Structural Characterization of β-Glycolaldehyde Dimer

Structural characterization of the β-polymorph of glycolaldehyde dimer by powder X-ray diffraction, Raman and infrared spectroscopies is described. The previously described α-polymorph and the β-polymorph both crystallize in the monoclinic crystal system, space group P21/c, but with different cell parameters. There are no significant differences in the glycolaldehyde dimer molecular structure, the molecules in both polymorphs are trans-isomers with the hydroxyl groups in axial positions. The two polymorphs have a different arrangement of the glycolaldehyde dimer molecules. In the previously reported α-polymorph the molecules are arranged in hydrogen bonded layers parallel to (100) while in the β-polymorph the hydrogen bonded molecules are arranged in a three-dimensional network. Theoretically calculated Gibbs free energy as well as differential scanning calorimetry indicate β-polymorph to be the stable crystal phase of glycolaldehyde. This work is licensed under a Creative Commons Attribution 4.0 International License

Chemistry of 1,3-Dioxepins. XVI.1 The Synthesis, Characterization and Crystallographic Analysis of Some Arylsulphanyl-, Arylsulphinyl-, Arylsulphonyl- and Benzoyl- N-Substituted Derivatives of 1a,2,6,6a-Tetrahydro-1H,4H-[1,3]dioxepino[5,6-b]azirines

Chemo-selective synthesis and characterization of N-[(4-nitrophenyl)sulphanyl]- 2 and N-[(4- nitrophenyl)sulphinyl]- 3 N-[(4-aminophenyl)sulphonyl]- 5 and N-(4-aminobenzoyl)- 7 derivatives of 1a,2,6,6a-tetrahydro-1H,4H-[1,3]dioxepino[5,6-b]azirines, starting from 1a,2,6,6a-tetrahydro-1H,4H-[1,3]dioxepino[5,6-b]azirine (1), are described. Their solid state conformational behaviour based on crystallographic analysis shows that: (i) dioxepinoazirine moiety of 2, 5 and 7 adopts a boat-chair (BC) conformation, while dioxepinoaziridine moiety of 3 adopts a twistboat (TB) conformation; (ii) the substituent on aziridine nitrogen is always in trans and never in cis position in relation to the dioxepane ring; (iii) the orientation of sulphanyl-, sulphinylsulphonyl- and carbonyl- moiety in 2, 3, 5 and 7 are defined by torsion angles C1-S1-N1-C7 of 110.7(2)°, 82.6(2)°, 88.80(11)°and C1-C-N1-C7 of 64.9(5)°, respectively; (iv) Phenyl moiety of sulphinyl and sulphonyl derivatives, 3 and 5, is perpendicular to the S-N bond with the torsion angles N1-S1-C1-C2 of 67.9(3)° and –92.54(13)°, respectively, while that of sulphanyl- 2 and carbonyl- 7 derivatives is coplanar to S-N or C-N bonds with the torsion angles N1-S1-C1-C2 and N1-C-C1-C2 of 168.5(2)° and 170.9(4)°, respectively. Obtained data will serve for further investigation of steric and electronic properties of studied compounds aimed at designing antihyperglycaemically more potent analogues

Synthesis, Crystal and Molecular Structure of Novel Adamantyl Derivatives of N-Aryl Substituted 3-Hydroxy-2-methylpyridine-4-ones

Two novel potentially bioactive compounds, esters 2-methyl-1-phenylpyridine-4-one-3-yl adamantan-1-ylethanoate (1) and 1-(p-methoxyphenyl)-2-methylpyridine-4-one-3-yl adamantan-1-ylethanoate (2), were synthesized by esterification of adamantan-1-ylacetic acid with appropriate N-aryl substituted 3-hydroxypyridine-4-one derivatives. Both compounds are fully characterized using standard spectroscopic methods. Crystal and molecular structures of 1 and 2 were determined by the single crystal X-ray diffraction method. The crystal packing of both 1 and 2 shows separation of the hydrophobic and hydrophilic regions. The crystal structure of 1 is characterized by the two-dimensional hydrogen bonding layers parallel to (001). The crystal packing of 2 is characterized by hydrogen-bonded chains extended in the direction [010].(doi: 10.5562/cca2339

4-Acetamido-N-(λ5-triphenyl­phospho­ranyl­idene)benzene­sulfonamide

There are two independent mol­ecules per asymmetric unit of the title compound, C26H23N2O3PS. Their superposition shows that they differ in the conformation of the CH3CO– group and the benzene rings from the triphenyl­phospho­rane group. In the crystal structure, independent mol­ecules are inter­conected by strong N—H⋯O hydrogen bonds, forming infinite chains along the a axis

