Synthesis, Secondary Structure, and Anion Binding of Acyclic Carbohydrate-Derived Oligo(amide-triazole)s

A family of linear, carbohydrate-derived oligo(amide-triazole)s has been designed and synthesized. These molecules possess a regular distribution of triazole rings (from one to four) linking the carbohydrate units to give dimer to pentamer derivatives. Their binding to halide anions was qualitatively analyzed by means of NMR spectroscopy and mass spectrometry. All the compounds were able to bind chloride anions, with a stoichiometry that depended on the chain length. The dimer and trimer gave 2:1 host/chloride ratio, while the tetramer and pentamer gave 1:1 complexes. The secondary structure of the oligo(amide-triazole)s was studied using NMR spectroscopy and circular dichroism. These studies showed that the larger host molecules (tetramer and pentamer) adopted a stabilized U-turn and were able to bind just one chloride anion. Only the pentamer displayed a helical conformation, which was slightly distorted in the presence of chloride salts. Interestingly, chloride binding involves not only the triazole-CH but also H atoms from the carbohydrate moieties. These compounds could be applied for chloride sensing by ESI-MS.Fil: Fidalgo, Daniela Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Monge, Maria Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; ArgentinaFil: Varela, Oscar Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Kolender, Adriana Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; Argentin

Polysaccharides from Nothogenia fastigiata y Georgiella confluens (Rhodophyta) : new analytical methods for algal polysaccharides

Este trabajo de Tesis versa sobre cuatro aspectos principales: l- Estudio de los polisacáridos del alga roja Nolhogenia jásligiala (Galaxauraceae, Nemaliales) y evaluación de su actividad antiviral. Comprende un sistema de D-mananos con uniones α-(l—>3), sulfatados en las posiciones 2 y 6, y con ramificaciones simples de D-xilosa enlazada β-(l—>2).Los xilomananos contenían mayoritariamente cationes de calcio y magnesio, que estaban involucrados en la formación de complejos entre los polisacáridos del sistema mediante interacciones cooperativas carbohidrato-carbohidrato dependientes de calcio. La fracción F6' fue la más activa frente a varias cepas de HSV tipos 1 y 2, dos de ellas resistentes a aciclovir. Por otra parte, no presentó actividad anticoagulante, lo cual constituye una ventaja para su aplicación potencial como agente antiviral en formulaciones de aplicación local. 2- Aplicación de espectrometría de masa UV-MALDI-TOF, para determinar los pesos moleculares y sus funciones de distribución, sobre xilomananos sulfatados y xilanos neutros de N.fastigiala. 3- Análisis estructural de los polisacáridos de Georgiella confluens (Ceramiaceae, Ceramiales). Los resultados indicaron la presencia de una cadena central de agarano altamente metilado con un esquema de sustitución inusual en galactanos de algas rojas: sulfatación en C-3 de unidades de α-L-galactosa y ramificaciones simples de xilosa en la posición 4 de β-D-galactosa. 4- Desarrollo de un método de desulfatación para polisacáridos sulfatados empleando clorotrimetilsilano. Permitió completar el análisis estructural de los xilogalactanos de G. confluens. También se encontraron las mejores condiciones para la desulfatación de carragenano kappa comercial, a fin de probar su eficacia en un polisacárido con máximo contenido de unidades de 3,6-anhidrogalactosa. El estudio por experimentos RMN mono- y bidimensionales de carragenano beta -obtenido por desulfatación de carragenano kappa permitió la asignación completa de su espectro protónico.This Thesis comprises four major sections: l- Analysis of the polysaccharides from the red seaweed Nolhogenia filsligiala (Galaxauraceae, Nernaliales) and evaluation of their antiviral activities. The sulfated polysaccharides extracted from this seaweed comprise a family of α-(l → 3)-linked D-mannans, 2- and 6-sulfated and having single stubs of β-(1 → 2)-linked D-xylose. The high content of calcium and magnesium cations revealed the complexation -mediated by calcium-dependent, cooperative carbohydrate-carbohydrate interactions- of polysaccharides belonging to the system. Fraction F6' proved to be the most active against several HSV strains, two of them resistant to acyclovír. At the same time, F6' did not exhibit anticoagulant properties, making it interesting for potential use as an antiviral agent in local formulations. 2- Application of UV-MALDI-TOF mass spectrometry to xylans and sulfated xylomannans in order to determine their molecular weights and distribution functions. 3- Structural analysis of the polysaccharides from Georgiella confluens (Ceramiaceae, Ceramiales). The results indicated the presence of a highly methylated agaran backbone with an unusual substitution pattern for red seaweed galactans: sulfation mainly at the 3-position of the α-L-galactose units and the presence of xylose single stubs at the 4-position of the β-D-galactose residues. 4- Development of a desulfation method for sulfated polysaccharides using chlorotrimethylsilane. Its application made possible the structural elucidation of the sulfated xylogalactans from G. confluens. Besides, in order to determine its efficiency in a polysaccharide with the highest 3,6-anhydrogalactose content, the best conditions for desulfation of commercial kappa carrageenan were tested. Complete assignment of the 1H NMR rcsonances of beta carrageenan -obtained by desulfation of kappa carrageenan- was achieved by means of mono- and bidimensional NMR techniques.Fil:Kolender, Adriana Andrea. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Synthesis and characterization of poly-O-methyl-[n]-polyurethane from a d-glucamine-based monomer

