Structure and conformation of 5-methoxymethyl-1-(2′-deoxy-β-D-lyxofuranosyl)uracil

1986 ◽  
Vol 64 (7) ◽  
pp. 1305-1309 ◽  
Author(s):  
J. Wilson Quail ◽  
Irena Ekiel ◽  
Ossama A. L. El-Kabbani ◽  
Guy Tourigny ◽  
Louis T. J. Delbaere ◽  
...  
Keyword(s):  
Crystallographic Analysis ◽  
Side Chain ◽  
Nmr Analysis ◽  
Space Group ◽  
X Ray ◽  
Envelope Conformation ◽  
Sugar Ring ◽  
Glycosidic Conformation

The structure of the nucleoside 5-methoxymethyl-1-(2′-deoxy-β-D-lyxofuranosyl)uracil (MMdLU) was deduced by X-ray crystallographic analysis. MMdLU crystallized in space group P21 with a = 8.719(4), b = 13.188(3), c = 5.701(3) Å, β = 109.56(2)° and Z = 2; R = 0.040 for 1208 unique reflections with net I > 2σ(I). The furanose ring adopts the rare C(4′)—exo envelope conformation (4E). The glycosyl linkage is anti (χ = 243.5°) and the C(5′) side chain has the t conformation. The conformation was also determined in solution by nmr analysis. The sugar ring exists in the N-conformation (97 ± 5%), the populations of the three rotamers about the exocyclic C(4′)—C(5′) bond were estimated to be g+:t:g− = 23%:59%:18% and the glycosidic conformation is predominantly anti.

Structure and conformation of 5-methoxymethyl-2′-deoxycytidine

1990 ◽  
Vol 68 (6) ◽  
pp. 836-841 ◽  
Author(s):  
Zongchao Jia ◽  
Guy Tourigny ◽  
Louis T. J. Delbaere ◽  
Allan L. Stuart ◽  
Sagar V. Gupta
Keyword(s):  
Three Dimensional ◽  
Antiviral Agent ◽  
Crystallographic Analysis ◽  
Dimensional Structure ◽  
Side Chain ◽  
X Ray ◽  
Envelope Conformation ◽  
Anti Conformation ◽  
Sugar Ring ◽  
Antiherpes Activity

The three-dimensional structure of the antiviral agent 5-methoxymethyl-2′-deoxycytidine (MMdCyd) was deduced by X-ray crystallographic analysis. MMdCyd crystallized in space group P21 with a = 7.9255(6) Å; b = 16.1505(15) Å, c = 10.1861(5) Å, β = 103.801(5)°, and Z = 4 (2 molecules per asymmetric unit); R = 0.044 (Rw = 0.046) for 2560 observed reflections with net I > 3σ(I). The furanose ring adopts the C(3′)-exo envelope conformation (3E) in molecule A and the C(2′)-endo envelope conformation (2E) in molecule B. In the sugar ring of both crystallographically independent molecules A and B, the side chain at C(5′) has the g+ conformation. This appears to be a preferred geometry required for antiherpes activity in 2′-deoxyribonucleosides. The glycosyl linkage is anti with χ = 213.7° for the A molecule and 222.2° for the B molecule. With respect to this anti conformation, the methoxy group at C(5) in molecules A and B exhibits different conformations; it is on the same side of the pyrimidine plane as the deoxyribofuranose ring oxygen (O4′) in molecule B and on the opposite side in molecule A. Keywords: antiherpes agent, conformation, 5-methoxymethyl-2′-deoxycytidine, crystal structure.

X-ray powder diffraction data for ertapenem side chain, C20H19N3O7S

2017 ◽  
Vol 32 (3) ◽  
pp. 203-205
Author(s):  
Xiang Lin ◽  
Wei Ling Zhuo ◽  
Qiao Hong Du ◽  
Xi Lin Peng ◽  
Hui Li
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Unit Cell Volume ◽  
Unit Cell ◽  
Side Chain ◽  
Powder Diffraction Data ◽  
Unit Cell Parameters ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters

X-ray powder diffraction data, unit-cell parameters, and space group for ertapenem side chain, C20H19N3O7S, are reported [a = 4.907(6) Å, b = 18.686(3) Å, c = 22.071(1) Å, α = γ = 90°, β = 90.759(5)°, unit-cell volume V = 2023.82 Å3, Z = 4, ρcal = 1.462 g cm−3, and space group P21/c]. All measured lines were indexed and are consistent with the P21/c space group. No detectable impurity was observed.

