Search

Cocrystals of 2,7-dihydroxynaphthalene (DHN, or naphthalene-2,7-diol) with isoniazid (pyridine-4-carbohydrazide) (INH), denoted DHN–INH [C10H8O2·C6H7N3O, (I)], and piracetam [2-(2-oxopyrrolidin-1-yl)acetamide] (PIR), denoted DHN–PIR [C10H8O2·C6H10N2O2, (II)], were obtained by the solvent-assisted grinding method and characterized by IR spectroscopy, powder X-ray diffraction and single-crystal X-ray diffraction. Cocrystal (I) crystallized in the triclinic space group P\overline{1} and showed a 2:2 stoichiometry. DHN and INH molecules are connected by O—H...N(pyridine) and O—H...N(hydrazide) hydrogen bonds. Cocrystal (II) crystallized in the space group Pca21 with a 1:1 stoichiometry. DHN and PIR molecules are connected by O—H...O=C hydrogen bonds. The supramolecular architecture of cocrystal (I) showed interlinked supramolecular tapes; meanwhile, in cocrystal (II), interlinked supramolecular sheets were observed.

Sulfamethazine [N 1-(4,6-dimethylpyrimidin-2-yl)sulfanilamide] is an antimicrobial drug that possesses functional groups capable of acting as hydrogen-bond donors and acceptors, which make it a suitable supramolecular building block for the formation of cocrystals and salts. We report here the crystal structure and solid-state characterization of the 1:1 salt piperidinium sulfamethazinate (PPD+·SUL−, C5H12N+·C12H13N4O2S−) (I). The salt was obtained by the solvent-assisted grinding method and was characterized by IR spectroscopy, powder X-ray diffraction, solid-state 13C NMR spectroscopy and thermal analysis [differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA)]. Salt I crystallized in the monoclinic space group P21/n and showed a 1:1 stoichiometry revealing proton transfer from SUL to PPD to form salt I. The PPD+ and SUL− ions are connected by N—H+...O and N—H+...N interactions. The self-assembly of SUL− anions displays the amine–sulfa C(8) motif. The supramolecular architecture of salt I revealed the formation of interconnected supramolecular sheets.

Pharmaceutical cocrystallization offers the possibility to modify the physicochemical and biopharmaceutical properties of active pharmaceutical ingredients. The mechanochemical synthesis and spectroscopic characterization of the catechol-theophylline (CAT-TEO) cocrystal is reported. The cocrystal was prepared by the solvent-assisted grinding method. The ATR-IR spectroscopy study allowed to determine the formation of the cocrystal because the O-H and C=O stretching bands in the CAT-TEO cocrystal were shifted with respect to the starting materials, suggesting the formation of the C=O···H-O hydrogen bond interaction. Infrared spectroscopy also allowed to discard hydration of the cocrystal, and polymorphic transitions of the starting products as a consequence of the mechanochemical grinding. The X-ray powder diffraction and thermal studies confirmed the formation of a new solid phase. In the solid state 13C NMR spectra of the cocrystal, the signals were shifted with respect to the starting products. The 13C NMR chemical shifts of the CAT-TEO cocrystal were simulated by using the gauge including the atomic orbital (GIAO) method. These results showed a good correlation between the experimental and calculated 13C NMR results. Theoretical calculations and natural bonding orbital analysis (NBO) at a B3LYP/6-31G(d,p) level of theory were performed to obtain structural information of the cocrystal.

Pharmaceutical cocrystals are crystalline solids formed by an active pharmaceutical ingredient and a cocrystal former. The cocrystals 2,6-diaminopyridine (DAP)–piracetam [PIR; systematic name: 2-(2-oxopyrrolidin-1-yl)acetamide] (1/1), C5H7N3·C6H10N2O2, (I), and 2,6-diaminopyridine–theophylline (TEO; systematic name: 1,3-dimethyl-7H-purine-2,6-dione) (1/1), C5H7N3·C7H8N4O2, (II), were prepared by the solvent-assisted grinding method and were characterized by IR spectroscopy and powder X-ray diffraction. Cocrystal (I) crystallized in the orthorhombic space group Pbca and showed a 1:1 stoichiometry. The DAP and PIR molecules are linked by an N—H...O hydrogen-bond interaction. Self-assembly of PIR molecules forms a sheet of C(4) and C(7) chains. Cocrystal (II) crystallized in the monoclinic P21/c space group and also showed a 1:1 stoichiometry. The DAP and TEO molecules are connected by N—H...N and N—H...O hydrogen bonds, forming an R 2 2(9) heterosynthon. A bidimensional supramolecular array is formed by interlinked DAP–TEO tetramers, producing a two-dimensional sheet.

The mechanochemically induced complexation between diethyl N,N′-1,3-phenyldioxalamate tweezers and resorcinol, orcinol, 4,6-di-tert-butyl-1,3-benzenediol, and 4-hexyl-1,3-benzenediol is described. IR-spectroscopy, X-ray powder diffraction, 13C CPMAS, and single X-ray diffraction allowed establishing the structures of the complexes as hydrogen-bonded heterodimers and heterotetramers. Complexation occurs through O–H···O═C hydrogen-bonding interactions with the participation of phenolic OH and amide carbonyl groups. The initial conformation and steric factors coming from the 1,3-benzenediols exert a strong influence on the final structure of the complex formed. Complexation twists both oxalyl arms by 180°, strengthens the intramolecular (amide)CO···H(Csp2)···OC(amide) three-centered hydrogen bond, and moves apart the oxalyl arms to allow the accommodation of the 1,3-benzenediol inside the cavity. The supramolecular architectures of the complexes in 1-D are directed by R12(6), R22(10), and R12(6) adjacent hyd...