Aminoalditol 1-amino-1-deoxy-d-sorbitol (1) was readily converted into 2,3,4,5-tetra-O-methyl derivative 5, a key precursor of a sugar-based [n]-polyurethane. For the polymerization, the free amino or primary hydroxyl groups of 5 were selectively activated and employed as starting monomers in two alternative procedures. Thus, the amino function of 5 was converted into the isocyanate derivative by treatment with di-tert-butyltricarbonate, and polymerized in situ in the presence of Zr(IV) acetylacetonate. The resulting poly(1-amino-1-deoxy-2,3,4,5-tetra-O-methyl-d-sorbitol)urethane (8) had a moderate molecular weight and showed the presence of urea units. The alternative synthesis of 8 involved the activation of the free hydroxyl group of 5 as the corresponding phenylcarbonate. The polymerization of this α-amino-ω- phenylcarbonate alditol monomer does not require a metal catalyst. The resulting material exhibited an improved molecular weight and higher purity than that obtained via the isocyanate. [n]-polyurethane 8 was highly soluble in water as well as in common organic solvents (chloroform, acetone, ethyl acetate, etc) and was obtained as an amorphous material which was characterized thermally and spectroscopically.Fil: Kolender, Adriana Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Arce, Silvina M.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Varela, Oscar Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; Argentin

Stereoregular poly-O-methyl [m,n]-polyurethanes derived from D-mannitol

Novel linear carbohydrate-derived [m,n]-polyurethanes are successfully prepared using d-mannitol as renewable and low cost starting material. The key comonomer, 1,6-di-O-phenylcarbonyl-2,3,4,5-tetra-O-methyl-d-mannitol is polymerized with a diamine synthesized from d-mannitol or with alkylenediamines. These polymerization reactions afford, respectively, a [6,6]-polyurethane entirely based on a carbohydrate derivative or [m,n]-polyurethanes constituted by a poly-O-methyl substituted unit alternating with a polymethylene chain. All these polymers are stereoregular, as result of the C2 axis of symmetry of mannitol. The optically active polyurethanes are characterized by standard methods (FTIR, RMN, GPC, TGA, and DSC). Thus, GPC analysis reveals weight-average molecular weights between 18,000 and 25,000 Da. Thermal studies (DSC) indicate that the polymers obtained are amorphous materials with Tg values dependent on the structure and chain length of the diamine constituent.Fil: Fidalgo, Daniela Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Kolender, Adriana Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Varela, Oscar Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono; Argentin

Galactose-derived poly(amide-triazole)s: Degradation, deprotection and derivatization studies

