, analyzed and the final 372 reduced spectra were randomly distributed into training data sets (70%) and test data sets (30%). The classification results based on the LDA model gave a higher success rate (95.0%) than the ANN algorithm (85.5%) in the test data sets, although ANN presented a lower incorrect classification rate (1.9%) vs. LDA (5.0%). The ATR–FTIR technique coupled to chemometric approaches demonstrated to be useful, rapid, cheap and easy-to-use for identifying apple varieties. Success rate is better in LDA than in ANN, although ANN has a lower error rate because of its ability to detect ‘unclassifiable’ samples. These methods may be a helpful industrial approach to ensure the adequate selection of apple varieties to obtain a perfectly-balanced product under the PDO standards.
Acta Crystallographica Section A Foundations of Crystallography, 2009
Journal of Solid State Chemistry, 2000
Three non-isostructural metal(II) coordination polymers (metal=copper, cobalt, cadmium) were synt... more Three non-isostructural metal(II) coordination polymers (metal=copper, cobalt, cadmium) were synthesized under the same mild hydrothermal conditions (T=408K) by mixture of the corresponding metal acetate with 2-carboxyethylphosphonic acid and 1,10-phenanthroline (1:1:1 M ratio) and their structures were determined by single-crystal X-ray diffraction. Cu2(HO3PCH2CH2COO)2(C12H8N2)2(H2O)2 and Cd2(HO3PCH2CH2COO)2(C12H8N2)2 are triclinic (space group P-1) with a=7.908(5)Å, b=10.373(5)Å, c=11.515(5)Å, α=111.683(5)°, β=95.801(5)°, γ=110.212(5)° (T=120K), and a=8.162(5)Å, b=9.500(5)Å,
Journal of Solid State Chemistry, 2015
Organic Letters, 2007
The chemical synthesis and enzymatic desymmetrization of a panel of prochiral diamines have been ... more The chemical synthesis and enzymatic desymmetrization of a panel of prochiral diamines have been successfully described for the first time using lipases in organic solvents. A family of 2-aryl-1,3-propanediamines has been obtained with high enantiopurity and good yields in the PSL-catalyzed reaction using diallyl carbonate in 1,4-dioxane.
ChemCatChem, 2014
ABSTRACT Alcohol dehydrogenases (ADHs) were identified as suitable enzymes for the reduction of t... more ABSTRACT Alcohol dehydrogenases (ADHs) were identified as suitable enzymes for the reduction of the corresponding α,α-dihalogenated ketones, obtaining optically pure β,β-dichloro- or β,β-dibromohydrins with excellent conversions and enantiomeric excess. Among the different biocatalysts tested, ADHs from Rhodococcus ruber (ADH-A), Ralstonia sp. (RasADH), Lactobacillus brevis (LBADH), and PR2ADH proved to be the most efficient ones in terms of activity and stereoselectivity. In a further study, two racemic α-substituted ketones, namely α-bromo- α-chloro- and α-chloro-α-fluoroacetophenone were investigated to obtain one of the four possible diastereoisomers through a dynamic kinetic process. In the case of the brominated derivative, only the (1R)-enantiomer was obtained by using ADH-A, although with moderate diastereomeric excess (>99 % ee, 63 % de), whereas the fluorinated ketone exhibited a lower stereoselectivity (up to 45 % de).
