In the crystal structure of the title compound, C27H27NO5S, the pyranose ring adopts a 4
1 chair conformation with puckering parameters Q = 0.639 (2) Å, θ = 174.11 (18) and ϕ = 256 (2)°. The presence of the 2,3-trans-oxazolidinone fixes the conformation of the pyranose ring. The phenyl group attached to the S atom and the benzyl group bonding to the N atom are each disordered over two positions with site occupancies of 0.624 (3):0.376 (3) and 0.526 (3):0.474 (3), respectively. An intermolecular O—H⋯O hydrogen bond is observed.
4-Deoxy-4-fluoro-β-d-glucopyranose, C6H11FO5, (I), crystallizes from water at room temperature in a slightly distorted 4
1 chair conformation. The observed chair distortion differs from that observed in β-d-glucopyranose [Kouwijzer, van Eijck, Kooijman & Kroon (1995 ▶). Acta Cryst. B51, 209–220], (II), with the former skewed toward a B
C3,O5 (boat) conformer and the latter toward an O5
C2 (twist–boat) conformer, based on Cremer–Pople analysis. The exocyclic hydroxymethyl group conformations in (I) and (II) are similar; in both cases, the O—C—C—O torsion angle is ∼−60° (gg conformer). Intermolecular hydrogen bonding in the crystal structures of (I) and (II) is conserved in that identical patterns of donors and acceptors are observed for the exocyclic substituents and the ring O atom of each monosaccharide. Inspection of the crystal packing structures of (I) and (II) reveals an essentially identical packing configuration.
The title compound, C22H22N2O10, was prepared by the glycosidation method through nitrite displacement on substituted nitrophthalonitrile. The molecule contains a benzene ring, two nitrile groups and an acetyl-protected d-glucose fragment which adopts a chair conformation. The absolute configuration was determined by the use of d-glucose as starting material. All substituents of the protected sugar are in equatorial positions, with the exclusive presence of the α-anomer. The crystal packing is stabilized by C—H⋯O and C—H⋯N hydrogen-bonding interactions.
The title compound, C13H24O10·4H2O, is the methyl glycoside of a disaccharide structural element present in the backbone of the capsular polysaccharide from Klebsiella K1, which contains only three sugars and a substituent in the polysaccharide repeating unit. The conformation of the title disaccharide is described by the glycosidic torsion angles ϕH = 51.1 (1)° and ψH = 25.8 (1)°. In the crystal, a number of O—H⋯O hydrogen bonds link the methyl glycoside and water molecules, forming a three-dimensional network. One water molecule is disordered over two positions with occupancies of 0.748 (4) and 0.252 (4).
In the title compound, C30H31NO6S, the plane of the N-phthalimido group is nearly orthogonal to the least-squares plane of the sugar ring (defined by atoms C2, C3, C5 and O5 using standard glucose nomenclature), making a dihedral angle of 72.8 (1)°. The thioethyl group has the exo-anomeric conformation. The hydroxy group forms an intermolecular hydrogen bond to the O atom in the sugar ring, generating  chains. There are four close π–π contacts with centroid–centroid distances less than 4.0 Å, all with dihedral angles between the interacting π systems of only ≃ 8°, supporting energetically favourable stacking interactions.
In the title compound, C23H23NO6S, the plane of the N-phthalimido group makes a dihedral angle of 67.4 (1)° with the least square plane of the sugar ring defined by the C2, C3, C5 and O5 atoms using standard glucose nomenclature. The thioethyl group has the exo-anomeric conformation. In the crystal, intermolecular hydrogen bonds involving the hydroxy groups and the carbonyl O atoms of adjacent N-phthalimido groups form chains parallel to the b axis. The chains are further stabilized by C—H⋯π interactions.
The crystal structure of the title compound, C28H38O11, solved and refined against synchrotron diffraction data, contains two formula units in the asymmetric unit. In both molecules, the dihydropyran ring along with its methyl substituents is disordered and adopts two alternative half-chair conformations. The occupancy of the major conformers of the two molecules refined to 0.858 (5) and 0.523 (5).
In the crystal structure of the title compound, C24H27NO11, a substituted tetraacetyl glucopyranoside derivative, weak intermolecular C—H⋯O hydrogen bonds link the molecules into ribbons propagated in . The d configuration has been attributed on the basis of the synthesis and the β anomer has been determined from the structure.
In the title compound, C30H33BrO6, the pyranose ring adopts a chair conformation. Two of the O-benzyl phenyl rings lie almost perpendicular to C/C/C/O plane formed by the ring atoms not attached to these O-benzyl phenyl rings, and form dihedral angles of 85.1 (2) and 64.6 (2)°, while the third O-benzyl phenyl ring is twisted so that it makes a dihedral angle 34.9 (2)° to this C/C/C/O plane. This twist is ascribed to the formation of an S(8) loop stabilized by a weak intramolecular C—H⋯O hydrogen bond.
The title compound, C13H24O11·4H2O, forms extended hydrogen-bonded networks. These are present between disaccharides, but not as inter-residue hydrogen bonds, as well as to water molecules that in addition form an intermolecular chain of hydrogen bonds. The conformation of the disaccharide is described by the glycosidic torsion angles ϕH = −34° and ψH = −5°. Macroscopically, the disaccharide was observed to be hygroscopic.
