Reyna Reyes-Martínez

Synthesis and in vitro trichomonicidal, giardicidal and amebicidal activity of N-acetamide(sulfonamide)-2-methyl-4-nitro-1H-imidazoles

Two new series of imidazole derivatives (acetamides: 1-8 and sulfonamides: 9-15) were synthesized using a short synthetic route. Compound 1 as well as the intermediate 16g were characterized by X-ray crystallography. Imidazole derivatives 1-15 were tested in vitro against three unicellular parasites (Giardia intestinalis, Trichomonas vaginalis and Entamoeba histolytica) in comparison with benznidazole (Bzn) and metronidazole. Compound 1 [N-benzyl-2-(2-methyl-4-nitro-1H-imidazol-1-yl)acetamide] was 2 times more active than Bzn against T. vaginalis and G. intestinalis and it was as active as Bzn against E. histolytica. Sulfonamides showed selective toxicity against E. histolytica over the other parasites. Toxicity assay showed that all compounds are non-cytotoxic against MDCK cell line. The results revealed that compounds 1-15 have antiparasitic bioactivity in the micromolar range against the parasites tested, and could be considered as benznidazole bioisosteres.

Diorganotin(IV) complexes with furan-2-carbohydrazone derivatives: synthesis, characterization, crystal structure and antibacterial activity

Four new diorganotin(IV) complexes, R2SnL (L = La: R = Me 1, Ph 2; L = Lb: R = Me 3, and Ph 4), have been synthesized by reaction of hydrazone ONO donors, 5-bromo-2-hydroxybenzaldehyde furan-2-carbohydrazone (H2La) and 2-hydroxynaphthaldehyde furan-2-carbohydrazone (H2Lb) with diorganotin(IV) dichloride in the presence of a base. The compounds have been investigated by elemental analysis and IR, 1H NMR, and 119Sn NMR spectroscopies. Spectroscopic studies show that the hydrazone is a tridentate dianionic ligand, coordinating via the imine nitrogen and phenolic and enolic oxygens. The structures of H2Lb and 3 have also been confirmed by X-ray crystallography. The results show that the structure of 3 is a distorted square pyramid with imine nitrogen in apical position. The in vitro antibacterial activities of ligands and complexes have been evaluated against gram-positive (Bacillus cereus and Staphylococcus aureus) and gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria. H2La and H2Lb show no activity but the diphenyltin(IV) complexes exhibit good activities towards two bacterial strains in comparison with standard bacterial drugs.

Comparative analysis of M–O, M–S and cation–π(arene) interactions in the alkali metal (Na+, K+, Rb+, Cs+) bis-dithiocarbamate salts of N,N′-dibenzyl-1,2-ethylenediamine

The alkali metal (Na+, K+, Rb+, Cs+) bis-dithiocarbamate (bis-dtc) salts of N,N′-dibenzyl-1,2-ethylenediamine have been prepared from the reaction of N,N′-dibenzyl-1,2-ethylenediamine with carbon disulfide in the presence of two equivalents of the corresponding alkali metal hydroxide. Additionally, the analogous triethylammonium derivative has been obtained. The resulting compounds have been analyzed as far as possible by elemental analysis, FAB+ mass spectrometry, IR, UV-Vis and NMR (1H, 13C) spectroscopy, and single-crystal X-ray diffraction, showing that the composition of the metal salts can be described by the general formula [{[(H2O)xM-µ-(H2O)yM(H2O)x][bis-dtc]}n] (1, M = Na+, x = 3, y = 2; 2, M = K+, x = 1, y = 2; 3, M = Rb+, x = 0, y = 1; 4, M = Cs+, x = 0, y = 1; 5, M = Et3HN+, x = 0, y = 0). The solid-state and solution studies showed that all alkali metal ions participate in the formation of M–O and cation-π(arene) interactions, while M–S interactions are only observed for the larger alkali metals K+, Rb+ and Cs+. As expected, within the alkali metal group there is a clear tendency for a decreasing number of M–O bonds in favor of M–S and cation–π(arene) interactions, however, only K+ forms a semi-sandwich type complex with η6-coordination.

A comparative study of the packing of two polymorphs of the nickel(II) pincer complex [2,6-bis(di-tert-butylphosphinoyl)-4-(3,5-dinitrobenzoyloxy)phenyl-κ(3)P,C(1),P']chloridonickel(II).

Pincer complexes can act as catalysts in organic transformations and have potential applications in materials, medicine and biology. They exhibit robust structures and high thermal stability attributed to the tridentate coordination of the pincer ligands and the strong σ metal-carbon bond. Nickel derivatives of these ligands have shown high catalytic activities in cross-coupling reactions and other industrially relevant transformations. This work reports the crystal structures of two polymorphs of the title Ni(II) POCOP pincer complex, [Ni(C29H41N2O8P2)Cl] or [NiCl{C6H2-4-[OCOC6H4-3,5-(NO2)2]-2,6-(OP(t)Bu2)2}]. Both pincer structures exhibit the Ni(II) atom in a distorted square-planar coordination geometry with the POCOP pincer ligand coordinated in a typical tridentate manner via the two P atoms and one arene C atom via a C-Ni σ bond, giving rise to two five-membered chelate rings. The coordination sphere of the Ni(II) centre is completed by a chloride ligand. The asymmetric units of both polymorphs consist of one molecule of the pincer complex. In the first polymorph, the arene rings are nearly coplanar, with a dihedral angle between the mean planes of 27.9 (1)°, while in the second polymorph, this angle is 82.64 (1)°, which shows that the arene rings are almost perpendicular to one another. The supramolecular structure is directed by the presence of weak C-H...O=X (X = C or N) interactions, forming two- and three-dimensional chain arrangements.

