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1.
Magnus Frnbck Lars Eriksson Gran Widmalm 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(6):700-701
The structure of the title compound, C28H38O18S, has been determined. The torsion angles of the glycosidic linkage in the non‐reducing disaccharide, ?H and ?H′, have values of 3 and 53°, respectively. The latter torsion angle is in agreement with the exo‐anomeric effect, whereas the former shows an eclipsed conformation. Both glycopyranosyl residues adopt a slightly distorted chair conformation. 相似文献
2.
Magnus Frnbck Lars Eriksson Gran Widmalm 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(3):o171-o173
The water content of the title compound, C13H24O10·3H2O, creates an extensive hydrogen‐bonding pattern, with all the hydroxyl groups of the disaccharide acting as hydrogen‐bond donors and acceptors. The water molecules are arranged in columns along the crystallographic b axis and form, together with one of the hydroxyl groups, infinite hydrogen‐bonded chains. The conformation of the disaccharide is described by glycosidic torsion angles of −38 and 18°. 相似文献
3.
Lars Eriksson Roland Stenutz Gran Widmalm 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(6):o328-o329
The overall conformation of the title compound, C13H24O10, is described by the glycosidic torsion angles ?H (H1g—C1g—O2r—C2r) and ψH (C1g—O2r—C2r—H2r), which have values of 13.6 and 16.1°, respectively. The former is significantly different from the value predicted by consideration of the exo‐anomeric effect (?H~ 60°) and from that in solution (?H~ 50°), as determined previously by NMR spectroscopy. An intramolecular O3r—H?O2g hydrogen bond may help to stabilize the conformation in the solid state. The orientation of the hydroxymethyl group of the glucose residue is gauche–gauche, with a torsion angle ω (O5g—C5g—C6g—O6g) of ?70.4 (4)°. Both pyranose rings are in their expected chair conformations, i.e.4C1 for d ‐glucose and 1C4 for l ‐rhamnose. 相似文献
4.
Yingxin Xiao Ronald J. Voll Damon R. Billodeaux Frank R. Fronczek Ezzat S. Younathan 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(5):582-583
The title compound, C20H22O6, has crystallographic twofold symmetry. The central six‐C‐atom chain has an extended conformation similar to that of d ‐mannitol, with two independent C—C—C—C torsion angles of 165.69 (14) and 177.60 (12)°. The 1,3‐dioxane ring has a chair conformation. All chiral centers have the R configuration. 相似文献
5.
Magnus Frnbck Lars Eriksson Gran Widmalm 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(2):o31-o32
The structure of the title compound, C13H24O10·H2O, is stabilized by hydrogen bonds situated adjacent to the glycoside linkage. A direct intramolecular hydrogen bond is present between the fucopyranosyl ring O atom and a glucopyranoside OH group, and a bridging water molecule mediates a hydrogen‐bond‐based interaction from a fucopyranosyl OH group to the methoxy O atom. The conformation of the disaccharide is described by the glycosidic torsion angles ϕH = −41° and ψH = −2°. 相似文献
6.
Qingfeng Pan Bruce C. Noll Anthony S. Serianni 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(12):o674-o677
Methyl α‐lactoside, C13H24O11, (I), is described by glycosidic torsion angles ϕ (O5gal—C1gal—O1gal—C4glc) and ψ (C1gal—O1gal—C4glc—C5glc), which have values of −93.52 (13) and −144.83 (11)°, respectively, where the ring atom numbering conforms to the convention in which C1 is the anomeric C atom and C6 is the exocyclic hydroxymethyl (–CH2OH) C atom in both residues. The linkage geometry is similar to that observed in methyl β‐lactoside methanol solvate, (II), in which ϕ is −88.4 (4)° and ψ is −161.3 (4)°. As in (II), an intermolecular O3glc—H⋯O5gal hydrogen bond is observed in (I). The hydroxymethyl group conformation in both residues is gauche–trans, with torsion angles ωgal (O5gal—C5gal—C6gal—O6gal) and ωglc (O5glc—C5glc—C6glc—O6glc) of 69.15 (13) and 72.55 (14)°, respectively. The latter torsion angle differs substantially from that found for (II) [−54.6 (2)°; gauche–gauche]. Cocrystallization of methanol, which is hydrogen bonded to O6glc in the crystal structure of (II), presumably affects the hydroxymethyl conformation in the Glc residue in (II). 相似文献
7.
