Characterization of a γ-radiation-induced decomposition product of thymidine. Crystal and molecular structure of the (−)cis(5R,6S) thymidine glycol

1987 ◽  
Vol 65 (11) ◽  
pp. 2618-2623 ◽  
Author(s):  
Frank E. Hruska ◽  
Rudy Sebastian ◽  
André Grand ◽  
Lucienne Voituriez ◽  
Jean Cadet
Keyword(s):  
Pyrimidine Ring ◽  
Orthorhombic Space Group ◽  
Γ Radiation ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Cell Dimensions ◽  
Radiation Induced ◽  
Induced Decomposition

X-ray crystallography was used to determine the structure of (−)cis(5R,6S)-5,6-dihydroxy-5,6-dihydrothymidine, a γ-radiation induced product of thymidine. The crystals belong to the orthorhombic space group P212121 and have cell dimensions a = 8.420(1) Å, b = 10.422(1) Å, and 13.552(1) Å. The half-chair pucker of the 5,6-saturated pyrimidine ring is similar to that observed for the isolated base with the cis configuration, and is described by the Cremer–Pople parameters Q = 0.48 Å, θ = 62°, and [Formula: see text]. The conformation about the N-glycosyl bond is anti; the χ angle (−111.6(5)°) lies at one extreme of the range previously seen for nucleosides (−180 to −115°). The pucker 2T1 of the sugar (P = 151.2°; τm = 36.5°) contrasts with the O4′-endo type of pucker seen in 5,6-dihydrothymidine (0T4) and (5S)-5-hydroxy-5,6-dihydrothymidine (0T1). The conformation about the C4′—C5′ bond is gauche+. The solid state structure is similar to that determined in aqueous solution by 1H nmr.

The reaction of chloro(triphenylphosphine)gold(I) with 1-methylthymine

1987 ◽  
Vol 65 (7) ◽  
pp. 1568-1575 ◽  
Author(s):  
R. Faggiani ◽  
H. E. Howard-Lock ◽  
C. J. L. Lock ◽  
M. A. Turner
Keyword(s):  
Aqueous Methanol ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Cell Dimensions ◽  
Cell Data ◽  
Unit Cell Data ◽  
Related Compounds ◽  
C Nmr

1-Methylthyminato-N3-triphenylphosphinegold(I) was prepared by reacting chloro(triphenylphosphine)gold(I) with 1-methylthymine in aqueous methanol at pH 11. The product was examined by X-ray crystallography and was found to have the orthorhombic space group C2221 (no. 20) with cell dimensions a = 12.760(7) Å, b = 11.530(2) Å, c = 31.893(5) Å, and eight formula units in the unit cell. Data were collected with use of MoKα radiation and a Syntex P21, diffractometer. The crystal structure was determined by standard methods and refined to R = 0.112 and Rw = 0.076 on the basis of 4760 unique reflections. Bond lengths and bond angles are normal. Packing in the crystal lattice is dominated by the triphenylphosphine rings which arrange roughly as blades of a propellor and are the source of the crystal's chirality. The title and related compounds were also examined by 1H nmr, 13C nmr, and vibrational spectroscopy.

Configurational and conformational studies on condensation products of biogenic amines with 2,5-anhydro-D-mannose

1985 ◽  
Vol 63 (11) ◽  
pp. 2915-2921 ◽  
Author(s):  
Ian M. Piper ◽  
David B. MacLean ◽  
Romolo Faggiani ◽  
Colin J. L. Lock ◽  
Walter A. Szarek
Keyword(s):  
Hydrogen Bond ◽  
Intermolecular Hydrogen Bond ◽  
Direct Methods ◽  
Conformational Studies ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Twist Conformation ◽  
Cell Dimensions ◽  
Internal Hydrogen Bond

