A new supramolecular assembly obtained by reaction between thiosaccharin and hexamethylenediamine

The crystal structure of hexamethylenediammonium bis(thiosaccharinate) dihydrate, [H3N-(CH2)6-NH3](tsac) 2 · 2 H2O (tsac = C7H4NO 2S2, the anion of thiosaccharin), was determined by single-crystal X-ray diffraction. It crystallizes in the monoclinic space group P21/a with Z = 4. The thiosaccharinate moiety is planar and shows small but significant modifications in the bonding of the thioamide functional group as compared with the protonated neutral molecule. The ionic crystal is further stabilized by an extensive H-bonding network, which links the anions and cations into an infinite three-dimensional supramolecular assembly. The FTIR spectrum of the compound is briefly discussed in comparison with those of the neutral constituent molecules.Centro de Química InorgánicaInstituto de Física La Plat

Structural and Vibrational Properties and NMR Characterization of (2’-furyl)-Imidazole Compounds

The furylimidazoles compounds have a great importance in biochemistry and pharmacology because many of them present interesting properties. They are also found in artificial compounds, such as agrochemicals, pharmaceuticals, dyes, plastics, solvents, photographic chemicals, electronics, corrosion inhibitors, preservatives, and polymers. They can be used in synthetic organic chemistry as building blocks, due to their presence as key structural units in many natural products and in important pharmaceuticals. For example, the nature of the N- atoms in the imidazole molecule makes possible an extraordinary variety of reactions and this is the main reason for the great biological importance of the amino acid, histidine.Fil: Ledesma, Ana Estela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Instituto de Química del Noroeste. Grupo Vinculado Unse-inquinoa; ArgentinaFil: Zinczuk, Juan. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; ArgentinaFil: López González, Juan J.. Universidad de Jaén; EspañaFil: Brandan, Silvia Antonia. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química Inorgánica. Cátedra de Química General.; Argentin

A new supramolecular assembly obtained by reaction between thiosaccharin and hexamethylenediamine

The crystal structure of hexamethylenediammonium bis(thiosaccharinate) dihydrate, [H3N-(CH2)6-NH3](tsac) 2 · 2 H2O (tsac = C7H4NO 2S2, the anion of thiosaccharin), was determined by single-crystal X-ray diffraction. It crystallizes in the monoclinic space group P21/a with Z = 4. The thiosaccharinate moiety is planar and shows small but significant modifications in the bonding of the thioamide functional group as compared with the protonated neutral molecule. The ionic crystal is further stabilized by an extensive H-bonding network, which links the anions and cations into an infinite three-dimensional supramolecular assembly. The FTIR spectrum of the compound is briefly discussed in comparison with those of the neutral constituent molecules.Centro de Química InorgánicaInstituto de Física La Plat

(-)-Isosantonic acid: Alteration of the hydrogen-bonding mode by configurational inversion at a single centre in a γ,ε- diketocarboxylic acid

The title diketo acid, (1R,3aS,6aS,7R,9S)-(-)-α,3a,7-trimethyl-5,8- dioxo-1,4-ethanoperhydropentalene-1-acetic acid (C15H 20O4), is shown to aggregate in the crystal structure as acid-to-ketone hydrogen-bonding catemers, whose chains follow 21 screw axes from each carboxyl to a ketone in a neighbouring molecule [O⋯O = 2.7472(13) and O⋯H - O = 172.7(17)°]. Two parallel counterdirectional screw-related single-strand hydrogen-bonding chains pass through the cell in the a direction. Six intermolecular C - H⋯O=C close contacts are found. Comparisons are drawn with a diastereomer having the opposite configuration at the methylated chiral centre adjacent to the carboxyl group.Fil: Zinczuk, Juan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; ArgentinaFil: Ruveda, Edmundo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; ArgentinaFil: Lalancette, Roger A.. Rutgers University; Estados UnidosFil: Thompson, Hugh W.. Rutgers University; Estados Unido

A new supramolecular assembly obtained by reaction between thiosaccharin and hexamethylenediamine

The crystal structure of hexamethylenediammonium bis(thiosaccharinate) dihydrate, [H3N-(CH2)6-NH3](tsac) 2 · 2 H2O (tsac = C7H4NO 2S2, the anion of thiosaccharin), was determined by single-crystal X-ray diffraction. It crystallizes in the monoclinic space group P21/a with Z = 4. The thiosaccharinate moiety is planar and shows small but significant modifications in the bonding of the thioamide functional group as compared with the protonated neutral molecule. The ionic crystal is further stabilized by an extensive H-bonding network, which links the anions and cations into an infinite three-dimensional supramolecular assembly. The FTIR spectrum of the compound is briefly discussed in comparison with those of the neutral constituent molecules.Centro de Química InorgánicaInstituto de Física La Plat