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
8.
Judge Brown Diwakar M. Pawar Frank R. Fronczek Eric A. Noe 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(10):o628-o630
Cyclodecyl 4‐nitrophenylacetate, C18H25NO4, has its ten‐membered ring in the expected diamond‐lattice boat–chair–boat [2323] conformation, with the substituent 4‐nitrophenylacetoxy group in the BCB IIIe position. The ester unit has the expected Z conformation, with an O=C—O—C torsion angle of −0.3 (3)°, and the connection to the benzene ring is nearly perpendicular to the ester, with an O=C—C—C torsion angle of 85.5 (2)°. An intermolecular contact exists between the ester C atom and a nitro O atom, having a C⋯O distance of 2.909 (2) Å. 相似文献
9.
Wenhui Zhang Allen G. Oliver Henry M. Vu John G. Duman Anthony S. Serianni 《Acta Crystallographica. Section C, Structural Chemistry》2012,68(12):o502-o506
Methyl β‐D‐mannopyranosyl‐(1→4)‐β‐D‐xylopyranoside, C12H22O10, (I), crystallizes as colorless needles from water, with two crystallographically independent molecules, (IA) and (IB), comprising the asymmetric unit. The internal glycosidic linkage conformation in molecule (IA) is characterized by a ϕ′ torsion angle (O5′Man—C1′Man—O1′Man—C4Xyl; Man is mannose and Xyl is xylose) of −88.38 (17)° and a ψ′ torsion angle (C1′Man—O1′Man—C4Xyl—C5Xyl) of −149.22 (15)°, whereas the corresponding torsion angles in molecule (IB) are −89.82 (17) and −159.98 (14)°, respectively. Ring atom numbering conforms to the convention in which C1 denotes the anomeric C atom, and C5 and C6 denote the hydroxymethyl (–CH2OH) C atom in the β‐Xylp and β‐Manp residues, respectively. By comparison, the internal glycosidic linkage in the major disorder component of the structurally related disaccharide, methyl β‐D‐galactopyranosyl‐(1→4)‐β‐D‐xylopyranoside), (II) [Zhang, Oliver & Serriani (2012). Acta Cryst. C 68 , o7–o11], is characterized by ϕ′ = −85.7 (6)° and ψ′ = −141.6 (8)°. Inter‐residue hydrogen bonding is observed between atoms O3Xyl and O5′Man in both (IA) and (IB) [O3Xyl...O5′Man internuclear distances = 2.7268 (16) and 2.6920 (17) Å, respectively], analogous to the inter‐residue hydrogen bond detected between atoms O3Xyl and O5′Gal in (II). Exocyclic hydroxymethyl group conformation in the β‐Manp residue of (IA) is gauche–gauche, whereas that in the β‐Manp residue of (IB) is gauche–trans. 相似文献
10.
Dominik Winicker Michael Bolte 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(6):e271-e272
The title compound, C22H22O4, is the product of the Diels–Alder reaction of anthracene with fumaric acid diethyl ester. The molecular C2 symmetry is nearly fulfilled in the crystal. Only the terminal torsion angles about the O—CH2 groups show significant differences. 相似文献
11.