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Zeitschrift für anorganische und allgemeine Chemie, 2003
ABSTRACT Copper(II) complexes of new N-benzothiazole sulfonamides (HL1= N-2-(benzothiazole)naphta... more ABSTRACT Copper(II) complexes of new N-benzothiazole sulfonamides (HL1= N-2-(benzothiazole)naphtalensulfonamide and HL2 = N-2-(6-chlorobenzothiazole)toluenesulfonamide) with ethylenediamine (en) and diethylenetriamine (dien) have been synthesized and characterised. The crystal structures of [Cu(dien)2](L1)2 (1) and [Cu(en)2(H2O)2](L2)2 (2) compounds have been determined. The metal centre adopts a “4+2” distorted octahedral environment in both complexes. Unusually, the sulfonamidate anions act as counterions. Spectroscopic properties are in good agreement with the crystal structures. The superoxide dismutase (SOD)-like activity of complex 2 has been tested.Kupfer(II)-Polyamin-Komplexe mit N-Benzothiazol-Sulfonamidaten als Gegenionen — Synthese, Kristallstrukturen und Eigenschaften von [Cu(dien)2](L1)2[HL1 = N-2-(Benzothiazol)naphthalinsulfonamid, dien = diethylentriamin] und [Cu(en)2(H2O)2](L2)2 [HL2 = N-2-(6-Chlorbenzothiazol)toluolsulfonamid, en = Ethylendiamin] — Superoxid-Dismutase-AktivitätKupfer(II)-Komplexe neuer N-Benzothiazol-Sulfonamide (HL1 = N-2-(Benzothiazol)naphthalinsulfonamid und HL2 = N-2-(6-Chlorbenzothiazoltoluolsulfonamid) mit Ethylendiamin (en) und Diethylentriamin (dien) wurden synthetisiert und charakterisiert. Die Kristallstrukturen von [Cu(dien)2](L1)2 (1) und [Cu(en)2(H2O)2](L2)2 (2) wurden ermittelt. Die Metallzentren weisen eine verzerrt oktaedrische „4+2”-Koordination auf. Ungewöhnlich ist die Funktion der Sulfonamidat-Anionen als Gegenionen. Die spektroskopischen Eigenschaften sind in guter Übereinstimmung mit den Kristallstrukturen. Die Superoxid-Dismutase-Aktivität (SOD) von Komplex 2 wurde ermittelt.
Tetrahedron: Asymmetry, 2006
An efficient chemoenzymatic route for the synthesis of optically active substituted indolines has... more An efficient chemoenzymatic route for the synthesis of optically active substituted indolines has been developed. Different lipases have been tested in the alkoxycarbonylation of these secondary amines, Candida antarctica lipase A (CAL-A) was found to be the best biocatalyst for 2-substituted-indolines, and C. antarctica lipase B (CAL-B) for 3-methylindoline. The combination of lipases with a variety of allyl carbonates and
Tetrahedron: Asymmetry, 2014
ABSTRACT Prop-2-en-1-yl[(1S,2R)-2-amino-1,2-bis(3-bromophenyl)ethyl]carbamateC18H18Br2N2O2Ee = 14... more ABSTRACT Prop-2-en-1-yl[(1S,2R)-2-amino-1,2-bis(3-bromophenyl)ethyl]carbamateC18H18Br2N2O2Ee = 14% (HPLC, Column Chiralcel OJ-H)[α]D20=+1.2 (c 0.5, EtOH)Source of chirality: Lipase-catalyzed desymmetrization with CAL-AAbsolute configuration: (1S,2R)
Tetrahedron, 2009
The chemical preparation and stereoselective enzymatic desymmetrization of a series of prochiral ... more The chemical preparation and stereoselective enzymatic desymmetrization of a series of prochiral 2-substituted-1,3-propanediamines have been carried out using Pseudomonas cepacia lipase as biocatalyst. Syntheses of novel optically active orthogonally protected di- or triamines have been achieved for the first time with different grade of enantiodiscrimination depending on the C-2 substitution of the propane-1,3-diamine fragment. Final monoselective deprotection reactions of (S)-3-allyl-2-tert-butyl-1-(9-fluorenylmethyl)propane-1,2,3-triyltriscarbamate
Zeitschrift für Kristallographie, 2003
A combination of X-ray powder diffraction and single crystal studies on azithomycin pseudopolymor... more A combination of X-ray powder diffraction and single crystal studies on azithomycin pseudopolymorphs give the precise solid state composition of all monohydrate pseudopolymorphs reported. According to the X-ray results the four monohydrates of azithromycin studied have the same crystallographic parameters. Furthermore, the analysis of the relative intensities from the powder patterns points to very similar chemical compositions and crystal structures. This result has been confirmed by the single crystal studies. The single crystal studies show that the solid state conformation of the azithromycin molecules is affected by the presence of solvents. The solvent methanol molecules were found disordered probably due to the existence of many positions where the hydrogen bonding is favoured and the large size of the available space to host the solvents.