A family of stereoregular poly(amide-triazole)s derived from D-galactose was obtained following several principles of Green Chemistry, namely bio-based starting materials, high yields, benign reaction conditions, energy efficiency, catalysis, atom economy, and chemical degradation. The monomer precursors, the α-azido-ω-N-alkynylamide derivatives, were prepared from D-galactose, which was oxidized to D-galactono-1,4-lactone and the secondary hydroxyl groups were protected as isopropylidene acetals. The AB-type azide-alkyne click polymerization led to poly(amide-triazole)s. The Cu(I)-catalyzed polymerization led regioselectively to 1,4-disubstituted triazole ring, and hence to a stereoregular polymer. In contrast, the thermal polymerization produced also 1,5-disubstituted triazole units. The stereoregular polymer underwent acid-promoted chemical degradation, and the degradation products were identified. Moreover, selective removal of the acid labile acetonide moieties led to a partially protected poly(amide-triazole). This polymer was further modified using the “grafting from” approach. Thus, the ROP of caprolactone initiated from the free hydroxyl groups of the polymer led to a linear poly(amide-triazole) grafted with short biodegradable polycaprolactone side-chains. On the other hand, complete HO-deprotection of the monomer gave, after click polymerization, the fully unprotected polymer. The protected poly(amide-triazole)s showed a higher thermal stability compared to the hydroxylated derivatives, which could undergo dehydration processes at lower temperatures. Similarly, the partially protected polymer gave a lower Tg value, in agreement with an increasing degree of structural disorder (non-stereoregular materials) and/or lower molecular weight.Fil: Rivas, Maria Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Varela, Oscar Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Kolender, Adriana Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; Argentin

Poly(amide-triazole)s obtained by regioselective, microwave-assisted click polymerization of bio-based monomers

The Cu(I)-catalyzed, microwave-assisted click polymerization of bio-based -azide--alkyne monomers afforded, with high regioselectivity, stereoregular poly(amide-triazole)s. The monomers were prepared starting from d-glucono-1,5-lactone as a renewable resource. The synthetic route involves the selective protection of this sugar lactone with formaldehyde to give a gluconic acid derivative, which was subjected to amidation of the carboxylic acid function with alkynylamines (2-propynyl, 3-butynyl, and 4-pentynylamines) and substitution of the primary hydroxyl group by azide. The regioselective click polymerization of these AB-type alkyne/azide monomers led to a series of linear biosourced poly(amide-triazole)s containing mostly (>95%) 1,4-disubstituted triazole linkages. In contrast, the thermal, metal-free click polymerization led to random distribution of 1,4- and 1,5-disubstituted triazoles in the polymer backbone. The length of the methylene chain linked to the amide of the monomer and the cycloaddition regioselectivity strongly affected the properties of the materials, mainly the Tg values, which were unexpectedly high.Fil: Fidalgo, Daniela Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Kolender, Adriana Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Varela, Oscar Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; Argentin

Synthesis of ω-amino-α-phenylcarbonate alkanes and their polymerization to [n]-polyurethanes

Aliphatic [n]-polyurethanes have recently been synthesized from ω-isocyanato-α-alkanols or, more traditionally, by cationic ring-opening polymerization of cyclourethanes or by the Bu2Sn(OMe)2-promoted polycondensation of ω-hydroxy-α-O- phenylurethane alkanes. For the latter procedures, the conditions employed do not seem to be suitable for highly functionalized monomers. In contrast, the polymerization of ω-amino-α-phenylcarbonate alkanes is expected to occur under milder conditions. ω-Amino-α-phenylcarbonate alkanes have been synthesized from 6-aminohexanol (1) and 3-aminopropanol (6). The procedure involves the N-Boc protection of the amino group, followed by activation of the alcohol. Removal of the N-Boc affords the corresponding ω-amino-1-O-phenyloxycarbonyloxyalkane hydrochlorides. Other oligomeric comonomers between 1 and 6 have been prepared. The polymerization of these precursors takes place in the absence of metal catalysts to afford the corresponding linear and regioregular [n]-polyurethanes. The procedure described is useful for the preparation of stable ω-amino-α-phenylcarbonate alkane derivatives, which possess varied chain lengths between the terminal functions. These monomers yield [n]-polyurethanes having various structures starting from just two aminoalkanols. The polyurethanes were obtained in high yields, with reasonable molecular weight and polydispersity values, and they were characterized spectroscopically and thermally. These studies reveal constitutionally uniform structures that are free of carbonate or urea linkages.Fil: Arce, Silvina M.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Kolender, Adriana Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Varela, Oscar Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; Argentin