Wenhui Zhang Qingquan Wu Allen G. Oliver Anthony S. Serianni 《Acta Crystallographica. Section C, Structural Chemistry》2019,75(6):610-615
The crystal structure of methyl α‐d ‐mannopyranosyl‐(1→3)‐2‐O‐acetyl‐β‐d ‐mannopyranoside monohydrate, C15H26O12·H2O, ( II ), has been determined and the structural parameters for its constituent α‐d ‐mannopyranosyl residue compared with those for methyl α‐d ‐mannopyranoside. Mono‐O‐acetylation appears to promote the crystallization of ( II ), inferred from the difficulty in crystallizing methyl α‐d ‐mannopyranosyl‐(1→3)‐β‐d ‐mannopyranoside despite repeated attempts. The conformational properties of the O‐acetyl side chain in ( II ) are similar to those observed in recent studies of peracetylated mannose‐containing oligosaccharides, having a preferred geometry in which the C2—H2 bond eclipses the C=O bond of the acetyl group. The C2—O2 bond in ( II ) elongates by ~0.02 Å upon O‐acetylation. The phi (?) and psi (ψ) torsion angles that dictate the conformation of the internal O‐glycosidic linkage in ( II ) are similar to those determined recently in aqueous solution by NMR spectroscopy for unacetylated ( II ) using the statistical program MA′AT, with a greater disparity found for ψ (Δ = ~16°) than for ? (Δ = ~6°). 相似文献
12.
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
13.
Hussein Al‐Mughaid Katherine N. Robertson Ulrike Werner‐Zwanziger Michael D. Lumsden T. Stanley Cameron T. Bruce Grindley 《Acta Crystallographica. Section C, Structural Chemistry》2011,67(2):o60-o63
The 2‐propynyl group in the title compound, C17H22O10, adopts an exoanomeric conformation, with the acetylenic group gauche with respect to position C1. Comparison of 13C NMR chemical shifts from solution and the solid state suggest that the acetylenic group also adopts a conformation anti to C1 in solution. The pyranose ring adopts a 4C1 conformation. Of the three secondary O‐acetyl groups, that on position O4, flanked by two equatorial groups, adopts a syn conformation, in agreement with recent generalizations [González‐Outeiriño, Nasser & Anderson (2005). J. Org. Chem. 70 , 2486–2493]. The acetyl group on position O3 adopts a gauche conformation, also in agreement with the recent generalizations, but that on position O2 adopts a syn conformation, not in agreement with the recent generalizations. 相似文献
14.
Frank Seela Simone Budow Henning Eickmeier Hans Reuter 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(1):o54-o57
The title compound, 4‐amino‐1‐(2‐deoxy‐β‐d ‐erythropentofuranosyl)‐5‐(prop‐1‐ynyl)pyrimidin‐2(1H)‐one, C12H15N3O4, shows two conformations in the crystalline state which differ mainly in the glycosylic bond torsion angle and the sugar pucker. Both molecules exhibit an anti glycosylic bond conformation, with torsion angles χ = −135.0 (2) and −156.4 (2)° for molecules 1 and 2, respectively. The sugar moieties show a twisted C2′‐endo sugar pucker (S‐type), with P = 173.3 and 192.5° for molecules 1 and 2, respectively. The crystal structure is characterized by a three‐dimensional network that is stabilized by several intermolecular hydrogen bonds between the two conformers. 相似文献
15.
Barbara Piotrkowska Tadeusz Pooski Maria Gdaniec 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(12):o693-o696
The bis‐thionooxalamic acid esters trans‐(±)‐diethyl N,N′‐(cyclohexane‐1,2‐diyl)bis(2‐thiooxamate), C14H22N2O4S2, and (±)‐N,N′‐diethyl (1,2‐diphenylethane‐1,2‐diyl)bis(2‐thiooxamate), C22H24N2O4S2, both consist of conformationally flexible molecules which adopt similar conformations with approximate C2 rotational symmetry. The thioamide and ester parts of the thiooxamate group are significantly twisted along the central C—C bond, with the S=C—C=O torsion angles in the range 30.94 (19)–44.77 (19)°. The twisted s‐cis conformation of the thionooxamide groups facilitates assembly of molecules into a one‐dimensional polymeric structure via intermolecular three‐center C=S...NH...O=C hydrogen bonds and C—H...O interactions formed between molecules of the opposite chirality. 相似文献
16.