Zeitschrift für Kristallographie, 2000
The structure of a new semihydrate solvated form of the antibiotic azithromycin is reported. The ... more The structure of a new semihydrate solvated form of the antibiotic azithromycin is reported. The new form was obtained by partial dehydration of the crystal of the monohydrate-i-PrOH, when the sample was left in laboratory conditions (295-298 K, 55-65% relative humidity) over a long period of time (about 40 months). The new semihydrate solvate form retains the crystalline structure of the monohydrate (unit cell parameters and space group) but shows changes in the position of the hydrogen atoms of some OH groups of the azithromycin molecules, leading to a new and different hydrogen bonding network. Moreover, in one of the two azithromycin molecules in the asymmetric unit (the one labelled as "b"), the dimethylamine group (in the desosamine sugar) shows a significant positional change. This fact provides information about the role of the solvent in the building of the solvated forms of the azithromycin drug, and allows the mobility of this group to be associated with an inversion operation and not a rotation. Scheme 1. Solvated forms of azithromycin.
Zeitschrift für Kristallographie, 2005
This paper describes the crystal structure of the azithromycin monohydrate pseudopolymorph (pseud... more This paper describes the crystal structure of the azithromycin monohydrate pseudopolymorph (pseudopolymorphic forms, different solvates of the same chemical compound, azithromycin in our case) crystallised from isopropanol, solved by X-ray single crystal, and called isopropanol clathrate monohydrate (Apotex, US 6,245,903). The powder diffraction patterns for this compound show a structure very similar to the azithromycin monohydrate crystallised from ethanol, called stable monohydrate (Biochemie, WO 0100640), and the X-ray single crystal confirms the fact that this new pseudopolymorph is isostructural to the previously reported, the referred stable monohydrate.
Journal of Inorganic Biochemistry, 2003
Two new mu-methoxo-bridged dinuclear copper(II) complexes with a N-substituted sulfonamide, [Cu(m... more Two new mu-methoxo-bridged dinuclear copper(II) complexes with a N-substituted sulfonamide, [Cu(mu-OMe)(L)(NH(3))](2) (1) and [Cu(mu-OMe)(L)(DMSO)](2) (2) [HL, N-2-(4-methylbenzothiazole)benzenesulfonamide], have been prepared and characterized by single-crystal X-ray difraction analyses. Compound 1 crystallizes in the monoclinic space group C(2)/c with a=22.0678(18), b=7.9134(7), c=21.1186(18)A, beta=113.788(4) degrees and Z=8. Compound 2 crystallizes in the monoclinic space group C(2)/c with a=18.0900(10), b=9.5720(10), c=24.2620(10) A, beta=98.7120(10) degrees and Z=8. In both complexes the copper atoms have square-planar environments bridged by two oxygen atoms from methoxide groups. Magnetic susceptibility measurements indicate a very strong antiferromagnetic coupling between the copper(II) ions in both complexes (2J<-1000 cm(-1)). Electronic Paramagnetic Resonance (EPR) spectra of the two complexes both in solid and in solution are silent. 13C NMR spectra of the complexes in solid state have been studied. The complexes have been evaluated as model systems for the catechol oxidase enzyme using 3,5-di-tert-butylcatechol as the test substrate. Complex 2 is slightly more active than complex 1.
Journal of Inorganic Biochemistry, 2006
A flavonol iron(III) complex, [Fe(flavonolato) 2 Cl(MeOH)], has been prepared. The compound has b... more A flavonol iron(III) complex, [Fe(flavonolato) 2 Cl(MeOH)], has been prepared. The compound has been characterized by X-ray crystallography, spectroscopy, magnetism and electronic paramagnetic resonance (EPR) at X-and Q-band. The geometrical environment around the metal is best described as rhombic distorted octahedral. This distortion has also been inferred from the magnetic measurements and from the EPR spectra at different temperatures, E/D(rhombicity parameter) % 0.06. The DNA cleavage activity of the iron(III) complex with and without ascorbate/hydrogen peroxide is reported. Mechanisms of the oxidative cleavage have been proposed when DNA strand scission is performed both with and without ascorbate/hydrogen peroxide activation.