In the title compound, C14H25NO11·2H2O, the primary hydroxyl group connected to the anomeric C atom of the N-acetyl-β-d-glucopyranose residue exhibits positional disorder, with occupancy factors for the α and β anomers of 0.77 and 0.23, respectively. The two torsion angles (Φ and Ψ) and the bridge angle (τ) that describe conformation of the glycosidic linkage between the galactopyranose and glucopyranose rings are Φ = −81.6 (3)°, Ψ = 118.1 (2)° and τ = 115.2 (2)°. Two water molecules stabilize the molecular packing by forming hydrogen bonds with the saccharide residues.
Molecules of the title compound, C24H28O12, are linked by intermolecular C—H⋯O hydrogen bonds. Bond lengths and angles are normal.
The asymmetric unit of the title compound, C24H21FN2O5S, consists of two crystallographically independent molecules. In each molecule, the central dihydropyrimidine ring is significantly puckered and adopts a conformation which is best described as an intermediate between a boat and a screw boat. The least-squares planes of the dihydropyrimidine rings are almost coplanar with the fluoro-substituted benzene rings, making dihedral angles of 9.04 (7) and 6.68 (7)°, and almost perpendicular to the methoxy-substituted benzene rings with dihedral angles of 89.23 (7) and 88.30 (7)°. In the molecular structure, S(6) ring motifs are formed by C—H⋯O and C—H⋯S hydrogen bonds. In the crystal, molecules are linked into a three-dimensional network by intermolecular C—H⋯O and C—H⋯F hydrogen bonds. The crystal structure is further stabilized by a C—H⋯π interaction.
The title compound, C21H30O6, a natural ent-kaurane diterpenoid, was obtained from the medicinal plant Isodon serra. The five rings in the molecule exhibit the expected cis and trans junctions. The three six-membered rings adopt chair, twist-boat and boat conformations, while two five-membered rings adopt envelope conformations. There are two molecules in the asymmetric unit, related by a non-crystallographic twofold screw axis; the main difference is in the different degrees of distortion of ring B. In the crystal, the molecules are linked by intermolecular O—H⋯O hydrogen bonds, forming chains along the b axis.
The asymmetric unit of the title compound, [Co(C23H28N2O4)(C9H9O3)]·C2H5OH·H2O, comprises one complex molecule, a water molecule of crystallization and an ethanol molecule of crystallization, which is disordered over two positions with a ratio of refined site occupancies of 0.567 (10):0.433 (10). The CoIII ion is in a slightly distorted octahedral geometry involving an N2O2 atom set of the tetradenate Schiff base ligand and two O atoms of 2-ethoxy-6-formylphenolate. The H atoms of the water molecule act as donors in the formation of bifurcated intermolecular O—H⋯(O,O) hydrogen bonds with the O atoms of the hydroxy and ethoxy groups with R
2(5) ring motifs, which may influence the molecular conformation. The crystal structure is further stabilized by intermolecular O—H⋯O and C—H⋯O interactions.
In the title salt, C37H51N2O10
+·Br−, the 1,4-dihydropyridine (1,4-DHP) ring adopts a slighly puckered boat conformation. The N and opposite C atoms deviate from the least-squares plane calculated through the four other ring atoms by 0.068 (5) and 0.224 (5) Å, respectively. The orientation of both C=O groups is similar (cis with respect to the double bonds of 1,4-DHP. The pyridinium ring has an axial orientation with respect to the1,4-DHP ring and is almost perpendicular to the least-squares plane of the 1,4-DHP ring, making a dihedral angle of 89.2 (3)°. The molecule has a compact shape due to the parallel orientation of the long-chain substituents. One of the butoxy groups was fond to be disordered (occupancy ratio 0.70:0.30). In the crystal, the bromide anion accepts a weak hydrogen bond from the N—H group of a neighboring 1,4-DHP ring.
The title compound, C22H25F5N4O9, is a stable pentafluorophenyl ester intermediate in the synthesis of novel homo-oligomeric structures containing branched carbon chains. The structure is epimeric to the previously characterized dimeric pentafluorophenyl ester with stereochemistry (3R,4R,5R), which was synthesized using d-ribose as starting material. The crystal structure of the title molecule removes any ambiguities arising from the relative stereochemistries of the six chiral centres. Two hydrogen bonds, bifurcating from the NH group, stabilize the crystal: one intramolecular and one intermolecular, both involving O atoms of the methoxy groups. The asymmetric unit contains two independent molecules not related by any pseudo-symmetry operators. The major conformational differences are localized, leading to one molecule being extended compared to the other. The collected crystal was twinned (twin ratio is 0.939:0.061), and the azide group is positionally disordered over two positions in one molecule [occupancy ratio 0.511 (18):0.489 (18)].
The crystal of the isomorphous anhydrous ammonium salts of phenoxyacetic acid and (4-fluorophenoxy)acetic acid and that of the hemihydrate ammonium salt of 4-chloro-2-methylphenoxy)acetic acid show two-dimensional layered structures based on conjoined cyclic hydrogen-bonded motifs.
