Structure and conformation of hydroxylubimin, a sesquiterpenoid phytoalexin

1977 ◽  
Vol 55 (10) ◽  
pp. 1619-1623 ◽  
Author(s):  
George I. Birnbaum
Keyword(s):  
Structure Analysis ◽  
Direct Methods ◽  
Membered Ring ◽  
Side Chain ◽  
Equatorial Position ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray ◽  
Independent Molecules ◽  
Chiral Centers

In order to determine the orientation of the isopropenyl group and confirm the stereochemistry at other chiral centers in lubimin (1) and hydroxylubimin (2), two antifungal sesquiterpenes, an X-ray structure analysis of 2 was carried out. Crystals of 2 are orthorhombic, space group P212121, a = 6.190, b = 7.210, c = 63.082 Å, Z = 8. The structure was solved by direct methods and refined to R = 0.045. In both independent molecules the six-membered ring is chair-shaped with all four substituents equatorially oriented. The five-membered ring, attached by a spiro junction, is a half-chair with the isopropenyl substituent in an equatorial position. This side-chain is trans to the methyl-bearing carbon in the six-membered ring.

Titan(IV)-Fulvalenkomplexe. Darstellung und Struktur von [CpTiPh2l2(C10H8) / Titanium(IV) Fulvalene Complexes. Preparation and Structure of [CpTiPh2]2(C10H8)

1993 ◽  
Vol 48 (5) ◽  
pp. 603-607 ◽  
Author(s):  
Ulf Thewalt ◽  
Thomas Wöhrle
Keyword(s):  
Structure Analysis ◽  
Crystal Data ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray

The green insoluble TiIV compound which is obtained by treating titanocene with HC1 reacts with PhLi to yield the fulvalene-bridged compound [CpTiPh2]2(C10Hg) 3(Ph). An X-ray structure analysis of 3(Ph) shows, that the Ti atoms are in a trans arrangement with respect to the fulvalene group. Crystal data for 3(Ph) are as follows: C44H38Ti2, orthorhombic, space group P212,1 21, with a = 11,385(2), b = 14,510(2), c = 19,489(4) Å, Z = 4. The crystals exhibit enantiomorphism.

Zur Darstellung und Struktur des 1.3-Dichloro-5-N.N-dimethylamino-1.3-dithia-2.4.6-triazins / Synthesis and Structure of 1,3-Dichloro-5-N,N-dimethylamino-1,3-dithia-2,4,6-triazine

1983 ◽  
Vol 38 (3) ◽  
pp. 347-349 ◽  
Author(s):  
Herbert W. Roesky ◽  
Pierre Schäfer ◽  
Mathias Noltemeyer ◽  
George M. Sheldrick
Keyword(s):  
Structure Analysis ◽  
Nmr Spectra ◽  
Membered Ring ◽  
Monoclinic Space Group ◽  
Space Group ◽  
X Ray ◽  
Cl Atoms ◽  
C Nmr

Abstract The six membered ring of composition (CH3)2NCN3S2Cl2 3 a was prepared from N,N-dimethylguanidinhydrochloride and trithiadiazindichloride. 3 a was characterized on the basis of mass, 1H, 13C NMR spectra and X-ray structure analysis. Crystals of 3 a are monoclinic, space group P21/c, with a = 660.3(6), b = 834.5(7), c = 1774.7(15) pm, β = 112.83(6)° and Z = 4. The C2N unit lies approximately in the plane of the [-CNSNSN-] ring, with both Cl atoms on the same side of the ring.

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.

Synthese Und Kristallstrukturen Von Chlorometallaten [M = V(III), Mo(V)]

2001 ◽  
Vol 56 (8) ◽  
pp. 759-764 ◽  
Author(s):  
Soheila Chitsaz ◽  
Effat Iravani ◽  
Jochen Pauls ◽  
Bernhard Neumüller
Keyword(s):  
Ir Spectroscopy ◽  
Membered Ring ◽  
Dinuclear Complex ◽  
Monoclinic Space Group ◽  
Asymmetric Unit ◽  
Space Group ◽  
X Ray ◽  
X Ray Crystallography ◽  
Independent Molecules ◽  
Triclinic Form

[(THF)2LiCl2VCl2(THF)2] (1) and [Li(THF)4][OMoCl4(THF)] (2) can be prepared by the reactions of VCI3 with LiCl in THF and of Li(H)PtBu with OM0 CI4 in THF, respectively. 1 and 2 were characterized by IR spectroscopy, MS spectrometry (2) and X-ray crystallography. 1 can be obtained in two modifications depending on the temperature of crystallization. At -30 °C a triclinic form, 1a, was isolated from THF solution with one unique molecule per asymmetric unit. However, at 20 °C, 1b crystallized in the monoclinic space group P2/c. It possesses four independent molecules per asymmetric unit. According to the structure analyses 1 consists of a dinuclear complex with a planar LiCl2V four-membered ring while 2 consists of seperate ions [Li(THF)4]+ and [OMoCl4(THF)]-

scholarly journals X-ray structure analysis of symmetrically substituted 1,1′-diformylruthenocene