Journal of Biological Inorganic Chemistry, 2003
Copper(II) ternary complexes based on the novel benzothiazole- N-sulfonamides, HL1 ( N-2-(4-methy... more Copper(II) ternary complexes based on the novel benzothiazole- N-sulfonamides, HL1 ( N-2-(4-methylbenzothiazole)benzenesulfonamide) and HL2 ( N-2-(6-nitrobenzothiazole)naphthalenesulfonamide) ligands, and pyridine have been synthesized and characterized. Complexes [Cu(L1)(2)(py)(2)] (1). and [Cu(L2)(2)(py)(2)] (2). were chemically characterized and their structures determined by means of single crystal X-ray analysis. In both compounds the Cu(II) ion is coordinated to four N atoms in a nearly square planar arrangement. The Cu-N bond distances are similar to those of Cu(2)Zn(2)SOD. The SOD mimetic activity of the complexes was determined both in vitro and in vivo. For determining the SOD-like activity of the complexes in vivo, we have developed a new method based on the complexes' protective effect on a delta sod1mutant of Saccharomyces cerevisiae against free radicals generated by hydrogen peroxide and menadione as well as free radicals produced in the cellular respiration process. The results have shown that complex 1 presents a protective action against oxidative stress induced by menadione or H(2)O(2) and that both complexes 1 and 2 protect against free radicals generated in cellular respiration.
Acta Crystallographica Section A Foundations and Advances, 2015
Computers and Electronics in Agriculture, 2014
ABSTRACT Currently, the process of accrediting a certain crop to become a Protected Designation o... more ABSTRACT Currently, the process of accrediting a certain crop to become a Protected Designation of Origin (PDO) valid one for the fabrication of Sidra de Asturias implies the visual inspection of the crop by technicians who ensure that there are only PDO valid varieties. It becomes then necessary a rapid, non-destructive, easy-to-use, cheap, trustable and efficient method to objectively classify the crop in order to detect possible frauds or human unintentional errors in the identification. Rapid methods for identification of different apple varieties based on Attenuated Total Reflectance (ATR)–Fourier Transform Infrared fingerprint spectroscopy assisted by Linear Discriminant Analysis (LDA) and by Artificial Neural Networks (ANN) have been developed. For each assayed variety, different sections of clean apple skins were selected and scanned from 600 cm�1 to 4000 cm�1. Apple data extracted from FTIR spectroscopy were gathered, analyzed and the final 372 reduced spectra were randomly distributed into training data sets (70%) and test data sets (30%). The classification results based on the LDA model gave a higher success rate (95.0%) than the ANN algorithm (85.5%) in the test data sets, although ANN presented a lower incorrect classification rate (1.9%) vs. LDA (5.0%). The ATR–FTIR technique coupled to chemometric approaches demonstrated to be useful, rapid, cheap and easy-to-use for identifying apple varieties. Success rate is better in LDA than in ANN, although ANN has a lower error rate because of its ability to detect ‘unclassifiable’ samples. These methods may be a helpful industrial approach to ensure the adequate selection of apple varieties to obtain a perfectly-balanced product under the PDO standards.
Acta Crystallographica Section A Foundations of Crystallography, 2009
Journal of Solid State Chemistry, 2000
Three non-isostructural metal(II) coordination polymers (metal=copper, cobalt, cadmium) were synt... more Three non-isostructural metal(II) coordination polymers (metal=copper, cobalt, cadmium) were synthesized under the same mild hydrothermal conditions (T=408K) by mixture of the corresponding metal acetate with 2-carboxyethylphosphonic acid and 1,10-phenanthroline (1:1:1 M ratio) and their structures were determined by single-crystal X-ray diffraction. Cu2(HO3PCH2CH2COO)2(C12H8N2)2(H2O)2 and Cd2(HO3PCH2CH2COO)2(C12H8N2)2 are triclinic (space group P-1) with a=7.908(5)Å, b=10.373(5)Å, c=11.515(5)Å, α=111.683(5)°, β=95.801(5)°, γ=110.212(5)° (T=120K), and a=8.162(5)Å, b=9.500(5)Å,
Journal of Solid State Chemistry, 2015
Organic Letters, 2007
The chemical synthesis and enzymatic desymmetrization of a panel of prochiral diamines have been ... more The chemical synthesis and enzymatic desymmetrization of a panel of prochiral diamines have been successfully described for the first time using lipases in organic solvents. A family of 2-aryl-1,3-propanediamines has been obtained with high enantiopurity and good yields in the PSL-catalyzed reaction using diallyl carbonate in 1,4-dioxane.
