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1.
Anthony Linden A. S. Muhammad Sofian C. Kuan Lee 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(12):o718-o720
At 160 K, one of the Cl atoms in the furanoid moiety of 3‐O‐acetyl‐1,6‐dichloro‐1,4,6‐trideoxy‐β‐d ‐fructofuranosyl 2,3,6‐tri‐O‐acetyl‐4‐chloro‐4‐deoxy‐α‐d ‐galactopyranoside, C20H27Cl3O11, is disordered over two orientations, which differ by a rotation of about 107° about the parent C—C bond. The conformation of the core of the molecule is very similar to that of 3‐O‐acetyl‐1,4,6‐trichloro‐1,4,6‐trideoxy‐β‐d ‐tagatofuranosyl 2,3,6‐tri‐O‐acetyl‐4‐chloro‐4‐deoxy‐α‐d ‐galactopyranoside, particularly with regard to the conformation about the glycosidic linkage. 相似文献
2.
Aleksandar Vinjevac Biserka Koji‐Prodi Marijana Vinkovi Kata Mlinari‐Majerski 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(6):o314-o316
The conformational features of the title compound, C28H44S6, are compared with previously reported analogous macrocycles. The type of substituent affects considerably the conformation of the macrocycle. A 1H NMR titration of the title compound with AgBF4 indicated the formation of the 1:1 complex, which was not crystallized. 相似文献
3.
Anthony Linden A. S. Muhammad Sofian C. Kuan Lee 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(12):o711-o714
At 160 K, the glucopyranosyl ring in 1,6‐dichloro‐1,6‐dideoxy‐β‐d ‐fructofuranosyl 4‐chloro‐4‐deoxy‐α‐d ‐glucopyranoside monohydrate, C12H19Cl3O8·H2O, has a near ideal 4C1 chair conformation, while the fructofuranosyl ring has a 4T3 conformation. The conformation of the sugar molecule is quite different to that of sucralose, particularly in the conformation about the glycosidic linkage, which affects the observed pattern of intramolecular hydrogen bonds. A complex series of intermolecular hydrogen bonds links the sugar and water molecules into an infinite three‐dimensional framework. 相似文献
4.
Reza‐Ali Fallahpour Anthony Linden 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(5):o283-o285
In the nearly planar title compound, C15H10IN3, the three pyridine rings exhibit transoid conformations about the interannular C—C bonds. Very weak C—H...N and C—H...I interactions link the molecules into ribbons. Significant π–π stacking between molecules from different ribbons completes a three‐dimensional framework of intermolecular interactions. Four different packing motifs are observed among the known structures of simple 4′‐substituted terpyridines. 相似文献
5.
G. Y. S. K. Swamy K. Ravikumar B. Sridhar I. Mahender K. V. N. S. Srinivas 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(8):o495-o497
The title compound [systematic name: 5‐hydroxy‐2‐(3‐hydroxy‐4,5‐dimethoxyphenyl)‐3,6,7‐trimethoxy‐4H‐chromen‐4‐one], C20H20O9, was isolated from the seeds of Cleom viscosa Linn. Two independent molecules (A and B) are present in the asymmetric unit with almost similar conformations. The dihedral angles between the fused chromene ring system and the benzene ring bonded to it in molecules A and B are 4.2 (1) and 12.7 (1)°, respectively. The hydroxy O atoms are involved in intramolecular hydrogen bonding. The molecules are linked by C—H⋯O and O—H⋯O interactions into chains of edge‐fused R33(22) rings. Aromatic π–π and weak C—H⋯π(arene) interactions are also observed. 相似文献
6.
Xiaoming Liu Colin A. Kilner Mark Thornton‐Pett Malcolm A. Halcrow 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(9):1142-1143
The title compound, C17H13N3, is a versatile precursor for polymeric terpyridine derivatives and their metal complexes. The molecule has transoid and near‐coplanar pyridine rings. However, the vinyl group is forced out of the plane of the terpyridyl moiety by a close H?H contact. 相似文献
7.
8.
Fabían Orozco Braulio Insuasty John N. Low Justo Cobo Christopher Glidewell 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(3):o162-o165
The title compound, C36H16O6, (I), was obtained as a new and unexpected oxidation product of 1,2′‐biindene‐1′,3,3′(2H)‐trione. The molecules of (I) exhibit approximate, but noncrystallographic, twofold rotation symmetry and the central ring of the fused pentacyclic portion is distinctly puckered, with a conformation intermediate between half‐chair and screw‐boat. Six independent C—H...O hydrogen bonds link the molecules into a three‐dimensional framework structure of considerable complexity. Comparisons are drawn between the crystal structure of (I) and those of several simpler analogues, which show wide variation in their patterns of supramolecular aggregation. 相似文献
9.