2018 ◽  
Vol 74 (9) ◽  
pp. 1186-1189
Author(s):  
Bertin Anzaldo ◽  
Pankaj Sharma ◽  
Francisco Lara Ochoa ◽  
Claudia P. Villamizar C. ◽  
René Gutiérrez Pérez
Keyword(s):  
Structure Analysis ◽  
Room Temperature ◽  
Dimensional Structure ◽  
Two Dimensional ◽  
Asymmetric Unit ◽  
Orthorhombic System ◽  
Space Group ◽  
X Ray ◽  
Π Interactions ◽  
Independent Molecules

1,1′-Diformylruthenocene, [Ru(C6H5O)2], crystallizes in the orthorhombic system in the P212121 space group at room temperature. There are two crystallographically independent molecules in the asymmetric unit. The cyclopentadienyl rings have eclipsed configuration. The molecules self-assemble in a two-dimensional structure by C—H...O and C—H...π interactions with cisoid relative orientations of the two formyl groups. The crystal studied was refined as an inversion twin.

Silaheterocyclen: Molekülstruktur eines 3-Oxa-2,4,6,7-tetrasilabicyclo[3.1.1]heptans / Silaheterocycles: Molecular Structure of a 3-Oxa-2,4,6,7-tetrasilabicyclo[3.1.1]heptane

1989 ◽  
Vol 44 (7) ◽  
pp. 796-799 ◽  
Author(s):  
Gabriele Reber ◽  
Jürgen Riede ◽  
Nils Wiberg ◽  
Gerhard Wagner ◽  
Gerhard Müller
Keyword(s):  
Molecular Structure ◽  
Dihedral Angle ◽  
Structure Analysis ◽  
Membered Ring ◽  
Triclinic Space Group ◽  
Space Group ◽  
X Ray

According to an X-ray structure analysis 1,5-bis(di-tert-butylmethylsilyl)-2,2,4,4,6,6,7,7-octamethyl-3-oxa-2,4,6,7-tetrasilabicyclo[3.1.1]heptane (1) is a rigid bicyclic molecule consisting of a 1,3-disilacyclobutane ring whose 2,4 positions are bridged by a Me2Si—O—SiMe2 fragment. The four-membered ring is non-planar with a dihedral angle of 33.8° along the C—C axis. The intraring valence angles at carbon are significantly smaller than those at silicon leading to a transannular Si ··· Si distance of only 2.558(1) Å (triclinic, space group P 1̄ with a = 9.125(2), b = 12.668(2), c = 15.499(3) Å, α = 101.25(1), β = 87.87(1), γ = 96.88(1)°, V = 1744.4 Å3 R (wR) = 0.044 (0.051) for 316 refined parameters and 5156 observables).

The Two-step Synthesis and Crystal and Molecular Structure of Tetracyclo[6.4.0.02,11.04,9]dodec-6-ene-3,10-dione

1975 ◽  
Vol 53 (14) ◽  
pp. 2068-2075 ◽  
Author(s):  
Yuen-Mui Ngan ◽  
Steven J. Rettig ◽  
John R. Scheffer ◽  
James Trotter
Keyword(s):  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Membered Ring ◽  
Diels Alder ◽  
High Yield ◽  
Side Chain ◽  
X Ray ◽  
Long Wavelength ◽  
Vinyl Group ◽  
Alder Adduct

The photochemistry of the trans-1,3,5-hexatriene-p-benzoquinone Diels–Alder adduct has been investigated. Irradiation of this material in its long wavelength n → π* absorption band leads to a single photoproduct in high yield. A single crystal X-ray structure determination shows this product to be tetracyclo[6.4.0.02,11.04,9]dodec-6-ene-3,10-dione, the result of a novel regiospecific intramolecular 2 + 2 photoaddition between the side chain vinyl group and the enedione double bond. Crystals of tetracyclo[6.4.0.02,11.04,9]dodec-6-ene-3,10-dione are monoclinic, a = 7.5290(7), b = 19.072(1), c = 6.7237(4) Å, β = 107.918(6) °, Z = 4, space group P21/n. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to a final R of 0.041 for 1603 reflections with I ≥ 3σ(I). The structure consists of well-separated molecular units. Bond distances are: C=O, 1.216 and 1.219(2), C=C, 1.318(2), mean C(sp3)—C(sp2), 1.508, mean C(sp3)—C(sp3), 1.560 in the four-membered ring and 1.544 elsewhere, mean C(sp3)—H, 0.99, and mean C(sp2)—H, 0.95 Å. Bond distances between nonhy drogen atoms have been corrected for thermal motion. A possible rationalization for the observed photoprocess is discussed in terms of conformational and radical stability effects.

