Notizen: Die Kristallstruktur des Mauritins-A / The Crystal Structure of Mauritine-A

1976 ◽  
Vol 31 (2) ◽  
pp. 279-280 ◽  
Author(s):  
A. Kibfel ◽  
G. Will ◽  
R. Tschesche ◽  
H. Wilhelm
Keyword(s):  
Crystal Structure ◽  
Amino Acids ◽  
Ring System ◽  
Membered Ring ◽  
Trans Configuration ◽  
X Ray Diffraction ◽  
Uv Spectrum ◽  
X Ray ◽  
Cyclopeptide Alkaloid ◽  
Hydroxy Proline

The constitution and conformation of the known cyclopeptide alkaloid mauritine-A were determined by X-ray diffraction methods. All amino acids belong to the L-series, 3-hydroxy proline has trans-configuration. As indicated by the UV-spectrum, the 14-membered ring system is considerably strained.

Synthesis, crystal structure and molecular conformation of (±)-1-oxoferruginol and (±)-shonanol

2004 ◽  
Vol 219 (10) ◽  
Author(s):  
Swastik Mondal ◽  
Monika Mukherjee ◽  
Arnab Roy ◽  
Debabrata Mukherjee
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Diffraction Data ◽  
Molecular Conformation ◽  
Membered Ring ◽  
Methyl Groups ◽  
Single Bond ◽  
X Ray Diffraction ◽  
X Ray ◽  
Chemical Structures

Abstract(±)-1-oxoferruginol and (±)-shonanol, two potential intermediates in the synthesis of tricyclic diterpenoid ferruginol, have been prepared and crystal structures of the compounds have been investigated using single-crystal X-ray diffraction data. The methyl groups of the isopropyl moiety in (±)-shonanol are disordered over two positions with occupation factors 0.65(1) and 0.35(1), respectively. Although the chemical structures of two compounds are very similar, a C—C single bond in the terminal six-membered ring of (±)-1-oxoferruginol is replaced by a C=C bond in (±)-shonanol, the quantitative isostructurality index calculations indicate that the structures are not isostructural. Intermolecular O—H…O hydrogen bonds between pairs of molecules in the compounds related by center of inversion lead to characteristic dimers forming R

The X-Ray Crystal Structure of 1,2-3,4-Di-O-isopropylidene-4-C-methylthiomethoxy-β-L-arabino-hexoseptanos-5-ulose

1990 ◽  
Vol 43 (12) ◽  
pp. 2083 ◽  
Author(s):  
DC Craig ◽  
VJ James ◽  
JD Stevens
Keyword(s):  
Crystal Structure ◽  
Title Compound ◽  
Membered Ring ◽  
Boat Conformation ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray

The crystal structure of the title compound (1) has been determined by X-ray diffraction. Crystals of (1) are orthorhombic, space group P21212 with a 11.425(1), b 24.916(1), c 5.8952(3)Ǻ, Z 4. Refinement on 1675 observed reflections measured with Cu Kα radiation converged at R 0.034. The seven- membered ring adopts a boat conformation in which the pseudo plane of symmetry passes through the ring oxygen.

Synthesis and Crystal Structure Determination of Cyclosporin H

2000 ◽  
Vol 65 (8) ◽  
pp. 1317-1328 ◽  
Author(s):  
Alexandr Jegorov ◽  
Ladislav Cvak ◽  
Aleš Husek ◽  
Petr Šimek ◽  
Anna Heydová ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Amino Acids ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Synthesis And Crystal Structure ◽  
X Ray ◽  
Acid Catalyzed ◽  
Products Of Reaction ◽  
Cyclosporin H

Acid-catalyzed degradation of cyclosporin A was studied in various solvents and products of reaction were monitored by HPLC. Identification of amino acids and their chirality were determined after hydrolysis and derivatization by GC-MS. Cyclosporin H was isolated as the principal product and its structure was determined by X-ray diffraction: Cyclosporin H- diethyl ether-water (1 : 0.5 : 1) crystallizes in the monoclinic space group I2 with a = 12.338(2) Å, b = 18.963(2) Å, c = 34.074(3) Å, β = 96.47(2)°, Z = 4, and V = 7 921.4(17) Å3.

Perfluorotetracyclobutacyclo-octatetraene; a planar eight-membered ring system; X-ray crystal structure

1981 ◽  
pp. 526 ◽  
Author(s):  
Frederick W. B. Einstein ◽  
Anthony C. Willis ◽  
William R. Cullen ◽  
Robert L. Soulen
Keyword(s):  
Crystal Structure ◽  
Ring System ◽  
Membered Ring ◽  
X Ray

Cobalt(III) Complexes of the 10-Membered Macrocycle 1,4,7-Triazacyclodecane. The Structure of trans-Bis(1,4,7-triazacyclodecane)cobalt(III) Perchlorate

1993 ◽  
Vol 46 (12) ◽  
pp. 1955 ◽  
Author(s):  
TW Hambley ◽  
TW Hambley ◽  
GH Searle ◽  
GH Searle
Keyword(s):  
Crystal Structure ◽  
Membered Ring ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bond Lengths

The crystal structure of trans-[Co( tacd )2](ClO4)3 has been determined by X-ray diffraction methods and refined to a residual of 0.054 for 2477 independent observed reflections. The crystals are monoclinic, P 21/c, a 18.627(2), b 9.3438(5), c 16.057(2)Ǻ, β 119.45(2)°. Two complex cations are located at centres of symmetry and the ligands adopt λ,δ,chair conformations. Bond lengths from cobalt to nitrogen atoms in the six- membered ring (average 1.995 Ǻ) are significantly longer than those only associated with five- membered rings (average 1.961 Ǻ).

