X-Ray Structure of 6(E)-[2(Z)-(Hydroxyimino)-2-phenylethyIidene]- 7,7,8,8,9,9-hexamethyl-3-phenyl-1,2-oxazaspiro[4.4]non-2-ene

2001 ◽  
Vol 56 (4-5) ◽  
pp. 354-358
Author(s):  
Teresa Borowiak ◽  
Irena Wolska ◽  
Herbert Mayr ◽  
Janusz Baran
Keyword(s):  
Title Compound ◽  
Crystallographic Structure ◽  
Steric Strain ◽  
Orthorhombic Space Group ◽  
Compound A ◽  
X Ray ◽  
Cell Dimensions ◽  
Highly Strained ◽  
Centrosymmetric Dimers ◽  
Opposite Chirality

Abstract The X-ray crystallographic structure of the title compound, a product of a 1,3-dipolar cy­ cloaddition reaction of benzonitrile oxide to 3,3,4,4,5,5-hexamethyl-1,2-bis(methylene)cyclopentane, has been determined. Colourless plates crystallize in the orthorhombic space group Pbca with cell dimensions a = 13.698(2), b = 11.836(2), c = 29.157(4) Å, V= 4727.2(1.2)Å3, Z = 8, 3736 reflections, final R(F) = 0.063 and wR(F2) = 0.166. The crystals are racemic, the molecules of opposite chirality form centrosymmetric dimers via intermolecular hydro­ gen bonds O-H···N between their oxime groups. The molecules are highly strained and the geometrical consequences of the steric strain are discussed.

2R,4S-2-(2′-Methyl-3′-hydroxy-5′-hydroxymethylenepyridine-C4′)-5,5-dimethylthiazolidine-4-carboxylic acid, the product of the reaction of D-penicillamine and vitamin B6

1991 ◽  
Vol 69 (1) ◽  
pp. 1-7 ◽  
Author(s):  
R. Faggiani ◽  
H. E. Howard-Lock ◽  
C. J. L. Lock ◽  
R. Orgias
Keyword(s):  
Vitamin B6 ◽  
Geometrical Structure ◽  
X Ray Diffraction ◽  
Compound A ◽  
X Ray ◽  
H Nmr ◽  
Therapeutic Uses ◽  
Cell Dimensions ◽  
Pyridoxal Hydrochloride ◽  
Opposite Chirality

We have studied the reaction of both D- and L-penicillamine with pyridoxal hydrochloride and examined the products by single crystal X-ray diffraction. The structure of the title compound, A, formed by the reaction of D-penicillamine and pyridoxal was determined. Crystals are orthorhombic, P212121, with cell dimensions a = 9.507(5), b = 19.185(5), c = 7.766(2) Å and Z = 4. The structure was solved by standard methods and refined to R = 0.088, Rw = 0.079 for 2433 independent reflections. A exists as a zwitterion, and bond lengths and angles are normal. In the solid state, A and the corresponding product obtained from L-penicillamine, B, have identical geometrical structure but are of opposite chirality; that is, D-penicillamine produces the 2R,4S diastereomer and L-penicillamine produces the 2S,4R diastereomer (with no S,S and R,R components). In solution, however, NMR spectra show the presence of both pairs of diastereomers (2R,4S and 2S,4S; 2S,4R and 2R,4R). In neutral or alkaline solution there appears to be a rapid epimerization at the thiazolidine carbon atom attached to the pyridoxal moiety. Features of the mass, 1H NMR, vibrational, and electronic spectra are also discussed. Key words: D-penicillamine, vitamin B6, pyridoxal hydrochloride, therapeutic uses, bischemical reactions, structures.

Experimental evidence for the amino-group non-planarity in nitroanilines: neutron diffraction study of 2-methyl-5-nitroaniline at 100 K

1999 ◽  
Vol 55 (2) ◽  
pp. 209-215 ◽  
Author(s):  
Javier Ellena ◽  
Andrés E. Goeta ◽  
Judith A. K. Howard ◽  
Chick C. Wilson ◽  
Juan C. Autino ◽  
...  
Keyword(s):  
Molecular Recognition ◽  
Neutron Diffraction ◽  
Experimental Evidence ◽  
Diffraction Study ◽  
Title Compound ◽  
Neutron Diffraction Study ◽  
Amino Group ◽  
X Ray ◽  
Related Compounds ◽  
Centrosymmetric Dimers

An appreciable degree of pyramidalization of the amine N atom is observed in the title compound. The existence of polar chains, induced by N—H...O synthons, is confirmed. C—H...O interactions, not noted in a previous X-ray study, were found to stabilize further the known head-to-tail assembling of the chains. The structure can be described as non-polar (101) layers, embodying chains interlinked by centrosymmetric dimers, connected by C(aryl)—H...π interactions. The latter are not present in m-nitroaniline, 2-methyl-4-nitroaniline and other related compounds with chains built from similar N—H...O synthons and assembled head-to-head. This finding implies that an obvious relationship between molecular recognition patterns and crystal structures should not be assumed.