Beiträge zur Strukturchemie phosphorhaltiger Ketten und Ringe, IX [1]. Die Molekül- und Kristallstruktur von Tri-tert-butylcyclotriphosphanpentacarbonyl- chrom(O), [(t-BuP)3Cr(CO)5] / Structural Chemistry of Phosphorus-Containing Chains and Rings, IX [1]. The Molecular and Crystal Structure of Tri-tert-butylcydotriphosphane-pentacarbonyl-chromium (0), [(t-BuP)3Cr(CO)5]

1984 ◽  
Vol 39 (1) ◽  
pp. 37-42 ◽  
Author(s):  
Karl-Friedrich Tebbe ◽  
Magda Fehér
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Least Squares ◽  
Direct Methods ◽  
Membered Ring ◽  
Free Molecule ◽  
Donor Ligand ◽  
Space Group ◽  
X Ray ◽  
Phosphorus Containing

The structure of [(t-BuP)3Cr(CO)5], C17CrH27O5P3, has been determined by single crystal X-ray techniques, solved by ‘direct methods', and refined to R = 0.048, wR = 0.050 for 3657 reflections by blocked least squares. The compound crystallizes in the space group P 21/c with a = 1664.9 pm, b = 916.5 pm , c = 3089.8 pm, β= 91.45° and Z = 8 formula units. The structure consists of two crystallographically independent but structurally nearly identical mononuclear [(t-BuP)3Cr(CO)5] complexes with the three-membered ring (t-BuP)3 as an unidentate σ-donor ligand. Compared to the free molecule (t-BuP)3 the cyclophosphane ligand is slightly distorted on account of its coordination to the Cr(CO)5-group.

Crystal structures of two lactones of the bicyclo[2,2,2]octane series

1982 ◽  
Vol 35 (2) ◽  
pp. 457 ◽  
Author(s):  
RM Carman ◽  
SS Smith ◽  
CHL Kennard ◽  
G Smith ◽  
AH White ◽  
...  
Keyword(s):  
Least Squares ◽  
Crystal Structures ◽  
Three Dimensional ◽  
Direct Methods ◽  
Monoclinic Space Group ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray ◽  
A Cell

The crystal structures of two γ-lactones of the bicyclo[2,2,2]octane series, endo-3-carboxy-exo-5- iodobicyclo[2,2,2]octane-2,6-carbolactone (2; R = CO2H) and exo-3-methoxycarbonyl-endo-5-acetoxybicyclo[2,2,2] octane-2,6-carbolactone (7b), have been determined by direct methods from three-dimensional X-ray data and refined by least-squares to final residuals of 0.033 (2; R = CO2H) and 0.036 (7b) for 1918 and 630 'observed' reflections respectively. Crystals for (2; R = CO2H) are monoclinic, space group P21/c with Z 8 in a cell of dimensions a 7.192(2), b 23.785(8), c 13.199(5) �, β 105.35(2)�, while (7b) crystallizes in the orthorhombic space group P212121 with Z 4 in a cell of dimensions a 13.347(7), b 11.839(7), c 8.227(11) �.

scholarly journals Darstellung und Charakterisierung der μ3-Oxo-Cluster [Cp3Mo3(CO)4µ-Cl)(µ3-O)] und [Cp3Mo3(µ-CO)3(CO)3(µ3-O)]+ / Synthesis and Characterization of the µ3-Oxo Clusters [Cp3Mo3(CO)4μ-Cl)(μ3-O)] and [Cp3Mo3(μ-CO)3(CO)3(μ3-O)]+

1990 ◽  
Vol 45 (4) ◽  
pp. 508-514 ◽  
Author(s):  
B. Nuber ◽  
W. Schatz ◽  
M. L. Ziegler
Keyword(s):  
Structure Analysis ◽  
Elemental Analysis ◽  
Spectroscopic Data ◽  
Synthesis And Characterization ◽  
Monoclinic Space Group ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray

[CpMo(CO)3]2 (1) (Cp = cyclopentadienyl) reacts with InCl3 in diglyme to yield the oxo-cluster [Cp3Mo3(CO)4(μ-Cl)(μ3-O)] (2) and the cationic oxo-cluster [Cp3Mo3(μ-CO)3(CO)3(μ3-O)]+ as the salt [Cp3Mo3(μ-CO)3(CO)3(μ3-O)][CpMo(CO)3InCl3] (3). The compounds were characterized by elemental analysis, spectroscopic data and X-ray structure analysis. Compound 2 crystallizes in the orthorhombic space group P212121 with a = 1006.0(3), b = 1244.6(4) and c = 1600.8(5) pm, V = 2004.3 x 106 pm3, Z = 4. Compound 3 crystallizes in the monoclinic space group P 21/m with a = 874.4(8), b = 1407(1) and c = 1500(1) pm, β = 92.95(6) , V = 1843 × 106 pm3, Z = 2.

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