The synthesis, density functional theory (DFT) molecular structure and Fourier transform infrared spectroscopy (FTIR) molecular recognition study of diethyl phenylenebis(methylene) dicarbamates with 1,2- and 1,3-benzenediols is described. The formation of the complexes was confirmed by the shift of the O-H stretching bands in the IR spectra of the complexes compared with the IR spectra of the noncomplexed benzenediols.

Las tioureas, son compuestos resultantes de sustituir el átomo de oxígeno de la urea (NH2CONH2) por un átomo de azufre (NH2CSNH2). Actualmente se ha visto que las tioureas presentan diversas actividades biológicas, dentro de las que se encuentra la antimicrobiana. En el presente estudio se evaluó la actividad antibacteriana mediante acoplamiento molecular entre la enzima DNA girasa (receptor) y las tioureas (R, R)-N,N´-bis(1 ciclohexiletil)tiourea (CYTU1) y (R,R)-N,N´-bis(1-feniletil)tiourea (CYTU2) como ligando en busca del posible mecanismo de acción de estos compuestos, los resultados muestran que existe interacción entre la enzima y ambas tioureas en el sitio activo. Por otro lado, también se evaluó la actividad antibacteriana frente a cepas de Sthapylococcus aureus, Escherichia coli y Pseudomonas fluorescens, mediante el método de microdilución en caldo con la adición de bromuro de 3-(4,5-dimetil-2-tiazolil)-2,5-difeniltetrazolium (MTT), como parte del ensayo de viabilidad, mostrando una disminución de la misma sólo contra las bacterias gram negativas, siendo la tiourea CYTU2 la que mostró mejor actividad antibacteriana. Molecular docking and antibacterial activity thioureas (R,R)-N,N´-bis(1-cyclohexyethyl)thiourea and (R,R)-N,N´-bis(1-phenylethyl)thiourea Abstract Thioureas are resultant compounds of substitute the oxygen atom from urea (NH2CONH2) for a sulfur atom (NH2CSNH2). There are evidential that show the biological activity of thioureas, within which are antibacterial activity. We studied the antibacterial activity of two thioureas (R,R)-N,N´-bis(1 cyclohexylethyl)thiourea (CYTU1) y (R,R)-N,N´-bis(1 phenylethyl)thiourea (CYTU2) in silico using Molecular Docking between the DNA gyrase enzyme (receptor) and the two thioureas (ligand). The results showed interaction between DNA girase and both thioureas on the pocket of the enzyme. By other hand, the biological activity was evaluated against the following bacterial strains: Sthapylococcus aureus, Escherichia coli and Pseudomonas fluorescens, using the microdilution method broth with 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT) as part of the viability assay, the results show decrease in viability only in gram-negative strains, being the thiourea CYTU2 the that exhibited a better antibacterial activity

In the title compound, C24H36N6O6·C2H6OS, the carbonyl groups are in an antiperiplanar conformation, with O=C—C=O torsion angles of 178.59 (15) and −172.08 (16)°. An intramolecular hydrogen-bonding pattern is depicted by four N—H...O interactions, which form two adjacentS(5)S(5) motifs, and an N—H...N interaction, which forms anS(6) ring motif. Intermolecular N—H...O hydrogen bonding and C—H...O soft interactions allow the formation of ameso-helix. The title compound is the first example of a helical 1,2-phenylenedioxalamide. The oxalamide traps one molecule of dimethyl sulfoxide through N—H...O hydrogen bonding. C—H...O soft interactions give rise to the two-dimensional structure.

Facultad de Ciencias Químicas

In the title compound, C(16)H(18)N(4)O(2), the two carbonyl groups are in an anti-periplanar conformation with an O=C-C=O torsion angle of 173.86 (17)°. In the crystal, a pair of inter-molecular N-H⋯O hydrogen bonds, forming an R(2) (2)(10) ring motif, connect the mol-ecules into an inversion dimer. The dimers are further linked by N-H⋯N and C-H⋯π inter-actions, forming a zigzag chain along the b axis.

In this contribution the supramolecular architecture of a series of six 1,3-phenyl-dioxalamic molecular clefts is described. The conformation was controlled by the use of Me and OMe group substitution in the phenyl spacer. The structural and conformational study was carried out by X-ray diffraction analysis, DFT calculations at PBEPBE 6-31+G (3df, 3pd) theory level and variable temperature 1H NMR in solution. The C2-Me group exerts a dual influence on the conformation adopting the endo(sc) or exo(ac) conformations in the oxalamic arms, meanwhile the C2-OMe group leads to the adoption of the exo(ap) conformation. DFT study results showed that the exo(ap)–exo(ap) conformation is more stable than the other conformations due to the conjugation that stabilizes the molecule and minimizes the conformational energy. Supramolecular arrays in oxalamate/oxalamide derivatives of 1,3-diaminobenzene, 2-methyl-benzene-1,3-diamine and 2,4,6-trimethyl-benzene-1,3-diamine are directed by self-complementary N–H⋯O hydrogen bonding interactions, whose organization in the crystal depends on the twist of the oxalamic arms, meanwhile in oxalamate/oxalamide derivatives of 5-tert-butyl-2,6-diamineanisol with an exo(ap)–exo(ap) conformation, the supramolecular arrays are directed by π-stacking, dipolar carbonyl–carbonyl interactions and C–H⋯O soft contacts. N1,N1′-(1,3-(2,4,6-Trimethyl)-phenyl)-bis-(N2-(2-(2-hydroxyethoxy)ethyl)oxalamide) adopts the form of a supramolecular meso-helix, which is the first example of helical 1,3-phenyl-dioxalamide.