Structure of the T6 Human Nickel Insulin Derivative at 1.35 Å Resolution

This paper presents results of the structural investigation on the human insulin hexamer derivative stabilised by nickel coordination. Single crystals of the Ni-insulin derivative were prepared by the hanging drop vapour diffusion crystallisation method using metal-free insulin and nickel(II) acetate tetrahydrate. The low-temperature crystal structure was determined by the single crystal X-ray crystallographic method with data extending to 1.35 Å spacing. The investigated insulin derivative exhibits the T6 form of insulin and crystallizes in the trigonal system in space group R3, with the unit cell parameters a = b = 81.41 Å and c = 33.75 Å. There are two nickel atoms per insulin hexamer and both are octahedrally coordinated by three Nε2 atoms of three symmetry-related HisB10/HisD10 and three oxygen atoms of three symmetry-related water molecules

Ternary Coordination Compounds of Copper(II) with Glycine and 2,2\u27-bipyridine: Synthesis, Structural Characterization, Magnetic and Biological Properties

Three new coordination compounds of copper(II) with glycine (HGly) and 2,2\u27-bipyridine (bipy) were synthesized by solution-based and mechanochemical methods: [Cu(Gly)(H2O)(bipy)][Cu(Gly)(SO4)(bipy)]·6H2O (1a·6H2O), [Cu(Gly)(H2O)(bipy)]2SO4 (1b), [Cu(Gly)(H2O) (bipy)]2SO4·H2O (1b·H2O). The amount of water in the reaction mixture influenced the product of crystallization. All compounds were characterized by X-ray diffraction methods and form 1D infinite chains or 2D sheets of complex ions connected by π-interactions. Compounds 1a·6H2O and 1b were characterized by X-band electron spin resonance (ESR) spectroscopy and the values of g-tensors for Cu(II) ions were determined. Compounds 1a·6H2O and 1b showed pronounced antiproliferative activity toward a panel of six human cell lines. The most impared was HepG2 cell line at 10−5 mol dm−3 concentration (74.5 % reduction of cell growth) followed by moderate activity toward KATO III, Caco-2, MDA-MB-231, PANC-1 and MRC-5 cells at 10−4 mol dm−3 concentration of compounds 1a·6H2O and 1b. Generally, both compounds express similar antiproliferative effect on evaluated cells

Chemistry of 1,3-Dioxepins. XV.1 Syntheses and Structure of Nitroaryl Analogues of Antihyperglycaemic N-Sulphonyl-1a,2,6,6a-tetrahydro-1H,4H-[1,3]-dioxepino[5,6-b]azirines

Regio and stereocontrolled syntheses of novel nitrophenyl analogues of antihyperglycaemic N-sulphonyl-1a,2,6,6a-tetrahydro-1H,4H-[1,3]-dioxepino[5,6-b]azirines: N-nitrobenzenesulphonylcyclohepta[6]azirine 6, N-nitrobenzenesulphonyldioxepinoazirines 7-10, N-nitro-benzoyldioxepinoazirine 11 and N-nitrobenzyldioxepinoazirine 12, starting from cycloheptene (2), trans-6-acetylamino-2-isopropyl-5-chloro-1,3-dioxepane (13) and 5,6-epoxy-1,3-dioxepane (14), are described. Their crystallographic data show that: (a) boat-chair (BC) conformation of dioxepinoazirine and cyclohepta[b]azirine moieties dominates; (b) the substituent on aziridine nitrogen is always in trans and never in cis position in relation to the cycloheptane or dioxepane ring; (c) the sulphonyl group of sulphonylaziridines 6 and 8-10 adopts only one of the two possible conformations in relation to the aziridine ring, with torsion angles C1-S-N-C7 of ≅ 80° (corresponding angle O1-S-N-LP ≅ 180°, LP = lone pair) named by us conformation BC*; (d) orientation of the analogous carbonyl group of 11 and methylene group of 12 is defined by torsion angles C1-C0-N1-C7 of -78.3 (9)° and -93.9 (5)° respectively; (e) nitrogen atom in all studied N-sulphonyl-, acyl- and alkyl- aziridines is sp3 hybridised, in contrast to other sulphonamides where sp2 hybridisation is predominant; (f) nitrogen atom in alkylaziridine 12 is more pyramidal in relation to N-sulphonyl and N-acyl derivatives, and according to torsion angles 05-N2-C4-C5, the nitro group in all studied compounds is approximately coplanar to the phenyl ring plane. Obtained data will serve for further investigation of steric and electronic properties of studied compounds aimed at designing more antihyperglycaemically potent analogues

An Efficient Synthesis of Novel Adamantane β-Amino Acid: 2-(Adamant-2-yl)-3-aminopropanoic Acid

Novel adamantane-containing β-amino acid, 2-(adamant-2-yl)-3-aminopropanoic acid, interesting from the aspect of medicinal chemistry, was prepared and characterized. It was synthesized in a sequence of three steps with very good overall yield. In the first step ethyl adamant-2-ylidenecyanoacetate was prepared and its crystal structure was determined. Reduction of this unsaturated cyanoacetate by catalytic hydrogenation gave the ethyl ester of the desired amino acid. 2-(Adamant-2-yl)-3-aminopropanoic acid was obtained following ester hydrolysis. (doi: 10.5562/cca2122