scholarly journals Crystal structure of (−)-(2R,3S,4R,5R)-5-(1,3-dithian-2-yl)-3-methyl-1-(triisopropylsilyloxy)hexane-2,4-diol

2014 ◽  
Vol 70 (12) ◽  
pp. o1285-o1286 ◽  
Author(s):  
Alejandra Cruz-Montanez ◽  
Dalice M. Piñero Cruz ◽  
Jose A. Prieto
Keyword(s):  
Crystal Structure ◽  
Primary Alcohol ◽  
Resonant Scattering ◽  
Chair Conformation ◽  
Anomalous Scattering ◽  
Silyl Ether ◽  
Asymmetric Unit ◽  
Compound C ◽  
Independent Molecules ◽  
Absolute Structure

The title compound, C20H42O3S2Si, crystallized with two independent molecules (AandB) in the asymmetric unit. They consist ofsyn,anti,anti-stereotetrads with a 1,3-dithiane motif and a primary alcohol protected as the triisopropyl silyl ether. The 1,3-dithiane ring adopts a chair conformation, while the rest of each molecule displays a common zigzag conformation. There is an intramolecular O—H...O hydrogen bond in each molecule. In the crystal, theAandBmolecules are linkedviaO—H...O hydrogen bonds, forming –A–B–A--B-- chains along [010]. The absolute structure was determined by resonant scattering (anomalous scattering) [Flack parameter = 0.035 (8)].

(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.

scholarly journals Crystal structure of (1S,2R,4S)-1-[(morpholin-4-yl)methyl]-4-(prop-1-en-2-yl)cyclohexane-1,2-diol

2015 ◽  
Vol 71 (1) ◽  
pp. 79-81 ◽  
Author(s):  
Rachid Outouch ◽  
Saadia Oubaassine ◽  
Mustapha Ait Ali ◽  
Larbi El Firdoussi ◽  
Anke Spannenberg
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Absolute Configuration ◽  
Title Compound ◽  
Chair Conformation ◽  
Asymmetric Unit ◽  
Compound C ◽  
Synthetic Procedure ◽  
Independent Molecules ◽  
The Absolute

The asymmetric unit of the title compound, C14H25NO3, contains two independent molecules with similar geometry. The morpholine and cyclohexane rings of both molecules adopt a chair conformation. Intramolecular O—H...N hydrogen bonds are observed. In the crystal, molecules are linked by O—H...O hydrogen bonds into chains parallel to the [101] direction. The chains are further connected through C—H...O hydrogen bonds forming undulating layers parallel to the (-101) plane. The absolute configuration was assigned by reference to an unchanging chiral centre in the synthetic procedure.

scholarly journals Crystal structure of 5-chloromethyl-N-methyl-4-[(4-phenyl-1,2,3-triazol-1-yl)methyl]isoxazolidine-3-carboxamide

2016 ◽  
Vol 72 (3) ◽  
pp. 378-381
Author(s):  
Jihed Brahmi ◽  
Soumaya Nasri ◽  
Kaïss Aouadi ◽  
Erwann Jeanneau ◽  
Sébastien Vidal ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Phenyl Ring ◽  
Triazole Ring ◽  
Resonant Scattering ◽  
Asymmetric Unit ◽  
Compound C ◽  
Independent Molecules

The title compound, C15H18ClN5O2, crystallizes with two independent molecules (AandB) in the asymmetric unit. In both molecules, the isoxazolidine rings have an envelope conformation with the O atoms at the flap positions. Each molecule has three stereogenic centres with configurations 2(S), 3(S) and 4(R), confirmed by resonant scattering. Their conformations are significantly different, for example in moleculeAthe phenyl ring is inclined to the triazole ring by 32.5 (2)°, while in moleculeBthe corresponding dihedral angle is 10.7 (2)°. In the crystal, theAandBmolecules are linkedviaan N—H...O and a C—H...O hydrogen bond. These units are linked by C—H...O and C—H...N hydrogen bonds, forming slabs parallel to theabplane. There are C—H...π interactions present within the slabs.

scholarly journals 12α-Hydroxy-3,27-dioxooleanano-28,13-lactone

2012 ◽  
Vol 68 (6) ◽  
pp. o1586-o1586 ◽  
Author(s):  
Jun-yi Hu ◽  
Gang-gang Wu ◽  
Ying-qian Xu ◽  
Guo-yong Xiao ◽  
Peng Lei
Keyword(s):  
Crystal Structure ◽  
Double Bond ◽  
Hydrogen Bonds ◽  
Lactone Ring ◽  
Chair Conformation ◽  
The Other ◽  
Carbonyl Groups ◽  
Asymmetric Unit ◽  
Compound C ◽  
Independent Molecules

There are two independent molecules in the asymmetric unit of the title compound, C30H44O5. They comprise a triterpenoid skeleton of five six-membered rings and a five-membered lactone ring. The five six-membered rings are all trans-fused. In both independent molecules the D rings adopt a slightly distorted half-chair conformation due the presence of the lactone ring while the other four six-membered rings all adopt chair conformations. The characteristic carbon–carbon double bond of the oleanoic skeleton is absent. Intermolecular O—H...O hydrogen bonds between the hydroxy and carbonyl groups occur in the crystal structure.

