Ammonium hydrogen (RS)-[(5-methyl-2-oxo-1,3-oxazolidin-3-yl)meth­yl]phospho­nate

In the title compound, NH4 +·C5H9NO5P−, the five-membered methyl­oxazolidin-2-one unit is disordered over two positions, the major component having a site occupancy of 0.832 (9). A three-dimensional network of O—H⋯O and N—H⋯O hydrogen bonds stabilizes the crystal structure

Betti bases from 4-(3-pyridazo)-1-naphthol: synthesis, coordination behaviour and unusual substitution reactions

A series of Betti bases from 4‐(3‐pyridyl)azo‐1‐naphthol dye, possessing flexible methylene or more constrained aryl‐methyne spaced NH‐containing side‐chains, were obtained and characterized. It was shown by NMR spectroscopy that the ligands exist in keto form. The products’ structure was confirmed by single crystal XRD of a selected sample. A study on the coordination ability of the ligands with silver(I) was performed, leading to an unexpected substitution reaction

(4-Carbamoylphenyl)boronic acid

In the title compound, C7H8BNO3, the molecule lies on an inversion center leading to a statistical disorder of the B(OH)2 and CONH2 groups. In the crystal structure, molecules are linked by N—H...O and O—H...O hydrogen bonds, forming sheets parallel to the bc plane. The B(OH)2 and CONH2 groups are twisted out of the mean plane of the benzene ring by 23.9 (5) and 24.6 (6)°, respectively

(R)-Methyl {[(2-carboxybicyclo[2.2.2]octan-1-yl)ammonio]methyl}phosphonate dichloromethane 0.25-solvate

The carboxylic acid molecule of the title compound, C11H20NO5P·0.25CH2Cl2, exists as a zwitterion with the H atom of the phosphonate group being transferred to the imine N atom. In the asymmetric unit, there are two crystallographically independent acid molecules adopting the same absolute configuration and differing slightly in their geometrical parameters. In each molecule, the imino and carboxyl groups are connected via an intramolecular N—H...O hydrogen bond. Intermolecular O—H...O and N—H...O hydrogen bonds induce the formation of layers parallel to the ab plane. The dichloromethane solvent molecule, with a site occupancy of 0.5, is located between the layers

3-[2-(5-tert-Butyl-1,2-oxazol-3-yl)hydrazinylidene]chroman-2,4-dione

In the title compound, C16H15N3O4, the dihedral angle between the chromane and isoxazole rings [r.m.s. deviations = 0.042 and 0.007 Å, respectively] is 20.33 (12)°. The molecular geometry is stabilized by an intramolecular N—H...O hydrogen bond. In the crystal, N—H...O hydrogen bonds generate chains along the c-axis direction. The crystal studied was a non-morohedral twin

3-Carboxyphenylboronic acid–theophylline (1/1)

The title two-component molecular crystal [systematic name: 3-(dihydroxyboranyl)benzoic acid–1,3-dimethyl-7H-purine-2,6-dione (1/1)], C7H7BO4·C7H8N4O2, comprises theophylline and 3-carboxyphenylboronic acid molecules in a 1:1 molar ratio. In the crystal, molecules are self-assembled by O—H...O and N—H...N hydrogen bonds, generating layers parallel to (-209). The layers are stacked through π–π [centroid–centroid distance = 3.546 (2) Å] and C—H...π interactions

Polydentate <i>N</i>,<i>O</i>-Ligands Possessing Unsymmetrical Urea Fragments Attached to a <i>p</i>-Cresol Scaffold

In this study, three series of polydentate N,O-ligands possessing unsymmetrical urea fragments attached to a p-cresol scaffold are obtained, namely mono- and bi-substituted open-chain aromatics, synthesised using a common experiment, as well as fused aryloxazinones. Separate protocols for the preparation of each series are developed. It is found that in the case of open-chain compounds, the reaction output is strongly dependent on both bis-amine and carbamoyl chloride substituents, while oxazinones can be effectively obtained via a common protocol. The products are characterized via 1D and 2D NMR spectra in solution and using single-crystal XRD. A preliminary study on the coordination abilities of the products performed via ITC shows that there are no substantial interactions in the pH range of 5.0–8.5 in general

Structural Characterization of Alzheimer DNA Promoter Sequences from the Amyloid Precursor Gene in the Presence of Thioflavin T and Analogs

Understanding DNA&ndash;ligand binding interactions requires ligand screening, crystallization, and structure determination. In order to obtain insights into the amyloid peptide precursor (APP) gene&ndash;Thioflavin T (ThT) interaction, single crystals of two DNA sequences 5&prime;-GCCCACCACGGC-3&prime; (PDB 8ASK) and d(CCGGGGTACCCCGG)2 (PDB 8ASH) were grown in the presence of ThT or its analogue 2-((4-(dimethylamino)benzylidene)amino)-3,6-dimethylbenzo[d]thiazol-3-ium iodide (XRB). Both structures were solved by molecular replacement. In the case of 8ASK, the space group was H3 with unit cell dimensions of a = b = 64.49 &Aring;, c = 46.19 &Aring;. Phases were obtained using a model generated by X3DNA. The novel 12-base-pair B-DNA structure did not have extra density for the ThT ligand. The 14-base-pair A-DNA structure with bound ThT analog XRB was isomorphous with previously the obtained apo-DNA structure 5WV7 (space group was P41212 with unit cell dimensions a = b = 41.76 &Aring;, c = 88.96 &Aring;). Binding of XRB to DNA slightly changes the DNA&rsquo;s buckle parameters at the CpG regions. Comparison of the two conformations of the XRB molecule: alone and bound to DNA indicates that the binding results from the freedom of rotation of the two aromatic rings