R. Malathi S. S. Rajan Geetha Gopalakrishnan G. Suresh 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(11):o681-o682
The title compound, methyl (2aS,3R,5R,5aS,6S,6aS,8R,9aS,10aR,10bR,10cS)‐8‐(3‐furyl)‐2a,4,5,5a,6,6a,8,9,9a,10a,10b,10c‐dodecahydro‐3‐hydroxy‐2a,5a,6a,7‐tetramethyl‐5‐(3‐methylbut‐2‐enoyloxy)‐2H,3H‐cyclopenta[4′,5′]furo[2′,3′:6,5]benzo[cd]isobenzofuran‐6‐acetate, C32H42O8, was isolated from uncrushed green leaves of Azadirachta indica A. Juss (neem) and has been found to possess antifeedant activity against Spodptera litura. The conformations of the functional groups are similar to those of 3‐desacetylsalannin, which was isolated from neem kernels. The molecules are linked into chains by intermolecular O—H?O hydrogen bonds. 相似文献
10.
A. Subbiah Pandi S. Banumathi D. Velmurugan S. Shanmuga Sundara Raj Hoong‐Kun Fun S. Manikandan 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(7):819-820
In the title compound, C24H18ClNO2, the phenyl ring and the tetralone moiety are approximately orthogonal to the isoxazoline ring. The isoxazoline ring adopts an envelope conformation, while the cyclohexenone ring of the tetralone moiety has an intermediate sofa/half‐chair conformation. In this structure, one C—H?N intermolecular and two C—H?O intramolecular hydrogen bonds occur; the H?A distances are 2.60, and 2.35 and 2.57 Å, respectively. The molecules are held together by an intermolecular C—H?N hydrogen bond, forming a one‐dimensional chain along the [100] direction. 相似文献
11.
Bar Tercan Tuncer Hkelek Hakan Dal Yasemin Süzen Zeynel Kl 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(9):o639-o641
The title compound, C13H12Cl4N5OP3, is a phosphazene derivative with a bulky substituted spirocyclic ring. The C3NPO spirocyclic ring has a twist‐boat conformation, while the phosphazene ring has a very flattened boat conformation. 相似文献
12.
SasankSekhar Mohanty Peter Uebelhart ConradHans Eugster 《Helvetica chimica acta》2000,83(8):2036-2053
Incubation of deuteriated precursors in cultures of Flavobacterium produced specifically deuteriated carotenoids. Analysis of these led to several conclusions: i) Lycopene is a direct precursor of β,β‐carotene. ii) Its terminal Me groups retain their integrity during cyclization: there is a stereospecific folding of the 1,5‐diene. The Me(16,16′) groups of lycopene become the Me(16,16′) of β,β‐carotene. Consequently, the folding must follow the C2(E,E) mode. iii) Incorporation of deuterium was sufficiently extensive to permit CD measurements on the isolated β,β‐carotene, allowing its centers of chirality to be assigned as (1S,1′S). iv) The same chirality resulted from incorporation of [2H3]mevalonate into zeaxanthin. The syntheses of specifically deuteriated [2H3]GPP, [2H3]FPP, and [2H3]GG are described. 相似文献
13.
Tomohiro Matsumoto Taisuke Matsumoto Masataka Watanabe Shuntaro Mataka Thies Thiemann 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(7):o501-o502
In the title compound, C21H25N3O, the six‐membered ring that is fused to two other six‐membered rings in the estrane moiety adopts an envelope conformation. The compound shows intermolecular hydrogen bonding of the amine group to an N atom of the pyrimidine moiety, as well as weak intermolecular interactions involving H atoms in the hydrophobic residue of the molecule. 相似文献
14.
Dewey H. Barich Mark T. Zell Douglas R. Powell Eric J. Munson 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(4):o261-o262
The title compounds (both C9H10O4) have nearly planar structures, and the methyl and/or carboxylic acid groups lie out of the molecular plane, as dictated by steric interactions. 2,5‐Dimethoxybenzoic acid (2,5‐DMBA) forms an unusual intramolecular hydrogen bond between the carboxylic acid group and the O atom of the methoxy group in the 2‐position [O⋯O = 2.547 (2) Å and O—H⋯O = 154 (3)°]. 2,4‐DMBA forms a typical hydrogen‐bond dimer with a neighboring molecule. 相似文献
15.
