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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.
Anthony Linden C. Kuan Lee A. S. Muhammad Sofian 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(9):1098-1100
At 160 K, the glucopyranosyl ring of the title compound, C20H28ClIO13, has a near‐ideal 4C1 conformation and the fructofuranosyl ring has a twist 4T3 conformation. The two hydroxy groups are involved in intra‐ and intermolecular hydrogen bonds, with the latter interactions linking the molecules into infinite one‐dimensional chains. The absolute configuration of the molecule has been determined. 相似文献
3.
Shusheng Zhang Zhongwei Wang Ming Li Kui Jiao Ibrahim Abdul Razak S. Shanmuga Sundara Raj Hoong‐Kun Fun 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(5):566-568
In both the title structures, O‐ethyl N‐(2,3,4,6‐tetra‐O‐acetyl‐β‐d ‐glucopyranosyl)thiocarbamate, C17H25NO10S, and O‐methyl N‐(2,3,4,6‐tetra‐O‐acetyl‐β‐d ‐glucopyranosyl)thiocarbamate, C16H23NO10S, the hexopyranosyl ring adopts the 4C1 conformation. All the ring substituents are in equatorial positions. The acetoxymethyl group is in a gauche–gauche conformation. The S atom is in a synperiplanar conformation, while the C—N—C—O linkage is antiperiplanar. N—H?O intermolecular hydrogen bonds link the molecules into infinite chains and these are connected by C—H?O interactions. 相似文献
4.
Frank Seela Yang He Henning Eickmeier 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(4):o194-o196
In the title compound, 3‐amino‐2‐(2‐deoxy‐β‐d ‐erythro‐pentofuranosyl)‐6‐methyl‐1,2,4‐triazin‐5(2H)‐one, C9H14N4O4, the conformation of the N‐glycosidic bond is high‐anti and the 2‐deoxyribofuranosyl moiety adopts a North sugar pucker (2T3). The orientation of the exocyclic C—C bond between the –CH2OH group and the five‐membered ring is ap (gauche, trans). The crystal packing is such that the nucleobases lie parallel to the ac plane; the planes are connected via hydrogen bonds involving the five‐membered ring. 相似文献
5.
Davide Viterbo Marco Milanesio Ramn Poms Hernndez Chryslaine Rodríguez Tanty Ivan Cols Gonzlez Marquiza Sabln Carrazana Julio Duque Rodríguez 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(5):580-581
The title compound, 1‐(2′,3′‐dideoxy‐β‐d ‐glycero‐pent‐2‐enofuranosyl)thymine 1‐methyl‐2‐pyrrolidone solvate, C10H12N2O4·C5H9NO, is an NMPO solvate of the anti‐AIDS agent D4T. In its crystal structure, both the pyrimidine and the furanose rings are planar and approximately perpendicular [82.1 (4)°]. The value of the torsion angle defining the orientation of the thymine with respect to the joined furane, χ = ?100.8 (4)°, and that of the torsion angle giving the orientation of the hydroxyl group linked to the furane ring, γ = 52.9 (5)°, show that the glycosylic link adopts the so‐called high‐anti conformation and the 5′‐hydroxyl group is in the +sc position. The NMPO solvate is linked to the nucleoside through a fairly strong hydrogen bond. 相似文献
6.
Frank Seela Yang He Hans Reuter Eva‐Maria Heithoff 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(8):989-991
In the title compound, 2‐amino‐1‐(2‐deoxy‐β‐d ‐erythro‐pentofuranosyl)‐5‐methylpyrimidin‐4(1H)‐one, C10H15N3O4, the conformation of the N‐glycosidic bond is syn and the 2‐deoxyribofuranose moiety adopts an unusual OT1 sugar pucker. The orientation of the exocyclic C4′—C5′ bond is +sc (+gauche). 相似文献
7.
Frank Seela Matthias Zulauf Hans Reuter Guido Kastner 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(4):489-491
The isomorphous structures of the title molecules, 4‐amino‐1‐(2‐deoxy‐β‐d ‐erythro‐pentofuranosyl)‐3‐iodo‐1H‐pyrazolo‐[3,4‐d]pyrimidine, (I), C10H12IN5O3, and 4‐amino‐3‐bromo‐1‐(2‐deoxy‐β‐d ‐erythro‐pentofuranosyl)‐1H‐pyrazolo[3,4‐d]pyrimidine, (II), C10H12BrN5O3, have been determined. The sugar puckering of both compounds is C1′‐endo (1′E). The N‐glycosidic bond torsion angle χ1 is in the high‐anti range [?73.2 (4)° for (I) and ?74.1 (4)° for (II)] and the crystal structure is stabilized by hydrogen bonds. 相似文献
8.