Crystallization and preliminary X-ray crystallographic analysis of the Pseudomonas aeruginosa cyclohexadienyl dehydratase

1999 ◽  
Vol 55 (2) ◽  
pp. 539-541
Author(s):  
Palangpon Kongsaeree ◽  
Jun Liang ◽  
Roy A. Jensen ◽  
Jon Clardy
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Crystal Form ◽  
High Energy ◽  
Crystallographic Analysis ◽  
Unit Cell ◽  
Space Group ◽  
X Ray ◽  
Cell Dimensions ◽  
Unit Cell Dimensions

The title protein has been crystallized in a new crystal form. The crystals belong to the cubic space group P4132 (or P4332) with unit-cell dimensions a = b = c = 126.1 Å at 100 K and typically diffract beyond 1.6 Å at the Cornell High Energy Synchotron Source (CHESS) A1 beamline.

The crystal and molecular structure of 5-(propyn-1-yl)-1-(β-D-arabinofuranosyl)uracil. A very short C≡C triple bond

1984 ◽  
Vol 62 (1) ◽  
pp. 147-152 ◽  
Author(s):  
Mlroslaw Cygler ◽  
Wayne F. Anderson ◽  
Jerzy Giziewicz ◽  
Morris J. Robins
Keyword(s):  
Triple Bond ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Pyrimidine Ring ◽  
Side Chain ◽  
X Ray Diffraction ◽  
X Ray ◽  
Anti Conformation ◽  
Sugar Ring ◽  
Glycosidic Torsion Angle

The crystal structure of 5-(propyn-1-yl)-1-(β-D-arabinofuranosyl)uracil, an analog of the active antiherpes nucleoside 1-(β-D-arabinofuranosyl)thymine, was determined by X-ray diffraction. The compound crystallizes in the space group P212121 with a = 4.925(1), b = 14.326(2), c = 17.454 Å. Reflections were measured on a diffractometer and the structure was solved by direct methods. Least-squares refinement converged at R = 0.032 for 1159 observed reflections. The sugar ring exhibits an 3E or a C(3′)endo conformation with a pseudorotation angle P = 28.3° and puckering amplitude τm = 31.7°. The orientation of the —CH2OH side chain is g+. The base is in an anti conformation with respect to the sugar ring, with a glycosidic torsion angle χ = 33.7°. Changes in the C(5)—C(6) and C(6)—N(1) bond lengths suggest some interaction of the propynyl group with the pyrimidine ring. The C≡C bond length of 1.121 Å is very short. Its shortening could result from intermolecular interactions with the neighboring pyrimidine ring and nearby oxygen atoms.

Intramolecular Condensation Reactions of S-Methylmethionine Coordinated to Cobalt(III)

1994 ◽  
Vol 47 (3) ◽  
pp. 501 ◽  
Author(s):  
PM Angus ◽  
BT Golding ◽  
SS Jurisson ◽  
AM Sargeson ◽  
AC Willis
Keyword(s):  
Crystallographic Analysis ◽  
Monoclinic Space Group ◽  
Sulfonium Salt ◽  
Space Group ◽  
X Ray ◽  
Condensation Reactions ◽  
Aqueous Base ◽  
Intramolecular Condensation ◽  
R Factors

The sulfonium salt [(en)2CoO2CCH(NH2)(CH2)2S(CH3)2]3+ (en = ethane-1,2-diamine), prepared by methylation of the thioether group of N,O-coordinated methionine , undergoes a set of complex, intramolecular condensations, oxidations, and rearrangements in aqueous base to give a novel pentadentate cobalt(III) complex (c. 20%) of the 1,9-diamino-4-hydroxy-3,7-diazanonane-4-carboxylate ion ( dhnc ). Its structure has been determined by X-ray crystallographic analysis as trans(O,O)-[Co( dhnc )(OH2)](ClO4)2.2H2O. The crystals were monoclinic, space group P 21/c with a 9.053(2), b 29.437(7), c 7.661(1) Ǻ, β 106.63(1)°, and Z 4; 2383 data with I ≥ 3σ(I) were refined to conventional R factors of 0.046 and 0.060. Investigations concerning the mechanism for the formation of this complex are described.

Revised Absolute Configurations of Latifolic Acid and the Pyrrolizidine Alkaloid Latifoline

1988 ◽  
Vol 41 (11) ◽  
pp. 1781 ◽  
Author(s):  
JN Roitman ◽  
RY Wong
Keyword(s):  
Carboxylic Acid ◽  
Single Crystal ◽  
Pyrrolizidine Alkaloid ◽  
Crystallographic Analysis ◽  
Side Chain ◽  
X Ray ◽  
The Absolute ◽  
Absolute Stereochemistry

The absolute stereochemistry of (+)- latifolk acid has been determined by single-crystal X-ray crystallographic analysis to be (2S,3R,4R)-3- hydroxy-2,4-dimethyl-5-oxotetrahydrofuran-3-carboxylic acid. The configuration of the three chiral centres is opposite to that presently recorded in the literature. Accordingly, the configuration of the pyrrolizidine alkaloid, latifoline, which includes a latifolic acid side chain, must be revised.