Isabelle Boyer Sophie Quillard Benoit Corraze Philippe Deniard Michel Evain 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(4):e159-e159
A new triclinic polymorphic form of N,N′‐diphenyl‐1,4‐phenylenediamine (C6H5NHC6H4NHC6H5) has been obtained through appropriate recrystallization of the orthorhombic form. It crystallized in the centrosymmetric space group P, with two half molecules as the asymmetric unit. 相似文献
16.
John Reglinski Michelle K. Taylor Alan R. Kennedy 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(3):o169-o172
We have isolated and crystallographically characterized the three homologous compounds N,N′‐bis(2‐methoxybenzylidene)ethane‐1,2‐diamine (MeSalen), C18H20N2O2, N,N′‐bis(2‐methoxybenzylidene)propane‐1,3‐diamine (MeSalpr), C19H22N2O2, and N,N′‐bis(2‐methoxybenzylidene)butane‐1,4‐diamine (MeSalbu), C20H24N2O2. In contrast with MeSalpr, the molecules of MeSalen and MeSalbu, which have an even number of methylene units, have crystallographic symmetry. Comparing these methoxy‐substituted species with their hydroxy equivalents shows that the aryl rings rotate upon removal of the O—H⋯N hydrogen bonds. The packing of MeSalen and MeSalpr is controlled by C—H⋯π interactions, whereas that of MeSalbu has only van der Waals contacts. 相似文献
17.
Jaromír Marek Kamila Lunerov Jaromír Touek Vclav Suchý Radek Marek 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(6):o386-o389
The crystal structures of 2′,4′‐dihydroxy‐3‐methoxy‐α,β‐dihydrochalcone, C16H16O4, and 2′,4‐dihydroxy‐α,β‐dihydrochalcone, C15H14O3, have been determined. In both compounds, the structure consists of two nearly planar six‐membered aromatic rings connected by a propanal chain, which is bent in the methoxy compound and almost straight in the other compound. In the crystal structures, the molecular units of both compounds are linked by O—H⋯O hydrogen bonds to form infinite one‐dimensional chains. Hydrogen bonds and C—H⋯O contacts in the crystal structures were studied by topological analysis of charge density based on Hartree–Fock calculations. Almost all of the investigated C—H⋯O contacts should be characterized as weak hydrogen bonds. 相似文献
18.
Krzysztof Ejsmont Janusz Kyzio Ewa Nowakowska Jacek Zaleski 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(1):93-94
The title compound, C23H28O2, was obtained from the reaction of acetone with meta‐cresol. The molecular structure consists of two identical subunits which are nearly perpendicular to each other. The oxygen‐containing rings are not planar and the molecule is chiral. The crystal structure consists of chains of molecules of the same chirality arranged along the [010] axis. 相似文献
19.
The preparation of 1′-and 3′-amino-5′,6′,7′,8′-tetrahydro-2′-acetonaphthones (IIIa and IIIb) is described, by reduction of the low temperature nitration products of 5′,6′,7′,8′-tetrahydro-2′-acetonaphtone (I). The structures of the nitro isomers (IIa and IIb), and the reduction products, IIIa and IIIb, were elucidated spectroscopically. By known reactions, a series of new heterocyclic compounds prepared from the o-aminoketones, IIIa and IIIb, resulted in two series of new heterocyclic compounds. 相似文献
20.
Libin Gao 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(6):634-637
The title compound, C58H64S8, has been prepared by Pd‐catalysed direct C—H arylation of tetrathienonaphthalene (TTN) with 5‐hexyl‐2‐iodothiophene and recrystallized by slow evaporation from dichloromethane. The crystal structure shows a completely planar geometry of the TTN core, crystallizing in the monoclinic space group P21/c. The structure consists of slipped π‐stacks and the interfacial distance between the mean planes of the TTN cores is 3.456 (5) Å, which is slightly larger than that of the comparable derivative of tetrathienoanthracene (TTA) with 2‐hexylthiophene groups. The packing in the two structures is greatly influenced by both the aromatic core of the structure and the alkyl side chains. 相似文献