Lars Eriksson Roland Stenutz Gran Widmalm 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(6):702-704
The crystal structure of methyl 4‐O‐β‐l ‐fucopyranosyl α‐d ‐glucopyranoside hemihydrate C13H24O10·0.5H2O is organized in sheets with antiparallel strands, where hydrophobic interaction accounts for partial stabilization. Infinite hydrogen‐bonding networks are observed within each layer as well as between layers; some of these hydrogen bonds are mediated by water molecules. The conformation of the disaccharide is described by the glycosidic torsion angles: ?H = ?6.1° and ψH = 34.3°. The global energy minimum conformation as calculated by molecular mechanics in vacuo has ?H = ?58° and ψH = ?20°. Thus, quite substantial changes are observed between the in vacuo structure and the crystal structure with its infinite hydrogen‐bonding networks. 相似文献
9.
Frank Seela Yunlong Zhang Kuiying Xu Henning Eickmeier 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(1):o60-o62
In the title compound, 4‐amino‐1‐(2‐deoxy‐β‐d ‐eythro‐pentofuranosyl)‐3‐vinyl‐1H‐pyrazolo[3,4‐d]pyrimidine monohydrate, C12H15N5O3·H2O, the conformation of the glycosyl bond is anti. The furanose moiety is in an S conformation with an unsymmetrical twist, and the conformation at the exocyclic C—C(OH) bond is +sc (gauche, gauche). The vinyl side chain is bent out of the heterocyclic ring plane by 147.5 (5)°. The three‐dimensional packing is stabilized by O—H·O, O—H·N and N—H·O hydrogen bonds. 相似文献
10.
Junlin He Frank Seela Henning Eickmeier Hans Reuter 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(10):o593-o595
In the title regioisomeric nucleosides, alternatively called 1‐(2‐deoxy‐β‐d ‐erythro‐furanosyl)‐1H‐pyrazolo[3,4‐d]pyrimidine, C10H12N4O3, (II), and 2‐(2‐deoxy‐β‐d ‐erythro‐furanosyl)‐2H‐pyrazolo[3,4‐d]pyrimidine, C10H12N4O3, (III), the conformations of the glycosylic bonds are anti [?100.4 (2)° for (II) and 15.0 (2)° for (III)]. Both nucleosides adopt an S‐type sugar pucker, which is C2′‐endo‐C3′‐exo (2T3) for (II) and 3′‐exo (between 3E and 4T3) for (III). 相似文献
11.
Anthony Linden C. Kuan Lee A. S. Muhammad Sofian 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(11):1363-1366
At 160 K, the structure of 4-bromo-4-deoxysucrose, C12H21BrO10, is very similar to that of sucrose, particularly with respect to the conformation of the glycosidic linkage. As in sucrose, an intramolecular hydrogen bond exists between the glucopyranosyl and the fructofuranosyl rings. Conversely, the structure of 1′,6′-dibromo-4-fluoro-4,1′,6′-trideoxysucrose monohydrate, C12H19Br2FO8·H2O, shows large conformational differences when compared with the structures of both sucrose and sucralose. This compound does not exhibit any intramolecular hydrogen bonds. In each compound, a complex series of intermolecular hydrogen bonds link the molecules into an infinite three-dimensional framework. The absolute configuration of each molecule has been determined. 相似文献
12.
Rubn A. Toscano Emma Maldonado Alfredo Ortega Jorge Crdenas 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(7):846-847
The absolute configuration of the neoclerodane glycoside amarisolide, presented here as the monohydrate, C26H36O9·H2O, has been determined by association with the known configuration of the glucose moiety. Its structure was established as 2β‐(O‐β‐d ‐glucopyranosyl)neocleroda‐3,13(16),14‐trien‐15,16‐epoxy‐18,19‐olide. Extensive hydrogen bonding among the hydroxyl groups of the sugar moiety forms layers which are interconnected by water molecules. 相似文献
13.
Yang He Frank Seela Hans Reuter Eva‐Maria Heithoff 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(5):660-662
In the title compound, 4‐amino‐1‐(2‐deoxy‐β‐d ‐erythro‐pentofuranosyl)‐1H‐benzotriazole, C11H14N4O3, the conformation of the N‐glycosidic bond is in the high‐anti range [χ = ?77.1 (4)°] and the 2′‐deoxyribofuranose moiety adopts a 2′‐endo (2E) sugar puckering. The 5′‐hydroxyl group is disordered and has conformations ap with γ = 171.1 (3)° [occupation of 61.4 (3)%] and +sc with γ = 52.4 (6)° [occupation of 38.6 (3)%]. The nucleobases are stacked in the crystal state. 相似文献
14.
