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1.
Giovanna Gasparri Fava Marisa Belicchi Ferrari Giovanni Casiraghi Gloria Rassu Pietro Spanu 《Journal of chemical crystallography》1991,21(5):629-633
The crystal structure of the title lactone, C20H30O9, a potential precursor of uncommon 11-carbon sugar derivatives, has been determined by single-crystal diffraction methods. The compound crystallizes in the orthorhombic space groupP212121 witha=15.581(3),b=14.047(2),c=9.888(2) Å, andZ=4. The structure was solved by direct methods and refined by full-matrix least-squares toR=0.054. The absolute configuration of the seven stereogenic carbon atoms was deduced as 4R, 5R, 6R, 7R, 8S, 9R, 10R, being (R)-(+)-glyceraldehyde its progenitor. An intramolecular O-HO hydrogen bond is present. Weak interaction C-HO links the molecules in sheets parallel to the (100) plane. 相似文献
2.
Giovanna Gasparri Fava Marisa Ferrari Belicchi Daniele Belletti Giovanni Casiraghi Gloria Rassu 《Journal of chemical crystallography》1991,21(3):261-264
The crystal structure of the title lactone, C13H18O7, has been determined by single crystal diffraction methods. The compound crystallizes in the monoclinic space groupP21 witha=13.231(2),b=10.248(2),c=5.348(1) Å,=96.66(2)°, andZ=2. A total of 1055 reflection intensities were recorded on a Siemens AED single-crystal diffractometer (CuK radiation) at room temperature. The structure was solved by direct methods and electron density calculations. Full-matrix least-squares refinement gaveR=0.055 for 946 unique reflections above 2(I). The absolute configuration of the six chiral carbon atoms was deduced as 4S, 5R, 6R, 7S, 9R, 10R (crystallographic numbering corresponds to C-6, 5, 4, 3, 2, 1 in the title compound). An intermolecular O-HO hydrogen bond joins the molecules in chains which run along the twofold screw axis. 相似文献
3.
G. Pelosi M. Belicchi Ferrari M. C. Rodríguez‐Argüelles S. Mosquera‐Vzquez J. Sanmartín 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(6):m241-m242
The title compound, Na+·C9H7N4O5S−·2H2O, presents a Z configuration around the imine C=N bond and an E configuration around the C(O)NH2 group, stabilized by two intramolecular hydrogen bonds. The packing is governed by ionic interactions between the Na+ cation and the surrounding O atoms. The ionic unit, Na+ and 2‐oxo‐3‐semicarbazono‐2,3‐dihydro‐1H‐indole‐5‐sulfonate, forms layers extending in the bc plane. The layers are connected by hydrogen bonds involving the water molecules. 相似文献
4.
Giovanna Gasparri Fava Marisa Belicchi Ferrari Giorgio Pelosi Franca Zanardi Giovanni Casiraghi Gloria Rassu 《Journal of chemical crystallography》1996,26(7):509-513
The structure of 2,3-dideoxy-4-thio-d-arabino-heptonic acid 1,4-lactone has been determined by X-ray diffraction. Crystals of the compound are orthorhombic, space groupP212121, with cell dimensionsa=11.555(5),b=10.451(5),c=9.604(5) Å, andZ=4. The diffraction experiment has allowed to assign the absolute configuration (4R, 5R, 6R) to the chiral centers of the molecule. 相似文献
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6.
Marisa Belicchi Ferrari Giovanna Gasparri Fava Giorgio Pelosi Gianfranco Denti 《Journal of chemical crystallography》1997,27(4):257-261
[3,6-bis(2-pyridyl)pyridazine-N 1,N2]bis(triphenylphosphine) copper(I) hexafluorophosphate crystallizes in space group $P\bar 1$ with cell dimensionaa=14.050(2),b=11.941(2),c=15.200(2) Å, α=71.28(1), β=67.02(1), and γ=84.78(2)o. In the title compound, the mononuclear cation consists of a tetrahedral copper(I) center involving two nitrogen donors of the 3,6-bis(2-pyridyl)pyridazine (dppn) and two P atoms of the triphenylphosphine molecules. In the dppn ligand the two non-coordinating N atoms (one from pyridine and one from pyridazine) are mutallytrans. 相似文献
7.
G. Pelosi C. Pelizzi M. Belicchi Ferrari M. C. Rodríguez‐Argüelles C. Vieito J. Sanmartín 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(10):o589-o592
The two title semicarbazones, namely 2,3‐dihydro‐1H‐indole‐2,3‐dione 3‐semicarbazone, C9H8N4O2, (I), and 1‐methyl‐2,3‐dihydro‐1H‐indole‐2,3‐dione 3‐semicarbazone, C10H10N4O2, (II), show the same configuration, viz. Z around the imine C=N bond and E around the C(O)—NH2 bond, stabilized by two intramolecular hydrogen bonds. The presence of a methyl group on the isatin N atom determines the difference in the packing; in (I), the molecules are linked into chains which lie in the crystallographic (102) plane and run perpendicular to the b axis, while in (II), the molecules are arranged to form helices running parallel to a crystallographic screw axis in the a direction. 相似文献
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9.
Franca Bigi Giovanni Casiraghi Giuseppe Casnati Giovanni Sartori Paolo Soncini Giovanna Gasparri Fava Marisa Ferrari Belicchi 《Tetrahedron letters》1985,26(16):2021-2024
Treatment of phenols with optically active (+)- and (?)-menthyl pyruvate assisted by Al(III)- or Ti(IV)-based promoters leads to the formation of -hydroxyatrolactic esters of (2R)- and (2S)-configuration. The use of suitable menthol-based promoters augments markedly (up to 96% d.e.) the intrinsic stereochemical bias of the chiral pyruvate. 相似文献
10.
Belicchi Marisa Ferrari Gasparri Giovanna Fava Pelizzi Corrado Tarasconi Pieralberto 《Transition Metal Chemistry》1985,10(8):295-299
Summary The reactions of Cu(NO3)2 · 3 H2O with 2- (2-thienyl)-1-(2-thienylmethyl)benzimidazole (L) and of CuCl2 · 2H2O with 2-(2-thienyl)benzimidazole (L) have been carried out. The crystal structure of two isolated complexes,(1) and(2), have been determined by single-crystal x-ray diffraction methods. Crystals of(1) are monoclinic, space groupP21
/c, witha=9.884(4),b=9.892(4),c=18.732(8) Å, =114.89(2)°,Z=2;R=0.068 for 1909 observed reflections. Crystals of (2) are orthorhombic, space groupPbcn, witha=14.835(1),b=8.193(1),c=20.493(1) Å,Z=4;R=0.086 for 415 observed reflections. In the complex (1) the copper co-ordination is tetragonal (compressed octahedral) and involves a nitrogen atom of the organic ligand [Cu-N 1.970(6) Å] and two oxygen atoms of the nitrate group [Cu-O 2.318(7) and 2.246(9) Å] which appears to coordinate nearly symmetrically to the metal; however it has unusually large thermal motion which suggests a fluxional behaviour. In the complex (2) the co-ordination is square planar and involves an imidazole nitrogen [Cu-N 1.95(3) Å] and a chlorine atom [Cu-Cl 2.27(1) Å]. A long interaction Cu-S=3.37(2) Å completes the co-ordination polyhedron to a very elongated distorted tetragonal bipyramid. In both compounds a thiophene ring is disordered. 相似文献