Sulfonate salts of the therapeutic agent dapsone: 4-[(4-aminophenyl)sulfonyl]anilinium benzenesulfonate monohydrate and 4-[(4-aminophenyl)sulfonyl]anilinium methanesulfonate monohydrate.

Dapsone, formerly used to treat leprosy, now has wider therapeutic applications. As is the case for many therapeutic agents, low aqueous solubility and high toxicity are the main problems associated with its use. Derivatization of its amino groups has been widely explored but shows no significant therapeutic improvements. Cocrystals have been prepared to understand not only its structural properties, but also its solubility and dissolution rate. Few salts of dapsone have been described. The title salts, C12H13N2O2S(+)·C6H5O3S(-)·H2O and C12H13N2O2S(+)·CH3SO3(-)·H2O, crystallize as hydrates and both compounds exhibit the same space group (monoclinic, P21/n). The asymmetric unit of each salt consists of a 4-[(4-aminophenyl)sulfonyl]anilinium monocation, the corresponding sulfonate anion and a water molecule. The cation, anion and water molecule form hydrogen-bonded networks through N-H...O=S, N-H...Owater and Owater-H...O=S hydrogen bonds. For both salts, the water molecules interact with one sulfonate anion and two anilinium cations. The benzenesulfonate salt forms a two-dimensional network, while the hydrogen bonding within the methanesulfonate salt results in a three-dimensional network.

Crystal structure of 1-meth-oxy-pyrene.

The title compound, C17H12O, crystallized with three independent molecules (A, B and C) in the asymmetric unit. In the crystal, the three independent molecules are linked by π–π interactions [centroid–centroid distances = 3.551 (3)–3.977 (2) Å], which lead to the formation of trimers. Between the trimers there are a number of C—H⋯π interactions generating a laminar arrangement parallel to (010). The methoxymethyl group in molecule A is disordered over two sets of sites, with an occupancy ratio of 0.56 (9):0.44 (9).

Di­chlorido­(4,4′-di-tert-butyl-2,2′-bi­pyridine-κ2N,N′)palladium(II) dimethyl sulfoxide monosolvate monohydrate

The title compound, [PdCl2(C18H24N2)]·(CH3)2SO·H2O, the PdII ion is in a distorted square-planar geometry. The Pd—N bond distances are 2.022 (2) and 2.027 (2) Å, the Pd—Cl bond distances are 2.2880 (7) and 2.2833 (7) Å, and the ligand bite angle is 80.07 (9)°. The dimethyl sulfoxide and water molecules form linear chains along [100] by O—H⋯O and O—H⋯S hydrogen bonds, generating eight- and 12-membered rings. C—H⋯Cl interactions link the chains, forming a three-dimensional arrangement. In addition, the 4,4-di-tert-butyl-2,2′-bipyridine ligand exhibits π–π stacking interactions [centroid–centroid distances = 3.8741 (15) and 3.8353 (15) Å]. The DMSO solvent is disordered and was refined with an occupancy ratio of 0.866 (3):0.134 (3).

cis-Bis(O-methyl­dithio­carbonato-κ2S,S′)bis­(tri­phenyl­phosphane-κP)ruthenium(II)

In the title compound, [Ru(CH3OCS2)2(C18H15P)2], the RuII atom is in a distorted octahedral coordination by two xanthate anions (CH3OCS2) and two triphenylphosphane (PPh3) ligands. Both bidentate xanthate ligands coordinate the RuII atom with two slightly different Ru—S bond lengths but with virtually equal bite angles [71.57 (4) and 71.58 (3)°]. The packing of the complexes is assured by C—H⋯O and C—H⋯π interactions.

N-Benzyl-2-hy­droxy­ethanaminium cyanurate

In the cation of the title compound C9H14ON+·C3H2O3N3 −, the benzylamine C—N bond subtends a dihedral angle of 78.3 (2)° with the phenyl ring. The cyanurate anion is in the usual keto-form and shows an r.m.s. deviation from planarity of 0.010 Å. In the crystal, the cyanurate anions form N—H⋯O hydrogen-bonded zigzag ribbons along [001]. These ribbons are crosslinked by the organocations via O—H⋯N and N—H⋯O hydrogen bonds, forming bilayers parallel to (010) which are held together along [010] by slipped π–π interactions between pairs of cyanurate anions [shortest contact distances C⋯C = 3.479 (2), O⋯N = 3.400 (2); centroid–centroid distance= 4.5946 (9) Å] and between cyanurate and phenyl rings [centroid–centroid distance = 3.7924 (12) Å, ring–ring angle = 11.99 (10)°].

A second monoclinic polymorph of {2,6-bis[(2,4,5-trifluoro­phen­yl)imino­meth­yl]pyridine-κ3N,N′,N′′}dichloridonickel(II)

The asymmetric unit of the title compound, [NiCl2(C19H9F6N3)], contains one half-molecule residing on a crystallographic twofold rotation axis. The title compound crystallizes in space group C2/c while the previously reported polymorph was reported in P21/c [Baldovino-Pantaleón et al. (2006 ▶). Adv. Synth. Catal. 348, 236–242]. The Ni2+ ion exhibits a pentacoordinate distorted trigonal–bipyramidal NiCl2N3 geometry, with two Cl atoms in the equatorial plane. In the crystal, molecules are linked by intermolecular C—F⋯π [F⋯centroid = 2.9676 (14) Å] interactions.