Frank Seela Helmut Rosemeyer Alexander Melenewski Eva‐Maria Heithoff Henning Eickmeier Hans Reuter 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(3):o142-o144
In the monohydrate of 2‐amino‐8‐(2‐deoxy‐α‐d ‐erythro‐pentofuranosyl)‐8H‐imidazo[1,2‐a][1,3,5]triazin‐4‐one, C10H13N5O4·H2O, denoted (I) or αZd, the conformation of the N‐glycosylic bond is in the high‐anti range [χ = 87.5 (3)°]. The 2′‐deoxyribofuranose moiety adopts a C2′‐endo,C3′‐exo(2′T3′) sugar puckering (S‐type sugar) and the conformation at the C4′—C5′ bond is ?sc (trans). 相似文献
15.
Jan W. Bats Uwe Parsch Joachim W. Engels 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(9):1129-1131
Crystals of 4,2′‐anhydro‐5‐(β‐d ‐arabinofuranosyl)uracil, (I), obtained from an aqueous solution, were characterized as the dihydrate, C9H10N2O5·2H2O, (Ia). In air, these crystals slowly transform to the monohydrate, C9H10N2O5·H2O, (Ib), but remain crystalline. The solid‐state transformation proceeds with the loss of one water molecule and a rearrangement of hydrogen‐bonded layers of molecules. The furanose ring in (I) has an approximate C4′‐exo,O4′‐endo twist conformation. The central five‐membered ring is slightly puckered. The uracil group is planar within experimental uncertainty. 相似文献
16.
Cheravakkattu G. Suresh Bindu Ravindran K. Narasimha Rao Tanmaya Pathak 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(8):1030-1032
The title compounds, the α and β anomers of methyl 2‐(N‐benzylamino)‐2,3‐dideoxy‐4,6‐O‐phenylmethylene‐3‐C‐phenylsulfonyl‐d ‐glucopyranoside, C27H29NO6S, belong to the class of deoxyamino‐sugars prepared by the addition of amines at C2. The endocyclic bond lengths of the pyranose ring in the α anomer are shorter than the corresponding bonds in the β anomer. The pyranose ring is in the chair form in the former, while it is in the boat form in the latter. These observed differences could be attributed to the C2 substitution of a bulky group. The phenylsulfonyl and benzylamino groups are in equatorial positions in the α anomer, while the benzylamino group is axial in the β anomer. 相似文献
17.
Marco Brito‐Arias Enrique Durn‐Pramo Ignasi Mata Elies Molins 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(9):o537-o539
The syntheses and X‐ray analyses of two fucopyranosides, the monosaccharide benzyl 3,4‐di‐O‐acetyl‐2‐hydroxy‐β‐d ‐fucopyranoside, C17H22O7, and the disaccharide 1‐benzyl O‐(2,3‐di‐O‐acetyl‐4,6‐O‐benzylidene‐β‐d ‐glucopyranosyl)‐(12)‐3,4‐O‐isopropylidene‐β‐d ‐fucopyranoside, C33H40O12, are described. The different substituents induce small conformational changes on the fucopyranoside ring. However, the conformation of the benzyl group varies from (+)gauche for the monosaccharide to synperiplanar for the disaccharide. 相似文献
18.
Wenqing Lin Frank Seela Henning Eickmeier Hans Reuter 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(8):o566-o568
In the tricyclic nucleoside 7‐(β‐d ‐ribofuranosyl)‐7H‐imidazo[1,2‐c]pyrazolo[4,3‐e][1,2,3]triazine, C11H12N6O4, the conformation of the N‐glycosyl bond is intermediate between anti and high anti [χ = −103.5 (3)°]. The ribofuranose moiety adopts a 3T2 sugar pucker (S‐type sugar) and the conformation at the exocyclic C—C bond is ap (gauche–trans). Molecules of the title compound form a three‐dimensional network via three medium–strong intermolecular hydrogen bonds (one O—H⋯N and two O—H⋯O bonds). 相似文献
19.
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
20.
Frank Seela Padmaja Chittepu Junlin He Henning Eickmeier 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(12):o884-o886
In the title compound, 2‐(2‐deoxy‐2‐fluoro‐β‐d ‐arabinofuranosyl)‐1,2,4‐triazine‐3,5(2H,4H)‐dione, C8H10FN3O5, the torsion angle of the N‐glycosylic bond is anti [χ = −125.37 (13)°]. The furanose moiety adopts the N‐type sugar pucker (3T2), with P = 359.2° and τm = 31.4°. The conformation around the C4′—C5′ bond is antiperiplanar (trans), with a torsion angle γ of 177.00 (11)°. A network is formed via hydrogen bonds from the nucleobases to the sugar residues, as well as through hydrogen bonds between the sugar moieties. 相似文献