Structural and vibrational studies of 1,1,3,3-tetracyanopropane and 2,2,4,4,6-pentacyanocyclohexenamine

1987 ◽  
Vol 65 (2) ◽  
pp. 261-270 ◽  
Author(s):  
R. A. Bell ◽  
B. E. Brown ◽  
M. Duarte ◽  
H. E. Howard-Lock ◽  
C. J. L. Lock
Keyword(s):  
Unit Cell ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
X Ray Crystallography ◽  
New Methods ◽  
Cell Dimensions ◽  
Cell Data ◽  
Unit Cell Data ◽  
Monoclinic Cell ◽  
C Nmr

1,1,3,3-Tetracyanopropane, 1, was prepared in low yields by a literature method with 2,2,4,4,6-pentacyanocyclohexenamine, 2, as a major by-product. The products were examined by X-ray crystallography. 1 has an orthorhombic space group, Pbcn (No. 60) with cell dimensions, a = 7.158(2), b = 10.510(3), c = 9.733(2) Å and has four formula units in the unit cell. 2 has a monoclinic cell, P21/c (No. 14) with cell dimensions a = 14.368(3), b = 6.626(1), c = 12.300(2) Å, β = 115.60(1)° and has 4 formula units in the unit cell. Data were collected with use of MoKα radiation and a Nicolet P3 diffractometer. The crystal structures were determined by standard methods and refined to Rw = 0.037 (1) and Rw = 0.040 (2) on the basis of 782 and 2108 unique reflections. Bond lengths and angles in the two compounds are normal. 2 has what has been considered to be the less likely tautomeric structure. Both compounds were examined by 1H, 13C nmr, vibrational spectroscopy, and mass spectroscopy. For 2 there was no evidence of the alternative tautomeric structure. New methods were developed for the preparation of both compounds and the mechanism of the original reaction rationalized.

scholarly journals Crystal structure of 1,4-bis[5-(2-methoxyphenyl)-2H-tetrazol-2-yl]butane

2019 ◽  
Vol 75 (12) ◽  
pp. 1844-1847
Author(s):  
Young Min Byun ◽  
Farwa Ume ◽  
Ji Yeon Ryu ◽  
Junseong Lee ◽  
Hyoung-Ryun Park
Keyword(s):  
Title Compound ◽  
Methoxy Group ◽  
Coupling Reaction ◽  
Major Product ◽  
Molar Ratio ◽  
Dihedral Angles ◽  
X Ray ◽  
Compound C ◽  
Crystallographic Study ◽  
Centrosymmetric Dimers

The title compound, C20H22N8O2, was synthesized by the coupling reaction of a sodium tetrazolate salt and dibromobutane in a molar ratio of 2:1. The reaction can produce several possible regioisomers and the title compound was separated as the major product. The X-ray crystallographic study confirmed that the title compound crystallizes in the monoclinic P21/c space group and possesses a bridging butylene group that connects two identical phenyl tetrazole moieties. The butylene group is attached not to the first but the second nitrogen atoms of both tetrazole rings. The dihedral angles between the phenyl groups and the adjacent tetrazolyl rings are 5.32 (6) and 15.37 (7)°. In the crystal, the molecules form centrosymmetric dimers through C—H...O hydrogen bonds between a C—H group of the butylene linker and the O atom of a methoxy group.

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.

Crystallization and preliminary X-ray crystallographic studies on apolipoprotein H (β2-glycoprotein-I) from human plasma

1998 ◽  
Vol 54 (6) ◽  
pp. 1450-1452 ◽  
Author(s):  
Ajay Saxena ◽  
Anna Gries ◽  
Robert Schwarzenbacher ◽  
Gerhard M. Kostner ◽  
Peter Laggner ◽  
...  
Keyword(s):  
Human Plasma ◽  
Free Form ◽  
Data Sets ◽  
Asymmetric Unit ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
Human Plasma Protein ◽  
Glycoprotein I ◽  
Apolipoprotein H ◽  
Cell Dimensions

Apolipoprotein-H (Apo-H, Mw ≃ 50 kDa) is a carbohydrate-rich human-plasma protein which exists in blood serum in the free form as well as distributed between several classes of lipoproteins. Single crystals of apo-H have been obtained and crystallographic data sets have been collected. The crystals belong to the orthorhombic space group C2221, with cell dimensions a = 158.47, b = 169.25, c = 113.28 Å (at 100 K). The data indicate that the crystallographic asymmetric unit contains one tetramer of the protein.

