共查询到20条相似文献,搜索用时 515 毫秒
1.
Michael Benn Masood Parvez Oliver Edward Edwards 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(5):o283-o285
The structure of the title compound, C23H35NO4, contains a unique pentacyclic ring system wherein one cyclohexyl ring adopts a chair conformation, two cyclohexyl rings are in boat conformations, and a six‐membered heterocyclic ring and a cyclopentyl ring are in envelope conformations. The structures of the lycoctamones, α,β‐unsaturated aldehydes produced by acid‐catalyzed degradation of lactams of lycoctonine‐type alkaloids, previously deduced from the results of extensive chemical investigations have been proven to be correct by the determination of the crystal structure of this compound. 相似文献
2.
Michael Bolte Alexander Degen Stephan Rühl 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(4):446-451
We have determined the crystal structures of 2,2′‐(4‐fluorophenyl)methylenebis(3‐hydroxy‐5,5‐dimethyl‐2‐cyclohexen‐1‐one), C23H27FO4, (I), 2,2′‐(4‐chlorophenyl)methylenebis(3‐hydroxy‐5,5‐dimethyl‐2‐cyclohexen‐1‐one), C23H27ClO4, (II), 2,2′‐(4‐hydroxyphenyl)methylenebis(3‐hydroxy‐5,5‐dimethyl‐2‐cyclohexen‐1‐one), C23H28O5, (III), 2,2′‐(4‐methylphenyl)methylenebis(3‐hydroxy‐5,5‐dimethyl‐2‐cyclohexen‐1‐one), C24H30O4, (IV), 2,2′‐(4‐methoxyphenyl)methylenebis(3‐hydroxy‐5,5‐dimethyl‐2‐cyclohexen‐1‐one), C24H30O5, (V), and 2,2′‐(4‐N,N′‐dimethylaminophenyl)methylenebis(3‐hydroxy‐5,5‐dimethyl‐2‐cyclohexen‐1‐one), C25H33NO4, (VI). Structures (III) to (VI) of these bis‐dimedone derivatives show nearly the same packing pattern irrespective of the different substituent in the para position of the aromatic ring. However, (II) does not fit into this scheme, although the Cl atom is a substituent not too different from the others. The different packing of the fluoro compound, (I), can be explained by the fact that it crystallizes with two molecules in the asymmetric unit, which show a different conformation of the dimedone ring. On the other hand, (I) shows a similar packing pattern to bis(2‐hydroxy‐4,4‐dimethyl‐6‐oxo‐1‐cyclohexenyl)phenylmethane, a compound containing an aromatic ring without any substituent and with Z′ = 2. 相似文献
3.
N. Ourhriss M. Giorgi N. Mazoir A. Benharref 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(12):o699-o701
The title compound, (1S,3R,8R)‐2,2‐dichloro‐3,7,7,10‐tetramethyltricyclo[6.4.0.01,3]dodecan‐11‐one thiosemicarbazone, C17H25Cl2N3S, has two disordered conformations of the cycloheptane moiety and a screw‐boat conformation for the cyclohexene ring. The absolute configuration was established. 相似文献
4.
Latif Kelebekli Yunus Kara Metin Balci Ertan ahin 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(7):o432-o434
In the title compound, C16H20Cl2O8, the bicyclic system contains a central non‐planar cyclohexane ring which is fused to a cyclobutane moiety. The cyclohexane ring has a chair conformation and the whole system adopts a syn conformation. The structure provides information on the stereochemical course of the chlorination, photo‐oxidation and hydroxylation steps of the reaction. 相似文献
5.
Bertrand Vivet Florine Cavelier Jean Martinez Claude Didierjean Michel Marraud Andre Aubry 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(12):1452-1454
The silaproline‐containing dipeptide N‐(3,3‐dimethyl‐1‐pivaloyl‐1‐aza‐3‐sila‐5‐cyclopentylcarbonyl)‐l ‐alanine isopropylamide, C17H33N3O3Si, has two independent molecules in the asymmetric unit and each adopts a β‐II folded conformation, where the amide on the terminal C interacts intramolecularly with the pivaloyl O atom. The five‐membered silaproline ring is Cβ‐puckered, an infrequent conformation for the homologous proline ring. 相似文献
6.
