The crystal structure of 5-O-Acetyl-1,2 : 3,4-di-O-isopropylidene-α-D-glucoseptanose, C14H22O7, by use of X-ray and neutrondiffraction data

1983 ◽  
Vol 36 (11) ◽  
pp. 2269 ◽  
Author(s):  
RA Wood ◽  
VJ James ◽  
AD Rae ◽  
JD Stevens ◽  
FH Moore
Keyword(s):  
Crystal Structure ◽  
Neutron Diffraction ◽  
Diffraction Analysis ◽  
Chair Conformation ◽  
Asymmetric Unit ◽  
Methyl Group ◽  
Neutron Diffraction Analysis ◽  
X Ray ◽  
Acetate Methyl ◽  
Independent Molecules

The crystal structure of 5-O-acetyl-1,2:3,4-di-O-isopropylidene-α-D-glucoseptanose [P212121, Z 8, a 14.329(5), b 22.075(5), c 10.012(5) �] has been determined by X-ray and neutron diffraction analyses. For the neutron diffraction analysis, the acetate group and the trans-O-isopropylidene group were deuterated. Constrained refinement was used in the neutron diffraction analysis to counter over parameterization in the block-diagonal least-squares refinement. Final unweighted R-values were 0.038 [X-ray for 3070 reflections with [Fo > 2.58σ (Fo)] and 0.061 [neutron for 1118 reflections with Fo > 4σ ([Fo)]The neutron refinement revealed a disordering of the acetate methyl group in each of the two independent molecules in the asymmetric unit. The septanose ring in each molecule adopted the same twist-chair conformation but the dioxolan rings assumed different twist and envelope conformations.

Constituents of Millingtonia hortensis: Isolation and Crystal Structure of trans-1-(2'-Hydroxyethyl)cyclohexane-1,4-diol

1989 ◽  
Vol 42 (8) ◽  
pp. 1397 ◽  
Author(s):  
K Naowsaran ◽  
BW Skelton ◽  
U Tooptakong ◽  
P Tuntiwachwuttikul ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Structure Determination ◽  
Chair Conformation ◽  
Cyclohexane Ring ◽  
Asymmetric Unit ◽  
X Ray ◽  
Independent Molecules

The isolation of trans-1-(2'-hydroxyethyl)cyclohexane-1,4-diol from the flowers of Millingtonia hortensis and its characterization, including a single-crystal X-ray structure determination at 295 K, is described. Crystals are triclinic, P1, a 12.348(5), b 11 .390(5), c 6.575(3) � , α 112.16(3), β 90.79(4), γ°, Z 4. R was 0.045 for 1475 independent 'observed', diffractometer reflections. In the two independent molecules of the asymmetric unit, the cyclohexane ring is in the usual 'chair' conformation with the ring hydroxy substituents occupying axial positions. The hydroxyethyl groups, however, adopt different orientations in the two molecules.

Crystal structure of cis-Tetracarbonylbis(chloromercury)iron

1976 ◽  
Vol 29 (9) ◽  
pp. 1905 ◽  
Author(s):  
CL Raston ◽  
AH White ◽  
SB Wild
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Diffraction Data ◽  
Title Compound ◽  
Direct Methods ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Independent Molecules

The crystal structure of the title compound has been determined by direct methods from X-ray diffraction data and refined by least squares to a residual of 0.071 for 2647 'observed' reflections. Crystals are monoclinic, C2/c, a = 36.81(1), b = 11.181(2), c = 20.369(5) �, β = 95.28(3)�, Z = 32. There are four independent molecules in the asymmetric unit, all with the cis disposition of ligands (<Fe-Hg), 2.498 �; <Hg-Fe-Hg), 80.9�); in one of the molecules one of the carbonyl sites is occupied by a more substantial moiety, possibly a result of partial occupancy of HgCl as a result of disorder or decomposition.

(1R,4S,8R,12S,13S,14R,16S,19R)-14-Hydroxy-7,7-dimethyl-17-methylene-2,9,18-trioxo-3,10-dioxapentacyclo[14.2.1.01,13.04,12.08,12]nonadec-19-yl acetate

2007 ◽  
Vol 63 (11) ◽  
pp. o4439-o4439
Author(s):  
Hao Shi
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Absolute Configuration ◽  
Title Compound ◽  
Chair Conformation ◽  
Boat Conformation ◽  
Asymmetric Unit ◽  
Compound C ◽  
Independent Molecules ◽  
The Absolute

The title compound, C22H26O8, prepared from the natural diterpenoid Macrocalyxin J, is built up from five fused rings. Cyclohenane ring A adopts a chair conformation, ring B exists in a screw-boat conformation and ring C adopts a boat conformation; the two five membered rings adopt envelope conformations. Two unique molecules are present in the asymmetric unit; both independent molecules have the same absolute configuration, the absolute configuration being deduced from the chirality of Macrocalyxin A, which was isolated from the same plant (i.e. Rabdosia macrocalyx) as Macrocalyxin J. The crystal structure displays intermolecular O—H...O hydrogen bonds.