The products of a Pictet–Spengler condensation of tryptamine and of histamine with 2,5-anhydro-D-mannose have been studied by X-ray crystallography to establish their absolute configuration. 1(S)-(α-D-Arabinofuranosyl)-1,2,3,4-tetrahydro-β-carboline (1), C16H20N20O4, is monoclinic, P21 (No. 4), with cell dimensions a = 13.091(4), b = 5.365(1), c = 11.323(3) Å, β = 115.78(2)°, and Z = 2. 4-(α-D-Arabinofuranosyl)imidazo[4,5-c]-4,5,6,7-tetrahydropyridine (3), C11H17N3O4, is orthorhombic, P212121 (No. 19), with cell dimensions a = 8.118(2), b = 13.715(4), c = 10.963(3) Å, and Z = 4. The structures were determined by direct methods and refined to R1 = 0.0514, R2 = 0.0642 for 3210 reflections in the case of 1, and to R1 = 0.0312, R2 = 0.0335 for 1569 reflections in the case of 3. Bond lengths and angles within both molecules are normal and agree well with those observed in related structures. In 3 the base and sugar adopt a syn arrangement, which is maintained by an internal hydrogen bond between O(2′) and N(3). The sugar adopts a normal 2T3 twist conformation. The sugar has the opposite anti arrangement in the β-carboline 1 and the conformation of the sugar is unusual; it is close to an envelope conformation with O(4′) being the atom out of the plane. This conformation is caused by a strong intermolecular hydrogen bond from O(5′) in a symmetry-related molecule to O(4′). Both compounds are held together in the crystal by extensive hydrogen-bonding networks. The conformations of the compounds in solution have been investigated by 1H nmr spectroscopy, and the results obtained were compared with those obtained by X-ray crystallography for 1 and 3.

Structural and vibrational studies of 1,1,3,3-tetracyanopropane and 2,2,4,4,6-pentacyanocyclohexenamine

1987 ◽  
Vol 65 (2) ◽  
pp. 261-270 ◽  
Author(s):  
R. A. Bell ◽  
B. E. Brown ◽  
M. Duarte ◽  
H. E. Howard-Lock ◽  
C. J. L. Lock
Keyword(s):  
Unit Cell ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
X Ray Crystallography ◽  
New Methods ◽  
Cell Dimensions ◽  
Cell Data ◽  
Unit Cell Data ◽  
Monoclinic Cell ◽  
C Nmr

1,1,3,3-Tetracyanopropane, 1, was prepared in low yields by a literature method with 2,2,4,4,6-pentacyanocyclohexenamine, 2, as a major by-product. The products were examined by X-ray crystallography. 1 has an orthorhombic space group, Pbcn (No. 60) with cell dimensions, a = 7.158(2), b = 10.510(3), c = 9.733(2) Å and has four formula units in the unit cell. 2 has a monoclinic cell, P21/c (No. 14) with cell dimensions a = 14.368(3), b = 6.626(1), c = 12.300(2) Å, β = 115.60(1)° and has 4 formula units in the unit cell. Data were collected with use of MoKα radiation and a Nicolet P3 diffractometer. The crystal structures were determined by standard methods and refined to Rw = 0.037 (1) and Rw = 0.040 (2) on the basis of 782 and 2108 unique reflections. Bond lengths and angles in the two compounds are normal. 2 has what has been considered to be the less likely tautomeric structure. Both compounds were examined by 1H, 13C nmr, vibrational spectroscopy, and mass spectroscopy. For 2 there was no evidence of the alternative tautomeric structure. New methods were developed for the preparation of both compounds and the mechanism of the original reaction rationalized.

scholarly journals Synthesis and characterization of a new bis-NHC palladium complex and its catalytic activity in the Mizoroki–Heck reaction

2020 ◽  
Vol 44 (11-12) ◽  
pp. 684-688
Author(s):  
Can Feng ◽  
Cheng-xin Liu ◽  
Yu-fang Wang ◽  
Jin Cui ◽  
Ming-jie Zhang
Keyword(s):  
Palladium Complex ◽  
Coupling Reaction ◽  
Aryl Halides ◽  
Heck Coupling ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Excellent Stability ◽  
C Nmr

A new bis- N-heterocyclic carbene palladium complex, (C13H9N2F2)2PdCl2, is synthesized by a three-step reaction and characterized by 1H NMR and 13C NMR spectroscopy as well as by X-ray crystallography. This new bis- N-heterocyclic carbene palladium complex has excellent stability and is capable of efficiently catalyzing the Mizoroki–Heck coupling reaction of aryl halides with acrylates.

scholarly journals Synthesis And Structural Characterization Of 1-Butyl-2,3-Dimethylimidazolium Bromide And Iodide

2007 ◽  
Vol 62 (6) ◽  
pp. 868-870 ◽  
Author(s):  
Johanna Kutuniva ◽  
Raija Oilunkaniemi ◽  
Risto S. Laitinen ◽  
Janne Asikkala ◽  
Johanna Kärkkäinen ◽  
...  
Keyword(s):  
Unit Cell ◽  
Monoclinic Crystal System ◽  
Monoclinic Crystal ◽  
Space Group ◽  
X Ray ◽  
Crystal System ◽  
H Nmr ◽  
Cell Dimensions ◽  
Unit Cell Dimensions

