PMCC PMCC

Search tips
Search criteria

Advanced
Results 1-25 (355058)

Clipboard (0)
None

Related Articles

1.  2,2,5,7,8-Penta­methyl­chroman-6-yl 2,3,4,6-tetra-O-acetyl-α-d-glucopyran­oside from synchrotron data 
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).
doi:10.1107/S160053681100626X
PMCID: PMC3052099  PMID: 21522460
2.  Methyl 3-O-α-l-fucopyranosyl β-d-glucopyran­oside tetra­hydrate 
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).
doi:10.1107/S1600536812041992
PMCID: PMC3515273  PMID: 23284493
3.  Phenyl 2-amino-N,6-O-dibenzyl-2,3-N,O-carbonyl-2-de­oxy-1-thio-β-d-glucopyran­oside 
In the crystal structure of the title compound, C27H27NO5S, the pyran­ose ring adopts a 4 C 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.
doi:10.1107/S1600536808027189
PMCID: PMC2959351  PMID: 21201084
4.  3,4-Dicyano­phenyl 2,3,4,6-tetra-O-acetyl-α-d-glucopyran­oside 
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.
doi:10.1107/S1600536807049860
PMCID: PMC2915021  PMID: 21200940
5.  2,3,4,6-Tetra-O-acetyl-2-phthalimido-β-d-glucopyran­oside 
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 [010]. The d configuration has been attributed on the basis of the synthesis and the β anomer has been determined from the structure.
doi:10.1107/S1600536810048099
PMCID: PMC3011788  PMID: 21589578
6.  Ethyl 4,6-O-benzyl­idene-2-de­oxy-N-phthalimido-1-thio-β-d-glucopyran­oside 
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.
doi:10.1107/S1600536810047070
PMCID: PMC3011798  PMID: 21589535
7.  4-(Dimeth­oxy­meth­yl)phenyl 2,3,4,6-tetra-O-acetyl-β-d-glucopyran­oside 
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.
doi:10.1107/S160053681201121X
PMCID: PMC3344139  PMID: 22606142
8.  2-Acetamido-2-de­oxy-3-O-β-d-galactopyranosyl-d-glucose dihydrate 
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.
doi:10.1107/S1600536809024775
PMCID: PMC2977301  PMID: 21583488
9.  2,3,4,6-Tetra-O-acetyl-1-O-(4-methoxy­cinnamo­yl)-β-d-glucopyran­ose 
Mol­ecules of the title compound, C24H28O12, are linked by inter­molecular C—H⋯O hydrogen bonds. Bond lengths and angles are normal.
doi:10.1107/S1600536808004698
PMCID: PMC2960856  PMID: 21201950
10.  Methyl 3-O-α-d-mannopyranosyl β-d-glucopyran­oside tetra­hydrate 
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.
doi:10.1107/S1600536808021454
PMCID: PMC2962246  PMID: 21203328
11.  Ethyl 3,6-di-O-benzyl-2-de­oxy-N-phthalimido-1-thio-β-d-glucopyran­oside 
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 [100] 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.
doi:10.1107/S1600536810047069
PMCID: PMC3011472  PMID: 21589536
12.  (4-Eth­oxy­benzo­yl)[8-(4-eth­oxy­benzo­yl)-2,7-di­meth­oxy­naphthalen-1-yl]methanone 
The title mol­ecule, C30H28O6, possesses crystallographically imposed twofold symmetry, with two central C atoms in the naphthalene unit lying on the rotation axis along [001]. The 4-eth­oxy­benzoyl groups at the peri positions of the naphthalene ring system are disordered over two sets of sites with occupancies of 0.769 (4) and 0.231 (4). They are directed in opposite directions from the naphthalene plane (anti orientation). For the major component, the dihedral angle between the aroyl benzene ring and the naphthalene ring system is 75.62 (13)° [minor component 75.5 (4)°], and that between the aroyl benzene rings is 32.58 (15)°. In the crystal, mol­ecules are linked via C—H⋯O and C—H⋯π inter­actions, forming a three-dimensional network.
doi:10.1107/S1600536813008581
