Search

Propane-1,3-diaminium squarate dihydrate, C3H12N22+·C4O42−·2H2O, results from the proton-transfer reaction of propane-1,3-di amine with squaric acid and subsequent crystallization from aqueous medium. The title compound crystallizes in the tetragonal crystal system (space group P4bm) with Z = 2. The squarate dianion belongs to the point group D4h and contains a crystallographic fourfold axis. The propane-1,3-diaminium dication exhibits a C2v-symmetric all-anti conformation and resides on a special position with mm2 site symmetry. The orientation of the propane-1,3-diaminium ions makes the crystal structure polar in the c-axis direction. The solid-state supramolecular structure features a triperiodic network of strong hydrogen bonds of the N—H⋯O and O—H⋯O types. [ABSTRACT FROM AUTHOR]

In view of the rise of drug-resistant tuberculosis and difficult-to-treat related diseases caused by non-tuberculous mycobacteria, there is an urgent need for antimycobacterial drug discovery. Nα-aroyl-N-aryl-phenylalanine amides (AAPs) have been identified as antimycobacterial agents and are subject to lead optimization. The aim of the present study is to evaluate the impact of N-aryl ortho cyano substitution in a lead compound on the crystal and molecular structure and its in vitro activity against Mycobacterium abscessus. The title AAP can be conveniently synthesized from N-Boc-protected d-phenylalanine in two amide coupling steps using a previously established racemization-free method. Two polymorphic forms in the solid-state are described, as discovered by X-ray and electron diffraction. The introduction of a cyano group in the ortho position of the AAP N-aryl ring, however, leads to loss of in vitro activity against M. abscessus subsp. abscessus. [ABSTRACT FROM AUTHOR]

The title compound, 3‐[(benzo‐1,3‐dioxol‐5‐yl)amino]‐4‐methoxycyclobut‐3‐ene‐1,2‐dione, C12H9NO5 (3), is a precursor to an antimycobacterial squaramide. Block‐shaped crystals of a monoclinic form (3‐I, space group P21/c, Z = 8, Z′ = 2) and needle‐shaped crystals of a triclinic form (3‐II, space group P‐1, Z = 4, Z′ = 2) were found to crystallize concomitantly. In both crystal forms, R22(10) dimers assemble through N—H...O=C hydrogen bonds. These dimers are formed from crystallographically unique molecules in 3‐I, but exhibit crystallographic Ci symmetry in 3‐II. Twinning by pseudomerohedry was encountered in the crystals of 3‐II. The conformations of 3 in the solid forms 3‐I and 3‐II are different from one another but are similar for the unique molecules in each polymorph. Density functional theory (DFT) calculations on the free molecule of 3 indicate that a nearly planar conformation is preferred. [ABSTRACT FROM AUTHOR]

4-(4-nitrophenyl)thiomorpholine, the title compound, has been used as a precursor for the corresponding 4-thiomorpholinoaniline, which is a useful building block in medicinal chemistry. The crystal and molecular structures of the title compound, however, have not been described thus far. We synthesized the title compound by means of a nucleophilic aromatic substitution reaction of 4-fluoronitrobenzene and thiomorpholine and structurally characterized it by X-ray crystallography, DFT calculations, and Hirshfeld surface analysis. In the crystal, the molecule exhibits an approximately CS-symmetric structure, with the nitrogen-bound 4-nitrophenyl group in a quasi axial position on the six-membered thiomorpholine ring in a low-energy chair conformation. The solid-state structure of the title compound is markedly different from that of its morpholine analogue. This can be ascribed to the formation of centrosymmetric dimers through intermolecular C–H···O weak hydrogen bonds involving the methylene groups adjacent to the sulfur atom and face-to-face aromatic stacking. [ABSTRACT FROM AUTHOR]

The crystal structure of 1,2,3,4-tetra-hydro-isoquinolin-2-ium (2 S ,3 S )-3-carb-oxy-2,3-di-hydroxy-propano-ate monohydrate, C 9 H 12 N + ·C 4 H 5 O 6 - ·H 2 O, at 115 K shows ortho-rhom-bic symmetry (space group P 2 1 2 1 2 1 ). The hydrogen tartrate anions and solvent water mol-ecules form an intricate diperiodic O-H⋯O hydrogen-bond network parallel to (001). The tetra-hydro-isoquinolinium cations are tethered to the anionic hydrogen-bonded layers through N-H⋯O hydrogen bonds. The crystal packing in the third direction is achieved through van der Waals contacts between the hydro-carbon tails of the tetra-hydro-isoquinolinium cations, resulting in hydro-phobic and hydro-philic regions in the crystal structure., (© Seidel and Kolev 2024.)