Structure and conformation of hydroxylubimin, a sesquiterpenoid phytoalexin

1977 ◽  
Vol 55 (10) ◽  
pp. 1619-1623 ◽  
Author(s):  
George I. Birnbaum
Keyword(s):  
Structure Analysis ◽  
Direct Methods ◽  
Membered Ring ◽  
Side Chain ◽  
Equatorial Position ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray ◽  
Independent Molecules ◽  
Chiral Centers

In order to determine the orientation of the isopropenyl group and confirm the stereochemistry at other chiral centers in lubimin (1) and hydroxylubimin (2), two antifungal sesquiterpenes, an X-ray structure analysis of 2 was carried out. Crystals of 2 are orthorhombic, space group P212121, a = 6.190, b = 7.210, c = 63.082 Å, Z = 8. The structure was solved by direct methods and refined to R = 0.045. In both independent molecules the six-membered ring is chair-shaped with all four substituents equatorially oriented. The five-membered ring, attached by a spiro junction, is a half-chair with the isopropenyl substituent in an equatorial position. This side-chain is trans to the methyl-bearing carbon in the six-membered ring.

Crystal structure of bisoprolol fumarate Form I, (C18H32NO4) (C4H2O4)0.5

2019 ◽  
Vol 35 (1) ◽  
pp. 34-40
Author(s):  
James A. Kaduk ◽  
Amy M. Gindhart ◽  
Thomas N. Blanton
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Density Functional ◽  
Side Chain ◽  
Powder Diffraction Data ◽  
Powder Diffraction File ◽  
Space Group ◽  
X Ray

The crystal structure of bisoprolol fumarate Form I has been solved and refined using synchrotron X-ray powder diffraction data and optimized using density functional techniques. Bisoprolol fumarate Form I crystallizes in space group P-1 (#2) with a = 8.165 70(5) Å, b = 8.516 39(12) Å, c = 16.751 79(18) Å, α = 89.142(1)°, β = 78.155(1)°, γ = 81.763(1)°, V = 1128.265(10) Å3, and Z = 2. The neutral side chain of the bisoprolol cation is probably disordered. The cation and anion are linked by N–H⋯O and O–H⋯O hydrogen bonds. The cations are also linked by N–H⋯O hydrogen bonds. The result is alternating layers of hydrophilic and hydrophobic layers parallel to the ab-plane. The density of the structure is relatively low at 1.130 g cm−3, but there are no obvious voids in the structure. The powder pattern is included in the Powder Diffraction File™ as entry 00-066-1625.

The reaction of tetrasulphur dinitride with norbornadiene; the crystal and molecular structure of S4N2•C7H8, an eight-membered C2S4N2 heterocycle

1983 ◽  
Vol 61 (6) ◽  
pp. 1185-1188 ◽  
Author(s):  
Hans Koenig ◽  
Richard T. Oakley ◽  
A. Wallace Cordes ◽  
Mark C. Noble
Keyword(s):  
Molecular Structure ◽  
Least Squares ◽  
Dihedral Angle ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Crystallographic Analysis ◽  
Monoclinic Space Group ◽  
Full Matrix ◽  
Space Group ◽  
X Ray

The reaction of tetrasulphur dinitride with norbornadiene produces the 1:1 adduct S4N2•C7H8; X-ray crystallographic analysis of this compound reveals that olefin addition cleaves one of the sulphur–sulphur bonds of S4N2, yielding a novel eight-membered C2S4N2 ring. Crystals of S4N2•C7H8 are monoclinic, space group P21/c, a = 6.127(1), b = 17.369(1), c = 9.580(1) Å, β = 106.74(1)°, V = 1003.8(5) Å3Z = 4. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.039. The S—S—N—S—N—S fragment of the C2S4N2 ring is planar to within 0.15 Å. The S—C—C—S unit is folded out of this plane to produce a dihedral angle of 74.5°.

Rearrangements in the Furan Series. V. Reaction of 2,4-Di-p-methylanilino-cyclopent-2-enone With Maleic Anhydride

1991 ◽  
Vol 44 (11) ◽  
pp. 1533 ◽  
Author(s):  
BR Darcy ◽  
KG Lewis ◽  
PJ Oliver ◽  
MF Mackay
Keyword(s):  
Acetic Acid ◽  
Maleic Anhydride ◽  
Spectroscopic Data ◽  
Crystallographic Analysis ◽  
Full Matrix ◽  
Space Group ◽  
X Ray ◽  
Furan Series

A yellow product formed in the reaction of 2,4-di-p-methylanilinocyclopent-2-enone with maleic anhydride has been shown by X-ray crystallographic analysis to be (4′-p-methylanilino-1′-p-methylphenyl-2′,5′-dioxo-1′,2′,3′,5′,6′,6′a- hexahydrocyclopenta[b]pyrrol-3′-yl)acetic acid (3) in accord with the spectroscopic data. Monoclinic crystals of (3) belong to the space group P21/n with a 13.399(2), b 8.386(1), c 17.935(3)Ǻ, β 92.06(2)° and Z 4. Full-matrix refinement with 2292 observed data converged at R 0.063.

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