Optimization and Validation of a GC–FID Method for Quantitative Determination of 1,3-Propanediol in Bacterial Culture Aqueous Supernatants Containing Glycerol

Abstract: 1,3-Propanediol (1,3-PDO) is an important chemical widely used in polymer production. This compound has been traditionally obtained by chemical synthesis, but it can also be obtained from bacterial fermentation using glycerol as renewable carbon source. Since 1,3-PDO and glycerol have a similar chromatographic behavior, it is not easy to determine both compounds efficiently in short runs. In this work, we optimized a rapid and simple capillary GC–FID method for the determination of 1,3-PDO and glycerol directly in bacterial culture supernatants. Good peak shapes and high resolution were obtained with no significant tailing. The method was validated in terms of specificity, linearity, precision, accuracy, limit of detection, limit of quantitation, robustness and stability according to USP and ICH guidelines. The method can be applied for the determination of 1,3-PDO and glycerol in different media in less than 5 min with high precision, reproducibility and selectivity. No time-consuming extraction or concentration steps and no significant matrix effects make this method outstanding for glycols determination. Graphical Abstract: [Figure not available: see fulltext.].Fil: Egoburo, Diego Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Díaz Peña, Rocío. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Kolender, Adriana Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; ArgentinaFil: Pettinari, María Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentin

Polymeric Biocomposites from Renewable and Sustainable Natural Resources

The use of polymeric composite materials from renewable biomass hasacquired great importance in different and varied fields. Moreover, its applicationin the biomedical applications has found a fast development in recent years. In thiscontext, this chapter is focused on the use of biocomposites in tissue engineeringand analytical applications. The studied materials include polysaccharides such aschitosan, cellulose, and alginate, as well as polyhydroxyalcanoates as matrixes, andfillers like nanoparticles, carbon nanotubes or polymers, among other combinations.Fil: Fidalgo, Daniela Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; ArgentinaFil: Contin, Mario Daniel. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Química Analítica y Fisicoquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Kolender, Adriana Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: D'accorso, Norma Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; Argentin

Vinal gum, a galactomannan from Prosopis ruscifolia seeds: physicochemical characterization

Physico-chemical and rheological characterization of the gum extracted from the endosperm of vinal(Prosopis ruscifolia) seeds was performed. The CG-MS analysis revealed that vinal gum is a galactomannanwith a mannose/galactose ratio of 1.6, with traces of arabinose and glucose residues. Thestructure was further confirmed by 13C NMR which showed several similarities between vinal gum andguar gum spectra. The viscosity molecular weight was 1.43 ± 0.04$106 Da (obtained from Huggins plot)and the average number molecular weight was 0.7$105 Da. Shear continuous rheology studies showed ashear thinning behavior at concentrations higher than 0.04% (w/v) of vinal gum and an apparent viscosityslightly lower than that of guar gum at the same concentration. Mechanical spectra revealed that vinalgum has a typical macromolecular solution behavior with the moduli crossing point that characterizedsemi-diluted (0.16e0.3% w/v) gum solutions. The present work provides structural, physicochemical andrheological information of a new galactomannan from an abundant and available non-traditional source,being a starting point for food, pharmaceutical or other industrial potential applications of vinal gum.Fil: Busch, Verónica María. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Industrias; ArgentinaFil: Kolender, Adriana Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Santagapita, Patricio Roman. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Industrias; ArgentinaFil: Buera, Maria del Pilar. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Industrias; Argentin