Won Seok Han Soon W. Lee 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(4):m189-m190
In the title compound, azido‐2κN‐bis[μ‐(1η5:2κP)‐diphenylphosphinocyclopentadienyl][2(η5)‐pentamethylcyclopentadienyl]iron(III)rhodium(III) hexafluorophosphate, [{Rh(C10H15)(N3)}{Fe(μ‐C17H14P)2}]PF6 or [FeRh(C10H15)(μ‐C17H14P)2(N3)]PF6, the coordination sphere of RhIII can be described as pseudo‐tetrahedral, composed of two P atoms from a 1,1′‐bis(diphenylphosphino)ferrocene (dppf) ligand, an azido N atom and the centroid of the ring of a C5Me5 (Cp*) ligand. The two cyclopentadienyl rings in the dppf moiety adopt an eclipsed conformation. The Rh⋯Fe distance is 4.340 (2) Å. 相似文献
7.
A. David Brewer George Ferguson Andrew A. Znotins 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(3):e109-e110
The structures of a 2‐oxa‐5‐thiabicyclo[4.1.0]heptane derivative, C7H10Cl2O3S, (I), and a 2H,3H,5H‐1,4‐dithiepine derivative, C7H9ClO4S2, (II), are reported. The six‐membered ring in (I) has an envelope conformation and the seven‐membered ring in (II) adopts a chair conformation. There are no untoward intermolecular interactions in (I), but two Cl atoms make a short intermolecular contact across an inversion centre in (II), with a Cl?Cl distance of 3.2784 (9) Å, some 0.22 Å less than the sum of the van der Waals radii. 相似文献
8.
Laura Andrau Jonathan White 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(2):o60-o61
The crystal structure of N‐methyl‐4‐piperidyl 2,4‐dinitrobenzoate, C13H15N3O6, (I), at 130 (2) K reveals that, in the solid state, the molecule exists in the equatorial conformation, (Ieq). Thus, the through‐bond interaction present in the axial conformation, (Iax), is not strong enough to overcome the syn–diaxial interactions between the axial methyl substituent and the axial H atoms on the two piperidyl ring C atoms either side of the ester‐linked ring C atom. The carboxylate group in (I) is orthogonal to the aromatic ring, in contrast with other 2,4‐dinitrobenzoates, which are coplanar. The piperidyl–ester C—O bond distance is 1.467 (3) Å, which is actually shorter than other equatorial cyclohexyl–ester C—O distances. This shorter piperidyl–ester C—O bond distance is due to the reduced electron demand of the orthogonal ester group. 相似文献
9.
Mario Cetina Senka ?akovi Vladimir Rapi Amalija Golobi
《Acta Crystallographica. Section C, Structural Chemistry》2003,59(8):m328-m330
In the title compound, [Fe(C5H5)(C14H13O)], the plane of the heterocyclic ring is almost perpendicular to the plane of the substituted cyclopentadienyl ring, and the heterocyclic ring adopts a half‐chair conformation. The conformation of the nearly parallel cyclopentadienyl (Cp) rings [the dihedral angle between their planes is 2.7 (1)°] is almost halfway between eclipsed and staggered, and the rings are mutually twisted by about 19.4 (2)° (mean value). The mean lengths of the C—C bonds in the substituted and unsubstituted cyclopentadienyl ring are 1.420 (2) and 1.406 (3) Å, respectively, and the Fe—C distances range from 2.029 (2) to 2.051 (2) Å. The phenyl and unsubstituted cyclopentadienyl rings are involved in C—H⃛π interactions, with intermolecular H⃛centroid distances of 2.85 and 3.14 Å for C—H⃛π(Ph), and 2.88 Å for C—H⃛π(Cp). In two of these interactions, the C—H bond points towards one of the ring bonds rather than towards the ring centroid. In the crystal structure, the C—H⃛π interactions connect the molecules into a three‐dimensional framework. 相似文献
10.