1-Butyl-2,3-dimethylimidazolium bromide {(bdmim)Br} (1) and iodide {(bdmim)I} (2) were prepared conveniently by the reaction of 1,2-dimethylimidazole and the corresponding 1-halobutane. The compounds were characterized by 1H and 13C{1H} NMR spectroscopy as well as by X-ray single crystal crystallography. 1 crystallizes in the monoclinic crystal system, space group P21/n, with Z = 4, and unit cell dimensions a = 8.588(2), b = 11.789(1), c = 10.737(2) Å, β = 91.62(3)°. Compound 2 crystallizes in the monoclinic crystal system, space group P21/c, with Z = 8, and unit cell dimensions a = 10.821(2), b = 14.221(3), c = 15.079(2) Å , β = 90.01(3)°. The lattices of the salts are built up of 1-butyl-2,3- dimethylimidazolium cations and halide anions. The cations of 1 form a double layer with the imidazolium rings stacked together due to π interactions. The Br− anions lie approximately in the plane of the imidazolium ring, and the closest interionic Br···H contacts span a range of 2.733(1) - 2.903(1) Å. Compound 2 shows no π stacking interactions. The closest interionic I···H contacts are 2.914(1) - 3.196(1) Å

Preparation, Crystal Structure and Spectroscopic Characterization of [Ga(OH)(SO4)(terpy)(H2O)] · H2O (terpy=2,2’:6’,2-Terpyridine): The First Characterized Gallium(III) Sulfato Complex

2004 ◽  
Vol 59 (3) ◽  
pp. 291-297 ◽  
Author(s):  
Andreas Sofetis ◽  
Giannis S. Papaefstathiou ◽  
Aris Terzis ◽  
Catherine P. Raptopoulou ◽  
Theodoros F. Zafiropoulos
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Nmr Spectroscopy ◽  
Good Yield ◽  
Spectroscopic Data ◽  
Spectroscopic Characterization ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr

The reaction of Ga2(SO4)3·18H2O and excess 2,2′:6′,2″-terpyridine (terpy) in MeOH / H2O leads to [Ga(OH)(SO4)(terpy)(H2O)]·H2O (1·H2O] in good yield. The structure of the complex has been determined by single-crystal X-ray crystallography. The GaIII atom in 1·H2O is 6-coordinate and ligation is provided by one terdentate terpy molecule, one monodentate sulfate, one terminal hydroxide and one terminal H2O molecule; the coodination polyhedron about the metal is described as a distorted octahedron. There is an extensive hydrogen-bonding network in the crystal structure which generates corrugated layers parallel to bc. The new complex was characterized by IR and 1H NMR spectroscopy. The spectroscopic data are discussed in terms of the nature of bonding

Molecular conformation of 2′-deoxy-3′,5′-di-O-acetyl adenosine. Crystal structure and high resolution proton nuclear magnetic resonance investigations

1987 ◽  
Vol 65 (2) ◽  
pp. 326-331 ◽  
Author(s):  
Leo H. Koole ◽  
Henk M. Buck ◽  
Jan A. Kanters ◽  
Arie Schouten
Keyword(s):  
Crystal Structure ◽  
Molecular Conformation ◽  
Proton Nuclear Magnetic Resonance ◽  
Solution Conformation ◽  
Orthorhombic Space Group ◽  
One Dimensional ◽  
X Ray ◽  
H Nmr ◽  
Conformational Preferences ◽  
Cell Dimensions

2′-Deoxy-3′,5′-di-O-acetyl adenosine crystallizes in the orthorhombic space group P212121, and the cell dimensions are a = 7.768(1) Å, b = 12.890(1) Å, c = 15.495(1) Å; Z = 4 molecules per cell. Least-squares refinement converged at R = 0.054 for 1752 observed reflections. The adenine bases are linked via N6—H … N1 and N6—H … N7 hydrogen bonds, in such a way that infinite one-dimensional chains are formed. Comments are made on the fact that this structure is entirely different from the parallel dimer that was found for 3′,5′-di-O-acetyl thymidine. Furthermore, the conformational preferences of the title compound in aqueous solution have been determined with 300- and 500-MHz 1H nmr. It is found that the X-ray structure and the solution conformation are essentially similar, except for the C4′—C5′ conformation, that is γ− in the solid state, and predominantly γ+ in solution.