John F. Gallagher Claire M. Coleman Donal F. O'Shea 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(2):o149-o151
The molecule of the title compound, C19H27NO3, is essentially planar, with all non‐H atoms within 0.2 Å of the nine‐membered indole plane, except for the three tert‐butyl C atoms. The C5 pentyl chain is in an extended conformation, with three torsion angles of 179.95 (13), 179.65 (13) and −178.95 (15)° (the latter two angles include the C atoms of the C5 chain only). Three intramolecular C—H⋯Ozdbnd;C contacts are present (C⋯O < 3.05 Å and C—H⋯O > 115°), and an intermolecular C—H⋯Ozdbnd;C contact and π–π stacking complete the intermolecular interactions. 相似文献
17.
Peiwen Zhou James D. Fisher Richard J. Staples Ashwani Vij Nicholas R. Natale 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(9):1146-1147
The title compound, C14H21NO5, possesses an isoxazolyl group in the axial position of the 1,3‐dioxanyl ring. The two rings are rotated about the bond joining them such that the two C(methyl)—C(dioxanyl)—C—C torsion angles are 92.1 (2) and ?84.1 (2)°. In this conformation, neither the methyl nor ethoxycarbonyl substituents on the isoxazole are presented towards the dioxanyl chair. 相似文献
18.
Fiona Brady John F. Gallagher 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(11):1407-1410
The title compound, C17H15NO4, derived from l ‐tyrosine, crystallizes with three independent molecules which differ in the conformation of the asymmetric unit: the N—C—C—Cipso torsion angles are ?71.7 (5), ?63.6 (6) and ?52.5 (5)°, respectively. Deformations in the phenol ring hydroxy O—C—C angles of 116.5 (4)/123.9 (4), 121.7 (5)/118.1 (4) and 122.4 (5)/118.6 (5)°, respectively, result from their respective intermolecular hydrogen‐bonding environments. Intermolecular Oacid—H?O=Cindole, Ophenol—H?O—Hphenol and Ophenol—H?O=Cindole hydrogen bonds, with O?O distances in the range 2.607 (4)–2.809 (4) Å, are present in combination with C—H?O and C—H?πarene interactions. The primary hydrogen‐bonding systems assemble with graph sets R33(8) and R32(22). 相似文献
19.
Ying Fu Yin‐Xia He Hong‐Xia Hou Wen‐Bo Zhu Hu‐Lin Li Chao Wu Fang‐Yan Xian 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(3):282-284
2,2′‐Anhydro‐1‐(3′,5′‐di‐O‐acetyl‐β‐D‐arabinofuranosyl)uracil, C13H14N2O7, was obtained by refluxing 2′,3′‐O‐(methoxymethylene)uridine in acetic anhydride. The structure exhibits a nearly perfect C4′‐endo (4E) conformation. The best four‐atom plane of the five‐membered furanose ring is O—C—C—C, involving the C atoms of the fused five‐membered oxazolidine ring, and the torsion angle is only −0.4 (2)°. The oxazolidine ring is essentially coplanar with the six‐membered uracil ring [r.m.s. deviation = 0.012 (5) Å and dihedral angle = −3.2 (3)°]. The conformation at the exocyclic C—C bond is gauche–trans which is stabilized by various C—H...π and C—O...π interactions. 相似文献
20.
Gilles Muller Boris Schmidt Jan Jii
ek Jean‐Claude G. Bünzli Kurt J. Schenk 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(6):o353-o356
L4, or 3‐[2,6‐bis(diethylcarbamoyl)pyridin‐4‐yl]‐N‐(tert‐butoxycarbonyl)alanine methyl ester, C24H38N4O6, crystallizes in neat [010] laths stabilized by abundant intra‐ and intermolecular hydrogen bonds. The strongest of these form [010] chains of molecules, thus rationalizing the fastest growth direction, while the slowest direction coincides with the normal to the (110) layers, which are linked by very weak hydrogen bonds. There exist two independent molecules, the distances and bond angles of which differ in a random manner only. The torsion and dihedral angles, however, differ so as to achieve optimal packing. The influence of the chiral group in the 4‐position of the pyridine ring on the helical wrapping and on the ensuing diastereomeric induction is briefly discussed. 相似文献