Akira Uchida Masatoshi Hasegawa Hiroshi Manami 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(8):o435-o438
cis,cis,cis‐1,2,4,5‐Cyclohexanetetracarboxylic acid, C10H12O8, (I), contains a mirror plane and the cyclohexane ring exhibits a chair conformation. Two crystallographically independent hydrogen bonds form (14), (16) and (16) ring motifs, and propagation of these two hydrogen bonds along the c and b axes generates (16) and (7) chains. cis,cis,cis‐1,2:4,5‐Cyclohexanetetracarboxylic dianhydride, C10H8O6, (II), was prepared by the reaction of (I) with acetic anhydride. The cyclohexane ring of (II) exhibits a boat conformation and the dihedral angle between the two anhydro rings is 117.5 (1)°. 相似文献
11.
Swastik Mondal Monika Mukherjee Arnab Roy Debabrata Mukherjee 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(3):o132-o134
In the title tricyclic keto‐diester, C20H24O6, a potential intermediate in the synthesis of bioactive podocarpic acid, the outer cyclohexane ring (in a chair conformation) is cis fused to the central cyclohexanone ring (in a half‐chair conformation). The conformational analysis of the compound, investigated by semi‐empirical quantum mechanical AM1 calculations, shows a good agreement with the X‐ray structure, except for the orientation of the methyl, methoxyphenyl and methoxycarbonyl substituents. 相似文献
12.
Ivan Leban Lovro Seli
Toma Mesar Anton opar Tom olmajer 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(6):o367-o369
The molecular structure of the title tricyclic compound, C17H21NO4, which is the immediate precursor of a potent synthetic inhibitor {Lek157: sodium (8S,9R)‐10‐[(E)‐ethylidene]‐4‐methoxy‐11‐oxo‐1‐azatricyclo[7.2.0.03,8]undec‐2‐ene‐2‐carboxylate} with remarkable potency, provides experimental evidence for the previously modelled relative position of the fused cyclohexyl ring and the carbonyl group of the β‐lactam ring, which takes part in the formation of the initial tetrahedral acyl–enzyme complex. In this hydrophobic molecule, the overall geometry is influenced by C—H?O intramolecular hydrogen bonds [3.046 (4) and 3.538 (6) Å, with corresponding normalized H?O distances of 2.30 and 2.46 Å], whereas the molecules are interconnected through intermolecular C—H?O hydrogen bonds [3.335 (4)–3.575 (5) Å]. 相似文献
13.
B. de Castro C. Freire M. Teresa Duarte M. F. Minas da Piedade I. C. Santos 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(4):370-372
In the title complex, trans‐{2,2′‐[cyclohexane‐1,2‐diylbis(nitrilomethylidyne)]diphenolato‐κ4O,N,N′,O′}nickel(II)–chloroform (1/1), [Ni(C20H20N2O2)]·CHCl3, the Ni atom has a square‐planar geometry, slightly tetrahedrally distorted. The Ni—N and Ni—O bonding distances are within the expected ranges for Ni–Schiff base derivatives. The diimine bridge has a gauche conformation with the cyclohexyl ring almost coplanar with the NiN2O2 plane. The complex molecules pack in dimers with an Ni?Ni distance of 3.59 (1) Å and form a three‐dimensional structure displaying a herring‐bone configuration. Channels are occupied by solvent molecules, which are involved in C—H?O hydrogen bonds with the ligand O atoms. 相似文献
14.
Anthony Linden Andreas Gebert Heinz Heimgartner 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(6):764-766
The tetrathiane ring of the title compound, C26H16S4, has a chair conformation and the molecule has approximate C2 symmetry. Each of the two fluorene ring systems is virtually planar, with the ring planes intersecting at an angle of 67.58 (5)°. This novel compound has been formed as a side product from the treatment of 9H‐fluorene‐9‐thione with methyl N‐[(benzylidene)phenyl]glycinate in the presence of LiBr and 1,6‐diazabicyclo[5.4.0]undecane. 相似文献
15.
S. Thamotharan V. Parthasarathi S. Dubey D. P. Jindal Anthony Linden 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(2):o110-o112
In the title compound, C29H36O2, the outer cyclohexene ring of the steroid nucleus has a conformation that lies about half‐way between a half‐chair and an envelope, while the central and outer cyclohexane rings of the steroid nucleus have slightly distorted chair conformations. The steroidal cyclopentane ring adopts a 13β,14α‐half‐chair conformation. The benzylidene moiety has an E configuration with respect to the carbonyl group on the cyclopentane ring. The dihedral angle between the mean planes of the steroid nucleus and the benzylidene moiety is 35.54 (9)°. The packing of the molecules is assumed to be dictated mainly by weak intermolecular C—H⋯O interactions. 相似文献
16.