Na2Si3O7: an incommensurate structure with crenel-type modulation functions, refined from a twinned crystal

2006 ◽  
Vol 62 (3) ◽  
pp. 440-446 ◽  
Author(s):  
Hannes Krüger ◽  
Volker Kahlenberg ◽  
Karen Friese
Keyword(s):  
Diffraction Data ◽  
Title Compound ◽  
Crystal Chemical ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
Left Handed ◽  
Sodium Cations ◽  
Incommensurate Structure ◽  
Orthorhombic Cell

The structure of metastable, incommensurately modulated Na2Si3O7 has been determined from single-crystal X-ray diffraction data. In contrast to previous investigations which stated that the compound crystallizes in an orthorhombic space group, this study shows that the compound is monoclinic with a pseudo-orthorhombic cell and is affected by twinning. The structure is described in the (3 + 1)-dimensional superspace. Crenel-type modulation functions are used to account for an aperiodic sequence of right- and left-handed zweier single chains of silicate tetrahedra. The modulation mainly affects one of the two symmetrically independent tetrahedral chains, which are connected to build up [Si3O7]2− layers. Sodium cations are coordinated by five oxygen ligands and provide linkage between adjacent tetrahedral sheets. Distortions of the silicate tetrahedra and crystal chemical relationships of the title compound to sodium and lithium di- and metasilicates are discussed in detail.

Crystallization and preliminary X-ray analysis of β-amylase from Bacillus polymyxa

1999 ◽  
Vol 55 (4) ◽  
pp. 898-900
Author(s):  
Takashi Yamane ◽  
Hiroshi Tasaki ◽  
Fusako Matsumoto ◽  
Atsuo Suzuki ◽  
Nobuyuki Uozumi ◽  
...  
Keyword(s):  
Diffusion Method ◽  
Bacillus Polymyxa ◽  
Asymmetric Unit ◽  
Hanging Drop ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
Cell Dimensions ◽  
Protein Molecules ◽  
Density Map ◽  
Electron Density Map

A truncated β-amylase (E.C. 3.2.1.2) from Bacillus polymyxa has been crystallized using the hanging-drop vapour-diffusion method at 277 K. The crystals belong to the orthorhombic space group P212121 with cell dimensions a = 64.6, b = 141.9, c = 155.1 Å and diffract to 2.5 Å resolution. The asymmetric unit containing three protein molecules was derived from an electron-density map calculated at 4 Å resolution using MIR phases. This gives a Vm value of 2.36 Å3 Da−1.

The crystal and molecular structure of tetrabenzocyclodecan-1,6-dione

1980 ◽  
Vol 58 (8) ◽  
pp. 777-779 ◽  
Author(s):  
T. Stanley Cameron ◽  
Christine Chan ◽  
David G. Morris ◽  
Alistair G. Shepherd
Keyword(s):  
Molecular Structure ◽  
Diffraction Analysis ◽  
Title Compound ◽  
Crystal And Molecular Structure ◽  
Membered Ring ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Nmr Spectrum ◽  
X Ray ◽  
C Nmr

The crystals belong to the orthorhombic space group C222, with a = 9.226, b = 12.092, c = 16.513 Å, Z = 4. A single crystal X-ray diffraction analysis has shown that the title compound, in which all carbon atoms are sp2 hybridized, exists with the ten membered ring in a slightly twisted tub conformation. The 13C nmr spectrum is also reported.

Polysulfonylamine, CIII [1] Ein Hydroxylamin mit bemerkenswert kurzer O-N-B Bindung: Kristall- und Molekülstruktur von MeO-N(SO2Me)2 / Polysulfonylamines, C III [1] A Hydroxylamine with a Remarkably Short O-N Bond: Crystal and Molecular Structure of MeO-N(SO2Me)2

1998 ◽  
Vol 53 (5-6) ◽  
pp. 634-636 ◽  
Author(s):  
Martina Näveke ◽  
Armand Blaschette ◽  
Peter G. Jones
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Low Temperature ◽  
Title Compound ◽  
Crystal And Molecular Structure ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray ◽  
Bond Angles

Abstract The crystal structure of the known title compound was determined by low-temperature X-ray diffraction (orthorhombic, space group Pbcn, Z = 4). The molecule displays an unusually short O-N bond, a relatively long C-O bond and a moderately pyramidal O-NS2 skeleton (O-N 133.1, C-O 148.5 pm, sum of bond angles at N: 347.4°).

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