PMCID: PMC3647849  PMID: 23723815
13.  1-De­oxy-l-mannitol (6-de­oxy-l-mannitol or l-rhamnitol) 
The crystalline form of 1-de­oxy-l-mannitol, C6H14O5, exists as an extensively hydrogen-bonded structure with each mol­ecule acting as a donor and acceptor for five hydrogen bonds. There are no unusual crystal-packing features; the absolute configuration was determined from the use of 6-de­oxy-l-mannose (l-rhamnose) as the starting material.
doi:10.1107/S1600536808024586
PMCID: PMC2960544  PMID: 21201694
14.  1,1,1,5,5,5-Hexafluoro-2,4-dimeth­oxy­pentane-2,4-diol 
The title compound, C7H10F6O4, was isolated as an unexpected product from a reaction of tantalum(V) methoxide with hexa­fluoro­acetyl­acetone in a methanol solution. The asymmetric unit consists of one half-mol­ecule with the middle C atom lying on a twofold axis. The crystal structure is stabilized by O—H⋯O and an array of C—H⋯F hydrogen-bonding inter­actions. These inter­actions link the mol­ecules into a stable supra­molecular three-dimensional network. The mol­ecules pack in a ribbon-like form in the ac plane as a result of these inter­actions.
doi:10.1107/S1600536811044813
PMCID: PMC3238828  PMID: 22199681
15.  1-De­oxy-1-fluoro-l-galactitol 
The crystal structure unequivocally confirms the relative stereochemistry of the title compound, C6H13FO5 [6-de­oxy-6-fluoro-d-galactitol or (2S,3R,4R,5S)-6-fluoro­hexane-1,2,3,4,5-penta­ol]. The absolute stereochemistry was determined from the use of d-galactose as the starting material. In the crystal, the molecules are linked by O—H⋯O and O—H⋯F hydrogen bonds, forming a three-dimensional network with each mol­ecule acting as a donor and acceptor for five hydrogen bonds.
doi:10.1107/S1600536810016624
PMCID: PMC2979521  PMID: 21579420
16.  4-(3-Fluoro-4-meth­oxy­phen­yl)-1-(4-meth­oxy­phen­yl)-5-(3,4,5-trimeth­oxy­phen­yl)-1H-imidazole 
In the title mol­ecule, C26H25FN2O5, the fluoro­meth­oxy-, meth­oxy- and trimeth­oxy-substituted benzene rings form dihedral angles of 12.65 (2), 84.15 (2) and 55.67 (2)°, respectively, with the imidazole ring. The crystal structure is stabilized weak inter­molecular C—H⋯F and C—H⋯O hydrogen bonds.
doi:10.1107/S160053681004465X
PMCID: PMC3011382  PMID: 21589391
17.  Ethyl 4,4′′-difluoro-5′-meth­oxy-1,1′:3′,1′′-terphenyl-4′-carboxyl­ate 
In the title compound, C22H18F2O3, the two fluoro-substituted rings form dihedral angles of 25.89 (15) and 55.00 (12)° with the central benzene ring. The eth­oxy group in the mol­ecule is disordered over two positions with a site-occupancy ratio of 0.662 (7):0.338 (7). In the crystal, mol­ecules are linked by C—H⋯O hydrogen bonds into chains along the a axis. The crystal packing is further stabilized by C—H⋯π and π—π inter­actions, with centroid–centroid distances of 3.8605 (15) Å.
doi:10.1107/S160053681105344X
PMCID: PMC3254511  PMID: 22259456
18.  2,2′-Bis(meth­oxy­meth­oxy)-3,3′-diphenyl-1,1′-binaphthalene 
The asymmetric unit of the title compound, C36H30O4, contains two crystallographically independent mol­ecules of similar geometry. In both mol­ecules, the meth­oxy­meth­oxy groups are disordered over two positions with refined site occupancies of 0.613 (3):0.387 (3) and 0.589 (4):0.411 (4). The dihedral angles between the naphthalene planes within the same mol­ecule are 71.72 (7) and 71.73 (8)°. In the crystal, neighbouring mol­ecules are linked by inter­molecular C—H⋯O hydrogen bonds, forming double chains parallel to the c axis.
doi:10.1107/S1600536810053018
PMCID: PMC3050160  PMID: 21522721