scholarly journals Crystal structure ofN-[(4-ethoxyphenyl)carbamothioyl]cyclohexanecarboxamide

2015 ◽  
Vol 71 (11) ◽  
pp. o820-o821
Author(s):  
G. Vimala ◽  
J. Haribabu ◽  
S. Srividya ◽  
R. Karvembu ◽  
A. SubbiahPandi
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Chair Conformation ◽  
Cyclohexane Ring ◽  
Dihedral Angles ◽  
Asymmetric Unit ◽  
Compound C ◽  
The Mean ◽  
Independent Molecules ◽  
Ring Motif

The asymmetric unit of the title compound, C16H22N2O2S, contains two crystallographically independent molecules (AandB). In moleculeA, the cyclohexane ring is disordered over two orientations [occupancy ratio 0.841 (10):0.159 (10)]. In each molecule, the central carbonyl thiourea unit is nearly planar (r.m.s. deviations for all non-H atoms of 0.034 Å in moleculeAand 0.094 Å in moleculeB). In both molecules, the cyclohexane ring adopts a chair conformation. The mean plane of the cyclohexane ring makes dihedral angles of 35.8 (4) (moleculeA) and 20.7 (3)° (moleculeB) with that of the benzene ring. Each molecule features an intramolecular N—H...O hydrogen bond, which closes anS(6) ring motif. In the crystal, molecules are linkedviapairs of weak N—H...S interactions, forming inversion dimers with anR22(8) ring motif for both molecules. The crystal structure also features weak C—H...π ring interactions.

scholarly journals Crystal structure of (E)-N-cyclohexyl-2-(2-hydroxy-3-methylbenzylidene)hydrazine-1-carbothioamide

2019 ◽  
Vol 75 (7) ◽  
pp. 1065-1068
Author(s):  
Md. Azharul Arafath ◽  
Huey Chong Kwong ◽  
Farook Adam
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Title Compound ◽  
Chair Conformation ◽  
Cyclohexane Ring ◽  
Asymmetric Unit ◽  
Compound C ◽  
The Mean ◽  
Independent Molecules ◽  
Ring Motif

The asymmetric unit of the title compound, C15H21N3OS, comprises of two crystallographically independent molecules (A and B). Each molecule consists of a cyclohexane ring and a 2-hydroxy-3-methylbenzylidene ring bridged by a hydrazinecarbothioamine unit. Both molecules exhibit an E configuration with respect to the azomethine C=N bond. There is an intramolecular O—H...N hydrogen bond in each molecule forming an S(6) ring motif. The cyclohexane ring in each molecule has a chair conformation. The benzene ring is inclined to the mean plane of the cyclohexane ring by 47.75 (9)° in molecule A and 66.99 (9)° in molecule B. The mean plane of the cyclohexane ring is inclined to the mean plane of the thiourea moiety [N—C(=S)—N] by 55.69 (9) and 58.50 (8)° in molecules A and B, respectively. In the crystal, the A and B molecules are linked by N—H...S hydrogen bonds, forming `dimers'. The A molecules are further linked by a C—H...π interaction, hence linking the A–B units to form ribbons propagating along the b-axis direction. The conformation of a number of related cyclohexanehydrazinecarbothioamides are compared to that of the title compound.

Structure Investigations of Agonists of the Natural Neurotransmitter Acetylcholine VI [1]. X-Ray Structure Analysis of Trimethyl[2-(propionyloxy)ethyl]- ammonium-iodide (O-Propionylcholine-iodide)

1986 ◽  
Vol 41 (5-6) ◽  
pp. 641-646 ◽  
Author(s):  
Alfred Gieren ◽  
Michail Kokkinidis
Keyword(s):  
Crystal Structure ◽  
Nitrogen Atom ◽  
Formula Unit ◽  
Ammonium Iodide ◽  
Asymmetric Unit ◽  
Torsion Angles ◽  
Methyl Group ◽  
X Ray ◽  
Acetylcholine Chloride ◽  
Structure Investigations

The title compound (1) crystallizes in the orthorhombic, noncentrosymmetric space group Pna21 with a = 10.241(11), b = 12.903(12), c = 9.312(9) Å and with one formula unit per asymmetric unit. The stereochemically comparable torsion angles of the cation of 1 and of acetylcholine chloride are analogous. In the crystal structure the trimethylammonio methyl group is surrounded by three anions in the first coordination sphere. The geometry of a triangle formed by one of these counterions which occupies a special face of the N+C4 tetrahedron of the (CH3)3N+-CH2-R moiety, the nitrogen atom of the ammonium group and the oxygen atom of the carbonyl group is typical for nicotinic agonists.

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