Molecular structure and selective theophylline complexation by conformational change of diethyl N,N'-(1,3-phenylene)dicarbamate.

The receptor ability of diethyl N,N'-(1,3-phenylene)dicarbamate (1) to form host-guest complexes with theophylline (TEO) and caffeine (CAF) by mechanochemistry was evaluated. The formation of the 1-TEO complex (C12H16N2O4·C7H8N4O2) was preferred and involves the conformational change of one of the ethyl carbamate groups of 1 from the endo conformation to the exo conformation to allow the formation of intermolecular interactions. The formation of an N-H...O=C hydrogen bond between 1 and TEO triggers the conformational change of 1. CAF molecules are unable to form an N-H...O=C hydrogen bond with 1, making the conformational change and, therefore, the formation of the complex impossible. Conformational change and selective binding were monitored by IR spectroscopy, solid-state 13C nuclear magnetic resonance and single-crystal X-ray diffraction. The 1-TEO complex was characterized by IR spectroscopy, solid-state 13C nuclear magnetic resonance, powder X-ray diffraction and single-crystal X-ray diffraction.

Crystal structure and characterization of the sulfamethazine-piperidine salt.

Sulfamethazine [N1-(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.

Crystal structures of cocrystals of 2,7-dihydroxynaphthalene with isoniazid and piracetam.

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-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.

Crystal structure of pharmaceutical cocrystals of 2,6-diaminopyridine with piracetam and theophylline.

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 R22(9) heterosynthon. A bidimensional supramolecular array is formed by interlinked DAP-TEO tetramers, producing a two-dimensional sheet.

Los cocristales farmacéuticos: conceptos generales / Pharmaceutical Cocrystals: General concepts

Los cocristales farmacéuticos surgen como una posibilidad para mejorar las propiedades biofarmacéuticas y farmacotécnicas de un IFA (Ingrediente Farmacéutico Activo). Los cocristales farmacéuticos son sólidos cristalinos constituidos por un IFA y un formador, los cuales se encuentran en la misma celda cristalina. La búsqueda de nuevos cocristales farmacéuticos es competencia de la química supramolecular, ya que el IFA y el formador se mantienen juntos mediante interacciones no covalentes. Existen métodos en solución y en sólidos para la formación de cocristales. Además, este campo ofrece una posibilidad de desarrollo intelectual debido a la posibilidad de patentar los productos, considerando los parámetros regulatorios. Este trabajo presenta los principales conceptos que se consideran para el estudio de estos sólidos farmacéuticos

Pharmaceutical co-crystals emerge as a possibility to improve the biopharmaceutical properties and pharmacotechnical of an Active Pharmaceutical Ingredient (API). Theco-crystalsare crystalline solids composed of an API and a former, which are located in the same crystal cell. The search for new pharmaceutical co-crystals is the responsibility of supramolecular chemistry, since the formerand the API are held together by non-covalent interactions. Solution and solid state methods are employed for the formation of cocrystals. In addition, this field offers a possibility of intellectual development due to the patentability of products, without neglecting the regulatory aspects. This work presents the main concepts considered for the study of these pharmaceutical solids

Helical supramolecular assembly of N2,N2')bis[3-(morpholin-4-yl)propyl]-N1,N1'-(1,2-phenylene)dioxalamide dimethyl sulfoxide monosolvate.

In the title compound, C(24)H(36)N(6)O(6)·C(2)H(6)OS, 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 adjacent S(5)S(5) motifs, and an N-H...N interaction, which forms an S(6) ring motif. Intermolecular N-H...O hydrogen bonding and C-H...O soft interactions allow the formation of a meso-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.

N,N'-Bis(4-amino-benz-yl)oxalamide.

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.