The structures of the ammonium salts of phenoxyacetic acid, NH4
−, (I), (4-fluorophenoxy)acetic acid, NH4
−, (II), and the herbicidally active (4-chloro-2-methylphenoxy)acetic acid (MCPA), NH4
−·0.5H2O, (III) have been determined. All have two-dimensional layered structures based on inter-species ammonium N—H⋯O hydrogen-bonding associations, which give core substructures consisting primarily of conjoined cyclic motifs. The crystals of (I) and (II) are isomorphous with the core comprising R
2(4) and centrosymmetric R
2(8) ring motifs, giving two-dimensional layers lying parallel to (100). In (III), the water molecule of solvation lies on a crystallographic twofold rotation axis and bridges two carboxyl O atoms in an R
4(12) hydrogen-bonded motif, creating two R
3(10) rings, which together with a conjoined centrosymmetric R
2(8) ring incorporating both ammonium cations, generate two-dimensional layers lying parallel to (100). No π–π ring associations are present in any of the structures.
crystal structure; phenoxyacetic acid salts; MCPA; herbicides; ammonium carboxylates; hydrogen bonding
The structure of the title compound, C26H31NO12, contains an essentially planar quinoline skeleton, with the maximum deviation from the best plane being 0.055 (2) Å, and an oxane ring in a classical chair conformation with the following Cremer and Pople puckering parameters: Q = 0.586 (2) Å, θ = 11.5 (2)° and ϕ = 309.4 (10)°. One acetyl group displays rotational disorder with occupancies of 0.634 (8):0.366 (8). The crystal packing is stabilized by N—H⋯O hydrogen bonds, which link molecules into chains along the a axis. The packing is further stabilized by weak C—H⋯O interactions. The absolute configurations on the carbons in the oxane ring correspond to those of the commercial starting material and are unchanged in the well known mechanism of the Koenigs–Knorr synthesis.
The title compound [systematic name: (2R,3R,4S,5R,6R)-2-(acetoxymethyl)-6-propoxytetrahydro-2H-pyran-3,4,5-triyl triacetate], C17H26O10, was formed by a Koenigs–Knorr reaction of 2,3,4,6-tetra-O-acetyl-α-d-glucopyranosyl bromide and n-propanol. The central ring adopts a chair conformation. The crystal does not contain any significant interactions such as hydrogen bonds.
The title compound (delgradine), C41H43NO12, is a hetisine-type C20-diterpenoid alkaloid, isolated from the roots of Aconitum carmichaeli Debx. In the crystal structure, the molecule assumes an U-shaped conformation, the terminal benzene rings being approximately parallel and partially overlapped with each other. The molecule contains eight alicyclic and heterocyclic rings. Cyclohexane rings A and B adopt similar chair conformations; the six-membered rings C, D and E form a bicyclo[2.2.2]octane system with a boat conformation for each six-membered ring, the six-membered heterocyclic ring F has a screw-boat conformation and both of the five-membered rings G and H have envelope conformations. The crystal structure contains intermolecular O—H⋯O hydrogen bonding.
In the crystal structure of the title compound, C60H70N2O10·4CH3CN, the calixarene molecule adopts an open-cone conformation with two intramolecular O—H⋯O hydrogen bonds. The four benzene rings of the calixarene are twisted to the mean plane defined by four methylene C atoms bridging the benzene rings, with dihedral angles ranging from 57.74 (10) to 65.99 (12)°. Two pendant nitrophenyl rings are nearly perpendicular to each other, the dihedral angle being 70.9 (3)°. The asymmetric unit of the crystal structure contains four acetonitrile solvent molecules, one of which lies in the calix cavity and makes C—H⋯π interactions and another links with the calixarene via C—H⋯O hydrogen bonding. One tert-butyl group is disordered over two sets of sites, with a 0.736 (13):0.264 (13) occupancy ratio.
The title compound, C22H26O9, crystallizes with two independent molecules in the asymmetric unit in which the dihedral angles between the two benzene rings are 21.4 (2) and 5.1 (2)°. An intramolecular O—H⋯O hydrogen bond occurs in each molecule. Intermolecular C—H⋯O hydrogen bonds stabilize the crystal structure.
The enantiomerically pure title compound, C23H30O12, crystallizes in the chiral space group P212121. The O-acetylated-glucopyranoside moiety adopts a chair conformation. Numerous C—H⋯O interactions as well as a C—H⋯π interaction are present in the crystal structure.
In the title molecule, C28H28O9, the phenol and the benzene rings adjacent to the α,β-unsaturated ketone unit are inclined at 9.15 (13)° to each other. The terminal phenyl ring is oriented with respect to the phenol ring at a dihedral angle of 85.88 (13)°. In the crystal, the methylene C atoms of the dihydrodioxine ring are disordered over two sites with an occupancy ratio of 0.463 (18):0.537 (18), and both disordered components of the dihydrodioxine ring adopt twisted-chair conformations. An intramolecular O—H⋯O hydrogen bond and weak intermolecular C—H⋯O hydrogen bonds are present in the crystal structure.