K. Ravikumar B. Sridhar M. Mahesh V. V. Narayana Reddy 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(5):o267-o269
8‐Chloro‐9‐fluoro‐5‐phenyl‐3,4,4a,5,6,10b‐hexahydro‐2H‐pyrano[3,2‐c]quinoline and 10‐chloro‐9‐fluoro‐5‐phenyl‐3,4,4a,5,6,10b‐hexahydro‐2H‐pyrano[3,2‐c]quinoline, both C18H17ClFNO, are diastereoisomers, formed as the result of the imino Diels–Alder reactions of N‐benzylideneanilines with 3,4‐dihydro‐2H‐pyran. The crystal structures reveal the stereochemistry of the pyran ring, which is endo/exo to the quinoline ring system formed in the cycloaddition step. In both structures, the pyran ring adopts a chair conformation, while the nitrogen‐containing heterocyclic ring prefers a half‐chair conformation. The structures differ essentially in the relative orientation of the ring junction H atoms. 相似文献
17.
Thierry Le Borgne Pierre Thury Michel Ephritikhine 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(1):m8-m9
The ligand 1,2,3,4‐tetramethyl‐5‐(2‐pyridyl)cyclopentadiene (cp*py) forms a dinuclear complex with UIV, i.e. di‐μ‐oxo‐bis{chloro(diethyl ether‐κO)[(η5,κN)‐1,2,3,4‐tetramethyl‐5‐(2‐pyridyl)cyclopentadienyl]uranium(IV)}, [U2Cl2O2(C14H16N)2(C4H10O)2], in which cp*py acts as a chelating ligand, being bound to the metal atom by the cyclopentadienyl unit and also by the N atom of the pyridyl ring. 相似文献
18.
Shi‐Ping Yang Xi‐Bin Yu Ji‐Guang Huang Han‐Hong Xu 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(7):o392-o393
The structure determination of the title compound, rotenone α‐oxime [systematic name: 1,2,12,12a‐tetrahydro‐8,9‐dimethoxy‐2‐(1‐methylethenyl)‐[1]benzopyrano[3,4‐b]furo[2,3‐h][1]benzopyran‐6(6H)‐one oxime], C23H23NO6, confirms that the molecule has an approximately V‐shaped structure. One of the rings has a typical cyclohexene‐like monoplanar conformation and the central ring adopts a 1,2‐diplanar conformation. 相似文献
19.
Peter G. Jones Jrg Hillmer Henning Hopf 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(5):o301-o304
The title isomers 4,16‐ (pseudo‐ortho), 4,15‐ (pseudo‐gem) and 4,12‐bis(methoxycarbonyl)[2.2]paracyclophane (pseudo‐para), C20H20O4, all show the typical structural features of [2.2]paracyclophanes (flattened boat conformation of the rings, lengthened single bonds in the bridges and narrow ring angles at the bridgehead atoms). The 4,12‐isomer displays crystallographic inversion symmetry. The carbonyl groups adopt a conformation in which they are directed away from the ring systems towards the nearest bridge; the corresponding angle at the ring substituent atom is widened. Crystal packing involves C—H?π interactions for the 4,15‐isomer and weak C—H?O hydrogen bonds for the other two isomers. 相似文献
20.
Smriti Khera Michael D. Carducci Jian‐Qiao Gu Barbara N. Timmermann 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(11):o773-o775
The structure of an iridolactone isolated from Valeriana laxiflora was established as (4R,4aR,6S,7S,7aS)‐6‐hydroxy‐7‐hydroxymethyl‐4‐methylperhydrocyclopenta[c]pyran‐1‐one chloroform solvate, C10H16O4·CHCl3. The two rings are cis‐fused. The δ‐lactone ring adopts a slightly twisted half‐chair conformation with approximate planarity of the lactone group and the cyclopentane ring adopts an envelope conformation. The hydroxy group, the hydroxymethyl group and the methyl group all have β orientations. The absolute configuration was determined using anomalous dispersion data enhanced by the adventitious inclusion of a chloroform solvent molecule. Hydrogen bonding, crystal packing and ring conformations are discussed in detail. 相似文献