ChemCatChem, 2014
ABSTRACT Alcohol dehydrogenases (ADHs) were identified as suitable enzymes for the reduction of t... more ABSTRACT Alcohol dehydrogenases (ADHs) were identified as suitable enzymes for the reduction of the corresponding α,α-dihalogenated ketones, obtaining optically pure β,β-dichloro- or β,β-dibromohydrins with excellent conversions and enantiomeric excess. Among the different biocatalysts tested, ADHs from Rhodococcus ruber (ADH-A), Ralstonia sp. (RasADH), Lactobacillus brevis (LBADH), and PR2ADH proved to be the most efficient ones in terms of activity and stereoselectivity. In a further study, two racemic α-substituted ketones, namely α-bromo- α-chloro- and α-chloro-α-fluoroacetophenone were investigated to obtain one of the four possible diastereoisomers through a dynamic kinetic process. In the case of the brominated derivative, only the (1R)-enantiomer was obtained by using ADH-A, although with moderate diastereomeric excess (>99 % ee, 63 % de), whereas the fluorinated ketone exhibited a lower stereoselectivity (up to 45 % de).
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Zeitschrift für anorganische und allgemeine Chemie, 2003
ABSTRACT Copper(II) complexes of new N-benzothiazole sulfonamides (HL1= N-2-(benzothiazole)naphta... more ABSTRACT Copper(II) complexes of new N-benzothiazole sulfonamides (HL1= N-2-(benzothiazole)naphtalensulfonamide and HL2 = N-2-(6-chlorobenzothiazole)toluenesulfonamide) with ethylenediamine (en) and diethylenetriamine (dien) have been synthesized and characterised. The crystal structures of [Cu(dien)2](L1)2 (1) and [Cu(en)2(H2O)2](L2)2 (2) compounds have been determined. The metal centre adopts a “4+2” distorted octahedral environment in both complexes. Unusually, the sulfonamidate anions act as counterions. Spectroscopic properties are in good agreement with the crystal structures. The superoxide dismutase (SOD)-like activity of complex 2 has been tested.Kupfer(II)-Polyamin-Komplexe mit N-Benzothiazol-Sulfonamidaten als Gegenionen — Synthese, Kristallstrukturen und Eigenschaften von [Cu(dien)2](L1)2[HL1 = N-2-(Benzothiazol)naphthalinsulfonamid, dien = diethylentriamin] und [Cu(en)2(H2O)2](L2)2 [HL2 = N-2-(6-Chlorbenzothiazol)toluolsulfonamid, en = Ethylendiamin] — Superoxid-Dismutase-AktivitätKupfer(II)-Komplexe neuer N-Benzothiazol-Sulfonamide (HL1 = N-2-(Benzothiazol)naphthalinsulfonamid und HL2 = N-2-(6-Chlorbenzothiazoltoluolsulfonamid) mit Ethylendiamin (en) und Diethylentriamin (dien) wurden synthetisiert und charakterisiert. Die Kristallstrukturen von [Cu(dien)2](L1)2 (1) und [Cu(en)2(H2O)2](L2)2 (2) wurden ermittelt. Die Metallzentren weisen eine verzerrt oktaedrische „4+2”-Koordination auf. Ungewöhnlich ist die Funktion der Sulfonamidat-Anionen als Gegenionen. Die spektroskopischen Eigenschaften sind in guter Übereinstimmung mit den Kristallstrukturen. Die Superoxid-Dismutase-Aktivität (SOD) von Komplex 2 wurde ermittelt.