Tetramethyld-η2-vinyldisiloxan(triphenylphosphan)platin(0) / Tetramethyldi-η2-vinyldisiloxane(triphenylphosphine)platinum(0)

1991 ◽  
Vol 46 (12) ◽  
pp. 1694-1698 ◽  
Author(s):  
Georg Beuter ◽  
Olga Heyke ◽  
Ingo-Peter Lorenz
Keyword(s):  
Crystal Structure ◽  
Chair Conformation ◽  
Ring System ◽  
Platinum Atom ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray

The reaction of (Ph3P)2PtC2H4 with the divinyldisiloxane (CH2=CHSiMe2)2O in toluene yields Pt{(η2-H2C=CHSiMe2)2O}PPh3, which has been characterized by IR, 1H, 13C, 31P NMR and MS spectra. The crystal structure was determined by X-ray diffraction: space group C2/c, Z = 16, a = 5534.2(9), b = 842.6(2), c = 2383.1(2) pm, β = 103.73(1)°, R/Rw = 0.047/0.052. It shows a three-coordinate platinum atom with one phosphine and one sym-tetramethyldivinyldisiloxane ligand acting as a chelating bidentate η/2-ligand to give a chair conformation of the six-membered PtC2Si2O-ring system.

Crystal structure of zerumbone [(E,E,E)-2,6,9,9-Tetramethylcycloundeca-2,6,10-trien-1-one]

1981 ◽  
Vol 34 (10) ◽  
pp. 2243 ◽  
Author(s):  
SR Hall ◽  
S Nimgirawath ◽  
CL Raston ◽  
A Sittatrakul ◽  
S Thadaniti ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Least Squares ◽  
Membered Ring ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Zingiber Zerumbet ◽  
Space Group ◽  
X Ray ◽  
Considerable Distortion

The crystal structure of zerumbone, C15H22O, extracted from the rhizomes of Zingiber zerumbet Smith, has been determined by single-crystal X-ray diffraction at 295(1) K and refined by least squares to a residual of 0.051 for 925 'observed' reflections. Crystals are monoclinic, space group P21/c, a 9.036(3), b 9.712(5), c 15.643(6) �, β 97.19(3)�, Z = 4. Although the molecule has no chiral centre, the presence of the three trans double bonds confers considerable distortion and rigidity on the eleven-membered ring and renders the whole molecule chiral and potentially resolvable.

ChemInform Abstract: PERFLUOROTETRACYCLOBUTACYCLOOCTATETRAENE; A PLANAR EIGHT-MEMBERED RING SYSTEM; X-RAY CRYSTAL STRUCTURE

1981 ◽  
Vol 12 (40) ◽  
Author(s):  
F. W. B. EINSTEIN ◽  
A. C. WILLIS ◽  
W. R. CULLEN ◽  
R. L. SOULEN
Keyword(s):  
Crystal Structure ◽  
Ring System ◽  
Membered Ring ◽  
X Ray

scholarly journals Dibrom(dimethylamino)alan und Diiod(dimethylamino)alan. Darstellung und Kristallstruktur / Dibromo(dimethylamino)alane and Diiodo(dimethylamino)alane. Preparation and Crystal Structure

1978 ◽  
Vol 33 (1) ◽  
pp. 43-46 ◽  
Author(s):  
Aftabuddin Ahmed ◽  
Wolfgang Schwarz ◽  
Heinz Hess
Keyword(s):  
Crystal Structure ◽  
Membered Ring ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bond Lengths

Abstract The title compounds were prepared by reaction of dimethylaminoalane with mercury - (II) dibromide and diiodide, respectively, and investigated by X-ray diffraction. Both compounds build structures isotype with that of dichloro(dimethylamino)alane. The molecules exist as dimers with a planar four-membered ring of alternating aluminium and nitrogen atoms. These atoms are four-coordinated. The following bond lengths are found: Al-N 1.94 and 1.95 Å, Al-Br 2.26 Å, Al-I 2.49 Å, N-C 1.50 and 1.55 Å.

scholarly journals Crystal structure and absolute configuration of (3aS,4S,5R,7aR)-2,2,7-trimethyl-3a,4,5,7a-tetrahydro-1,3-benzodioxole-4,5-diol

2015 ◽  
Vol 71 (9) ◽  
pp. 1013-1016 ◽  
Author(s):  
Mario A. Macías ◽  
Leopoldo Suescun ◽  
Enrique Pandolfi ◽  
Valeria Schapiro ◽  
Gaurao D. Tibhe ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Dihedral Angle ◽  
Absolute Configuration ◽  
Title Compound ◽  
Membered Ring ◽  
X Ray Diffraction ◽  
X Ray ◽  
Compound C ◽  
The Mean

The absolute configuration of the title compound, C10H16O4, determined as 3aS,4S,5R,7aRon the basis of the synthetic pathway, was confirmed by X-ray diffraction. The molecule contains a five- and a six-membered ring that adopt twisted and envelope conformations, respectively. The dihedral angle between the mean planes of the rings is 76.80 (11)° as a result of theircis-fusion. In the crystal, molecules are linked by two pairs of O—H...O hydrogen bonds, forming chains along [010]. These chains are further connected by weaker C—H...O interactions along [100], creating (001) sheets that interact only by weak van der Waals forces.

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