19.  (E)-1-[2-Hy­droxy-4,6-bis­(meth­oxy­meth­oxy)phen­yl]-3-[3-meth­oxy-4-(meth­oxy­meth­oxy)phen­yl]prop-2-en-1-one 
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.
doi:10.1107/S1600536811041213
PMCID: PMC3247344  PMID: 22219962
20.  4-Formyl­phenyl 2,3,4,6-tetra-O-acetyl-β-d-glucopyran­oside 
The pyran­oside ring in the title compound, C21H24O11, has a chair conformation with the substituted benzene ring occupying an equatorial position. The crystal packing is dominated by C—H⋯O inter­actions that lead to the formation of supra­molecular layers in the ab plane.
doi:10.1107/S1600536811008099
PMCID: PMC3099765  PMID: 21754109
21.  Ethyl ({5-[5′-(2-eth­oxy-2-oxoeth­oxy)-4,4′′-difluoro-1,1′:3′,1′′-terphenyl-4′-yl]-1,3,4-oxadiazol-2-yl}sulfan­yl)acetate 
In the title compound, C28H24F2N2O6S, the whole mol­ecule is disordered over two sites with refined occupancies of 0.778 (3) and 0.222 (3). The central benzene ring makes dihedral angles of 56.0 (4), 34.5 (4) and 70.9 (4)°, respectively, with the two terminal benzene rings and the 1,3,4-oxadiazole ring in the major component of the disordered mol­ecule. The corresponding angles in the minor component are 59.7 (16), 25.6 (13) and 75.5 (14)°. In the crystal, mol­ecules are linked via C—H⋯F, C—H⋯N, C—H⋯O and C—H⋯S hydrogen bonds into a three-dimensional network. In addition, C—H⋯π inter­actions are observed.
doi:10.1107/S1600536812005028
PMCID: PMC3295461  PMID: 22412572
22.  (2E)-3-{4-[(1H-1,3-Benzimidazol-2-yl)meth­oxy]-3-eth­oxy­phen­yl}-1-(4-bromo­phen­yl)prop-2-en-1-one monohydrate 
In the title compound, C25H21BrN2O3·H2O, the benzimidazole fragment and the water mol­ecule of crystallization are each disordered over two sets of sites of equal occupancy. The dihedral angles between the least-squares planes of the benzimidazole and the 3-eth­oxy- and 4-bromo­benzene rings are 86.9 (6) and 85.1 (1)°, respectively in one disorder component. The crystal packing is stabilized by inter­molecular O—H⋯O, O—H⋯N and N—H⋯N hydrogen bonds, which link the mol­ecules into chains along the a axis.
doi:10.1107/S1600536811008154
PMCID: PMC3099940  PMID: 21754118
23.  Penta­fluoro­phenyl (3R,4R,5S)-5-{[(3R,4R,5S)-5-azido­methyl-3,4-dimeth­oxy-2,3,4,5-tetra­hydro­furan-3-carboxamido]­meth­yl}-3,4-dimeth­oxy-2,3,4,5-tetra­hydro­furan-3-carboxyl­ate 
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)].
doi:10.1107/S1600536810038559
PMCID: PMC3009349  PMID: 21588915
24.  4-De­oxy-4-fluoro-β-d-gluco­pyranose 
4-De­oxy-4-fluoro-β-d-glucopyran­ose, C6H11FO5, (I), crystallizes from water at room temperature in a slightly distorted 4 C 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 TB 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.
doi:10.1107/S0108270110034001
PMCID: PMC3089016  PMID: 20921614
25.  6-Azido-6-de­oxy-α-l-galactose (6-azido-l-fucose) monohydrate 
Although 6-azido-6-de­oxy-l-galactose in aqueous solution is in equilibrium between the open-chain, furan­ose and pyran­ose forms, it crystallizes solely as 6-azido-6-de­oxy-α-l-galactopyran­ose monohydrate, C6H11N3O5·H2O, with the six-membered ring adopting a chair conformation. The structure exists as hydrogen-bonded chains, with each mol­ecule acting as a donor and acceptor of five hydrogen bonds. There are no unusual crystal packing features and the absolute configuration was determined from the use of 1-azido-1-de­oxy-d-galactitol as the starting material.
doi:10.1107/S1600536808022563
PMCID: PMC2962088  PMID: 21203271

Results 1-25 (355058)