Tetrahedron: Asymmetry, 2006
An efficient chemoenzymatic route for the synthesis of optically active substituted indolines has... more An efficient chemoenzymatic route for the synthesis of optically active substituted indolines has been developed. Different lipases have been tested in the alkoxycarbonylation of these secondary amines, Candida antarctica lipase A (CAL-A) was found to be the best biocatalyst for 2-substituted-indolines, and C. antarctica lipase B (CAL-B) for 3-methylindoline. The combination of lipases with a variety of allyl carbonates and
Tetrahedron: Asymmetry, 2014
ABSTRACT Prop-2-en-1-yl[(1S,2R)-2-amino-1,2-bis(3-bromophenyl)ethyl]carbamateC18H18Br2N2O2Ee = 14... more ABSTRACT Prop-2-en-1-yl[(1S,2R)-2-amino-1,2-bis(3-bromophenyl)ethyl]carbamateC18H18Br2N2O2Ee = 14% (HPLC, Column Chiralcel OJ-H)[α]D20=+1.2 (c 0.5, EtOH)Source of chirality: Lipase-catalyzed desymmetrization with CAL-AAbsolute configuration: (1S,2R)
Tetrahedron, 2009
The chemical preparation and stereoselective enzymatic desymmetrization of a series of prochiral ... more The chemical preparation and stereoselective enzymatic desymmetrization of a series of prochiral 2-substituted-1,3-propanediamines have been carried out using Pseudomonas cepacia lipase as biocatalyst. Syntheses of novel optically active orthogonally protected di- or triamines have been achieved for the first time with different grade of enantiodiscrimination depending on the C-2 substitution of the propane-1,3-diamine fragment. Final monoselective deprotection reactions of (S)-3-allyl-2-tert-butyl-1-(9-fluorenylmethyl)propane-1,2,3-triyltriscarbamate
Zeitschrift für Kristallographie, 2003
A combination of X-ray powder diffraction and single crystal studies on azithomycin pseudopolymor... more A combination of X-ray powder diffraction and single crystal studies on azithomycin pseudopolymorphs give the precise solid state composition of all monohydrate pseudopolymorphs reported. According to the X-ray results the four monohydrates of azithromycin studied have the same crystallographic parameters. Furthermore, the analysis of the relative intensities from the powder patterns points to very similar chemical compositions and crystal structures. This result has been confirmed by the single crystal studies. The single crystal studies show that the solid state conformation of the azithromycin molecules is affected by the presence of solvents. The solvent methanol molecules were found disordered probably due to the existence of many positions where the hydrogen bonding is favoured and the large size of the available space to host the solvents.
Zeitschrift für Kristallographie, 2000
The structure of a new semihydrate solvated form of the antibiotic azithromycin is reported. The ... more The structure of a new semihydrate solvated form of the antibiotic azithromycin is reported. The new form was obtained by partial dehydration of the crystal of the monohydrate-i-PrOH, when the sample was left in laboratory conditions (295-298 K, 55-65% relative humidity) over a long period of time (about 40 months). The new semihydrate solvate form retains the crystalline structure of the monohydrate (unit cell parameters and space group) but shows changes in the position of the hydrogen atoms of some OH groups of the azithromycin molecules, leading to a new and different hydrogen bonding network. Moreover, in one of the two azithromycin molecules in the asymmetric unit (the one labelled as "b"), the dimethylamine group (in the desosamine sugar) shows a significant positional change. This fact provides information about the role of the solvent in the building of the solvated forms of the azithromycin drug, and allows the mobility of this group to be associated with an inversion operation and not a rotation. Scheme 1. Solvated forms of azithromycin.
Zeitschrift für Kristallographie, 2005
This paper describes the crystal structure of the azithromycin monohydrate pseudopolymorph (pseud... more This paper describes the crystal structure of the azithromycin monohydrate pseudopolymorph (pseudopolymorphic forms, different solvates of the same chemical compound, azithromycin in our case) crystallised from isopropanol, solved by X-ray single crystal, and called isopropanol clathrate monohydrate (Apotex, US 6,245,903). The powder diffraction patterns for this compound show a structure very similar to the azithromycin monohydrate crystallised from ethanol, called stable monohydrate (Biochemie, WO 0100640), and the X-ray single crystal confirms the fact that this new pseudopolymorph is isostructural to the previously reported, the referred stable monohydrate.