A New Supramolecular Assembly Obtained by Reaction Between Thiosaccharin and Pyridine

The crystal structure of pyridinium thiosaccharinate thiosaccharin, [HNC5H5]+ [(tsac)(Htsac)]− (Htsac = C7H5NO2S2, the thiosaccharin molecule), was determined by single-crystal X-ray diffraction. Both, the thiosaccharinate anion, the corresponding neutral molecule and the pyridinium cation are nearly planar and arranged in the solid state in an almost parallel fashion, hence giving rise to a layered supramolecular structure. The anion shows small but significant modifications in the bonding of the thioamide group as compared with the neutral molecule. The crystal is further stabilized by an extensive H-bonding network. The FTIR spectrum of the compound is briefly commented.Publicado on line en 2014.Centro de Química Inorgánic

Three new thiosaccharin derivatives generated in a complex reaction system

The reaction between thiosaccharin and ethylamine showed to be relatively complex. The main product of this reaction is 3-ethylamino-1,2-benzisothiazole 1,1-dioxide (1), which could be clearly identified by NMR and IR spectroscopies. Ethylammonium thiosaccharinate (2) and 3-vinylamino-1,2-benzisothiazole 1,1 dioxide (3) were generated as minor by products during this reaction and their structures were determined by X-ray diffraction methods. The (2) salt crystallizes in the monoclinic P21/c space group with a=13.1367(5), b=9.9721(4), c=8.8217(3) Å, β=99.125(4)°, and Z=4, whereas compound (3) belongs to the P21/m space group with a=7.1572(5), b=7.0242(7), c=9.5503(8) Å, β=95.008(7)°, and Z=2.La reacción entre tiosacarina y etilamina muestra ser relativamente compleja. El producto principal de esta reacción es el 1,1 dióxido de 3-etilamino-1,2 benzisotiazol (1), que pudo ser claramente identificado por espectroscopia NMR e IR. El tiosacarinato de etilamonio (2) y el 1,1 dióxido de 3-vinilamino-1,2 benzisotiazol (3) se generan como subproductos minoritarios de la reacción y sus estructuras pudieron ser determinadas por métodos de difracción de rayos X. La sal (2) cristaliza en el sistema monoclínico, grupo espacial P21/c con a=13.1367(5), b=9.9721(4), c=8.8217(3) Å, β=99.125(4)°, y Z=4, mientras que el compuesto (3) pertenece al grupo espacial P21/m con a=7.1572(5), b=7.0242(7), c=9.5503(8) Å, β=95.008(7)°, y Z=2.Centro de Química InorgánicaInstituto de Física La Plat

Regioselective N- or O-tritylation of 2(1H)-pyridone - (triphenylmethyl)pyridones as tritylation agents

Die Tritylierung von 2(1H)-Pyridon (1) mit Chlortriphenylmethan (4) in Acetonitril führt über das Lithiumsalz 1' ausschließlich zu N-Trityl-2(1H)-pyridon (3a), über das Natriumsalz 1'' dagegen ausschließlich zum 2-Pyridyl-trityl-ether (3b). In Gegenwart von Lewis-Säuren lagert 3b in das thermodynamisch stabilere 3a um. 3a und b erwiesen sich für Alkohole als sehr gute und selektiv reagierende Tritylierungsagentien in neutralem Medium. Durch Protonensäuren, insbesondere Trifluoressigsäure, wird die Tritylierungsgeschwindigkeit deutlich erhöht.Tritylation of 2(1H)-pyridone (1) with triphenylmethyl chloride (4) in acetonitrile leads exclusively to N-trityl-2(1H)-pyridone (3a) via the lithium salt 1', whereas 2-pyridyl trityl ether (3b) is the only product from the reaction with the sodium salt 1''. In the presence of Lewis acids 3b rearranges to 3a, which shows the higher thermodynamic stability. 3a and b react with alcohols as excellent and selective tritylation agents in neutral medium. The tritylation rate increases in the presence of protonic acids, especially trifluoroacetic acid

On the interaction of vanadium species with the monoisoamyl ester of meso-2,3-dimercaptosuccinic acid

The interaction of the VO2+ cation with the monoisoamyl ester of meso-2,3-dimercaptosuccinic acid (MiADMSA) was investigated by electron absorption spectroscopy in aqueous solutions at different pH values. The spectral behavior, complemented with a spectrophotometric titration, shows the generation of a [VO(MiADMSA)2]⁴⁻ complex in which the oxocation interacts with two pairs of deprotonated –SH groups of the ester. Besides, MiADMSA rapidly reduces VO₃− to VO²⁺, which might be chelated by an excess of the ester, and also produces relatively rapid reduction of V₂O₅ suspensions at pH = 6.5. The results of this study suggest that MiADMSA might be a potentially useful detoxification agent for vanadium.Centro de Química Inorgánic