The preparation, X-ray crystal structure, and spectroscopic characterization of pentafluorophenyl-bis(pentafluorophenylthio)sulfonium hexafluoroarsenate, [(C6F5S)2SC6F5][AsF6]

1998 ◽  
Vol 76 (7) ◽  
pp. 1050-1059 ◽  
Author(s):  
Scott Brownridge ◽  
T Stanley Cameron ◽  
Jack Passmore ◽  
Gabriele Schatte ◽  
George W Sutherland
Keyword(s):  
Crystal Structure ◽  
Raman Spectroscopy ◽  
Room Temperature ◽  
Spectroscopic Characterization ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
Cell Dimensions ◽  
Ft Raman Spectroscopy ◽  
Ft Raman

Pentafluorophenyl-bis(pentafluorophenylthio)sulfonium hexafluoroarsenate, [(C6F5S)2SC6F5][AsF6], was prepared by the reaction of (C6F5)2S2 and AsF5 in liquid SO2 at room temperature. The compound has been characterized by single-crystal X-ray and powder diffraction, and IR and FT-Raman spectroscopy. Crystals of [(C6F5S)2SC6F5][AsF6] are orthorhombic, space group P212121 (cell dimensions measured at room temperature in brackets): a = 13.132(3) [13.157(2)] Å, b = 21.477(4) [21.575(3)] Å, c = 8.770(2) [8.775(1)] Å, α = ß = γ = 90.00°; V = 2473.3(9) Å3, Z = 4, temperature = 181 ± 1 K. The structure consists of [AsF6]- anions and [(C6F5S)2SC6F5]+ cations that have a different structure than the related [X2MMMX]+ cations (M = S, Se; X = Cl, Br), which contain a trichalcogen chain with a pronounced chalcogen-chalcogen bond alternation. Ab initio calculations suggest the observed [(C6F5S)2SC6F5]+ geometry is due to steric and solid state effects. Comparison of the Raman spectra of [(C6F5)S2SC6F5][AsF6], [Cl2SSSCl][AsF6], and [(CH3)2ClS3]+ implies that [(CH3)2ClS3]+ has a structure with equal sulfur-sulfur distances, and therefore the structure is likely [(CH3S)2SCl]+ and probably not the previously reported [(CH3)2SSSCl]+.Key words: [R3X3]+ cations, X-ray crystal structure, FT-Raman spectroscopy, [(C6F5S)2SC6F5]+, pentafluorophenyl-bis(pentafluorophenylthio)sulfonium cation, hexafluoroarsenate.

Conformation of methyl 3,6-dideoxy-α-D-arabino-hexopyranoside, the immunodominant sugar of Salmonella serogroup D1: crystal structure, 1H nmr analysis, and semi-empirical calculations

1985 ◽  
Vol 63 (3) ◽  
pp. 739-744 ◽  
Author(s):  
George I. Birnbaum ◽  
David R. Bundle
Keyword(s):  
Minimum Energy ◽  
Direct Methods ◽  
Anomeric Effect ◽  
Pyranose Ring ◽  
Hydrogen Atoms ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
H Nmr ◽  
Cell Dimensions ◽  
Semi Empirical

Methyl 3,6-dideoxy-α-D-arabino-hexopyranoside (methyl tyveloside) crystallizes in the orthorhombic space group P212121 and the cell dimensions are a = 7.478(1), b = 7.933(1), c = 14.064(1) Å. X-ray intensity data were measured with a diffractometer and the structure was solved by direct methods. Least-squares refinement, which included all hydrogen atoms, converged at R = 0.038. The pyranose ring exists as an almost perfect 4C1 chair and the conformation adopted by the glycosidic methyl group is in agreement with the requirements of the exo-anomeric effect. Both acetal oxygen atoms act as hydrogen-bond acceptors, and the [Formula: see text] bond distances are in agreement with this feature. The 1H nmr spectrum shows that the conformation of the pyranose ring in aqueous solution is indistinguishable from that in the crystal. The minimum energy conformation of a pentasaccharide fragment of a Salmonella O-antigen, calculated with tyvelose coordinates obtained by bond modification, is in good agreement with the conformation which was calculated with tyvelose coordinates obtained from the X-ray analysis.

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