Journal of Inorganic Biochemistry, 2003
Two new mu-methoxo-bridged dinuclear copper(II) complexes with a N-substituted sulfonamide, [Cu(m... more Two new mu-methoxo-bridged dinuclear copper(II) complexes with a N-substituted sulfonamide, [Cu(mu-OMe)(L)(NH(3))](2) (1) and [Cu(mu-OMe)(L)(DMSO)](2) (2) [HL, N-2-(4-methylbenzothiazole)benzenesulfonamide], have been prepared and characterized by single-crystal X-ray difraction analyses. Compound 1 crystallizes in the monoclinic space group C(2)/c with a=22.0678(18), b=7.9134(7), c=21.1186(18)A, beta=113.788(4) degrees and Z=8. Compound 2 crystallizes in the monoclinic space group C(2)/c with a=18.0900(10), b=9.5720(10), c=24.2620(10) A, beta=98.7120(10) degrees and Z=8. In both complexes the copper atoms have square-planar environments bridged by two oxygen atoms from methoxide groups. Magnetic susceptibility measurements indicate a very strong antiferromagnetic coupling between the copper(II) ions in both complexes (2J<-1000 cm(-1)). Electronic Paramagnetic Resonance (EPR) spectra of the two complexes both in solid and in solution are silent. 13C NMR spectra of the complexes in solid state have been studied. The complexes have been evaluated as model systems for the catechol oxidase enzyme using 3,5-di-tert-butylcatechol as the test substrate. Complex 2 is slightly more active than complex 1.
Journal of Inorganic Biochemistry, 2006
A flavonol iron(III) complex, [Fe(flavonolato) 2 Cl(MeOH)], has been prepared. The compound has b... more A flavonol iron(III) complex, [Fe(flavonolato) 2 Cl(MeOH)], has been prepared. The compound has been characterized by X-ray crystallography, spectroscopy, magnetism and electronic paramagnetic resonance (EPR) at X-and Q-band. The geometrical environment around the metal is best described as rhombic distorted octahedral. This distortion has also been inferred from the magnetic measurements and from the EPR spectra at different temperatures, E/D(rhombicity parameter) % 0.06. The DNA cleavage activity of the iron(III) complex with and without ascorbate/hydrogen peroxide is reported. Mechanisms of the oxidative cleavage have been proposed when DNA strand scission is performed both with and without ascorbate/hydrogen peroxide activation.
Journal of Biological Inorganic Chemistry, 2003
Copper(II) ternary complexes based on the novel benzothiazole- N-sulfonamides, HL1 ( N-2-(4-methy... more Copper(II) ternary complexes based on the novel benzothiazole- N-sulfonamides, HL1 ( N-2-(4-methylbenzothiazole)benzenesulfonamide) and HL2 ( N-2-(6-nitrobenzothiazole)naphthalenesulfonamide) ligands, and pyridine have been synthesized and characterized. Complexes [Cu(L1)(2)(py)(2)] (1). and [Cu(L2)(2)(py)(2)] (2). were chemically characterized and their structures determined by means of single crystal X-ray analysis. In both compounds the Cu(II) ion is coordinated to four N atoms in a nearly square planar arrangement. The Cu-N bond distances are similar to those of Cu(2)Zn(2)SOD. The SOD mimetic activity of the complexes was determined both in vitro and in vivo. For determining the SOD-like activity of the complexes in vivo, we have developed a new method based on the complexes' protective effect on a delta sod1mutant of Saccharomyces cerevisiae against free radicals generated by hydrogen peroxide and menadione as well as free radicals produced in the cellular respiration process. The results have shown that complex 1 presents a protective action against oxidative stress induced by menadione or H(2)O(2) and that both complexes 1 and 2 protect against free radicals generated in cellular respiration.