4,4,7,7-Tetramethyl-2-tosyl-2,3,3a,4,6,7,8,9-octahydro-1H-pyrrolo[3,4-c]pyrano[6,5-b]cyclohexan-9-one

2007 ◽  
Vol 63 (11) ◽  
pp. o4436-o4437 ◽  
Author(s):  
K. Chinnakali ◽  
D. Sudha ◽  
M. Jayagopi ◽  
R. Raghunathan ◽  
Hoong-Kun Fun
Keyword(s):  
Crystal Structure ◽  
Three Dimensional ◽  
Chair Conformation ◽  
Ring System ◽  
Asymmetric Unit ◽  
Pyrrolidine Ring ◽  
Compound C ◽  
Twist Conformation ◽  
Tosyl Group ◽  
Independent Molecules

The title compound, C22H29NO4S, crystallizes with three independent molecules, A, B and C, in the asymmetric unit. Each of the three independent molecules adopts a folded conformation, with the phenylsulfonyl group lying over the pyranocyclohexanone ring system, and with the pyrrolidine and dihydropyran rings cis-fused. In all three molecules, the pyrrolidine ring has a twist conformation and the dihydropyran ring is in a half-chair conformation. The cyclohexenone rings adopt envelope conformations, with the flap atom puckered towards the phenylsulfonyl group in molecule A, and away from that group in molecules B and C, resulting in a different overall conformation for molecule A compared to B and C. In all molecules, the tosyl group is equatorially attached to the pyrrolidine ring. In the crystal structure, the molecules are linked into a three-dimensional framework by C—H...O hydrogen bonds.

scholarly journals Crystal structure of 3,4a,7,7,10a-pentamethyl-3-vinyldodecahydro-1H-benzo[f]chromen-9-ol isolated fromSideritis perfoliata

2016 ◽  
Vol 72 (10) ◽  
pp. 1380-1382 ◽  
Author(s):  
Ísmail Çelik ◽  
Cem Cüneyt Ersanlı ◽  
Rahmi Köseoğlu ◽  
Hüseyin Akşit ◽  
Ramazan Erenler ◽  
...  
Keyword(s):  
Quantum Chemical ◽  
Chair Conformation ◽  
Van Der Waals Interactions ◽  
Asymmetric Unit ◽  
Screw Axis ◽  
X Ray ◽  
Compound C ◽  
Independent Molecules ◽  
Semi Empirical ◽  
Absolute Structure

The asymmetric unit of the title compound, C20H34O2, contains two crystallographically independent molecules (1 and 2) with similar conformations. In both molecules, the cyclohexane rings adopt a chair conformation, while the oxane rings are also puckered. In the crystal, O—H...O hydrogen bonds connect adjacent molecules, formingC(6) helical chains located around a 21screw axis and running along the crystallographicaaxis. The packing of these chains is governed only by van der Waals interactions. Semi-empiricalPM3quantum chemical calculations are in a satisfactory agreement with the structural results of the X-ray structure analysis. The absolute structure was indeterminate in the present experiment.

scholarly journals 8-Methoxy-3-methyl-3,4-dihydro-2H-1,3-benzoxazine

2013 ◽  
Vol 69 (11) ◽  
pp. o1619-o1619
Author(s):  
Jing Zhu ◽  
Xiang-Xiang Yang ◽  
Long-Yu Xu ◽  
Zhi-Dong Ren ◽  
Ling-Bo Qu
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Chair Conformation ◽  
Asymmetric Unit ◽  
Π Interactions ◽  
Compound C ◽  
Independent Molecules

The title compound, C10H13NO2, crystallizes with two crystallographically independent molecules of similar geometry in the asymmetric unit; the six-membered oxazine rings adopts a half-chair conformation. Neither hydrogen bonds nor π–π interactions are observed in the crystal structure.

scholarly journals Crystal structure of (1S,3R,8R,10S)-2,2-dichloro-10-hydroxy-3,7,7,10-tetramethyltricyclo[6.4.0.01,3]dodecan-9-one

2016 ◽  
Vol 72 (5) ◽  
pp. 709-711
Author(s):  
Ahmed Benzalim ◽  
Aziz Auhmani ◽  
My Youssef Ait Itto ◽  
Jean-Claude Daran ◽  
Auhmani Abdelwahed
Keyword(s):  
Crystal Structure ◽  
Cyclopropane Ring ◽  
Resonant Scattering ◽  
Asymmetric Unit ◽  
Alcohol Group ◽  
Bond Forming ◽  
Compound C ◽  
Independent Molecules ◽  
Cl Atoms ◽  
Ring Motif

The asymmetric unit of the title compound, C16H24Cl2O2, contains two independent molecules (AandB) which are built from three fused rings,viz.a seven-membered heptane ring, a six-membered cyclohexyl ring bearing a ketone and an alcohol group, and a cyclopropane ring bearing two Cl atoms. In the crystal, the two molecules are linkedviatwo O—H...O hydrogen bonds, forming anA–Bdimer with anR22(10) ring motif. TheAmolecules of these dimers are linkedviaa C—H...O hydrogen bond, forming chains propagating along thea-axis direction. Both molecules have the same absolute configuration,i.e.1S,3R,8R,10S, which is based on the synthetic pathway and further confirmed by resonant scattering [Flack parameter = 0.03 (5)].

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