Crystal Structure Of Methyl Research Articles

Methyl 2-acetamido-2-deoxy-β-D-glucopyranoside dihydrate and methyl 2-formamido-2-deoxy-β-D-glucopyranoside

Methyl 2-acetamido-2-deoxy-β-D-glucopyranoside (β-GlcNAcOCH(3)), (I), crystallizes from water as a dihydrate, C(9)H(17)NO(6)·H(2)O, containing two independent molecules [denoted (IA) and (IB)] in the asymmetric unit, whereas the crystal structure of methyl 2-formamido-2-deoxy-β-D-glucopyranoside (β-GlcNFmOCH(3)), (II), C(8)H(15)NO(6), also obtained from water, is devoid of solvent water molecules. The two molecules of (I) assume distorted (4)C(1) chair conformations. Values of φ for (IA) and (IB) indicate ring distortions towards B(C2,C5) and (C3,O5)B, respectively. By comparison, (II) shows considerably more ring distortion than molecules (IA) and (IB), despite the less bulky N-acyl side chain. Distortion towards B(C2,C5) was observed for (II), similar to the findings for (IA). The amide bond conformation in each of (IA), (IB) and (II) is trans, and the conformation about the C-N bond is anti (C-H is approximately anti to N-H), although the conformation about the latter bond within this group varies by ~16°. The conformation of the exocyclic hydroxymethyl group was found to be gt in each of (IA), (IB) and (II). Comparison of the X-ray structures of (I) and (II) with those of other GlcNAc mono- and disaccharides shows that GlcNAc aldohexopyranosyl rings can be distorted over a wide range of geometries in the solid state.

ChemInform Abstract: Rhodium-Catalyzed Reaction of Methyl Diazoacetoacetate with 5-(p- Methoxyphenyl)-1,3,4-oxathiazol-2-one: Isolation and Crystal Structure of Methyl 2-(p-Methoxyphenyl)-6-methyl-1,4,3-oxathiazine-5-carboxylate

ChemInform Abstract: Rhodium-Catalyzed Reaction of Methyl Diazoacetoacetate with 5-(p- Methoxyphenyl)-1,3,4-oxathiazol-2-one: Isolation and Crystal Structure of Methyl 2-(p-Methoxyphenyl)-6-methyl-1,4,3-oxathiazine-5-carboxylate

Crystal structure of methyl 3,4-di-O-benzyl-2-deoxy-2-C-nitromethyl-α-D-arabinopyranoside, C21H25NO6

C21H25NO6, monoclinic, P1211 (no. 4), a = 9.475(1) A, b = 7.1064(5) A, c = 15.048(2) A, = 101.234(9)°, V = 993.8 A, Z = 2, Rgt(F) = 0.032, wRref(F) = 0.083, T = 210 K. Source of material The title compound was synthesized by radical addition of nitromethane to di-O-benzyl-D-arabinal in the presence of cerium(IV) ammonium nitrate (CAN) [1]. The deprotonation of the CH-acidic precursor with potassium hydroxide prior to oxidation was important, which facilitated the radical generation remarkably. After isolation of the pure arabino isomer by column chromatography (cyclohexane/ethyl acetate 6:1), the product (50 mg) was mixed with ethyl acetate (2 ml) and hexane (1 ml), and toluene (2 ml) was added slowly at room temperature until a clear solution resulted. Colorless single crystals were obtained after slowly volatilizing the solvents at room temperature for four days. Experimental details All of the hydrogen atoms were located from the difference fourier map. One of the oxygen atoms (O6) is disordered over two sides. Using a free variable the SOFs were refined to give a ratio of 0.6 : 0.4.

Crystal structure of methyl 3,4,6-tri-O-benzyl-2-deoxy-2-C-nitromethyl-β-D-galactopyranoside, C29H33NO7

Crystal structure of methyl 3,4,6-tri-O-benzyl-2-deoxy-2-C-nitromethyl-β-D-galactopyranoside, C29H33NO7

Crystal Structure of Methyl 7-Hydroxy-5,6-bis(phenyl)-1,2,4-trimethylbicyclo-[2.2.1]hept-5-ene-2(endo)carboxylate

The title compound (C24H26O3) crystallized in the space group P21/c with the unit-cell parameters a = 11.114(2)A, b = 13.196(2)A, c = 27.609(2)A, β = 96.42(2)°. The structure was refined to an R-factor of 0.0514. X-ray crystallographic studies of the title compound (a norbornenol) confirm anti-orientation of the C(7)-OH group with respect to the C(5)-C(6) double bond. The two independent molecules in the asymmetric unit adopt identical conformations.

Mo‐Catalyzed Cross‐Metathesis Reaction of Propynylferrocene (Eur. J. Inorg. Chem. 25/2008)

AbstractThe cover picture shows the reaction scheme for the cross‐metathesis of (prop‐1‐yn‐1‐yl)ferrocene with substituted propynes effected by catalysts generated from [Mo(CO)6] and halophenols, situated on a background full of typical ferrocene, autumn‐like colors. The metathesis reaction affords good yields of unsymmetric ferrocenyl alkynes, thus offering a new alternative approach toward their preparation. Also shown are the crystal structure of methyl 4‐[(ferrocenyl)ethynyl]benzoate and the orbital diagram of its solid‐state π···π stacked dimer as calculated by DFT methods. A survey of various substrates and catalysts, results of X‐ray structure analysis and DFT calculations as well as electrochemical data for a series of (phenylethynyl)ferrocenes substituted at the phenyl ring are discussed in the article by M. Kotora, P. Štěpnička et al. on p. 3911 ff.

Crystal Structure of Methyl 2-(Benzyloxy)benzoate

The title compound, C15H14O3, crystallizes in the monoclinic space group P21/c with unit-cell parameters a = 12.8201(9), b = 12.3985(11), c = 7.6257(6)A, β = 90.930(9)°, Z = 4. The dihedral angle between the mean planes of the methyl-2benzoate ring and the benzyloxy ring is 8.0(2)°. Intermolecular hydrogen-bonding C-H…O interactions and π-π stacking interactions between nearby benzoate rings influence the twist angle between these two groups, and help to stabilize the crystal packing in the unit cell.

Crystal structure of methyl 3-amino-2,3-dideoxy-β- d- arabino-hexopyranoside. Stabilization of the crystal lattice by a double network of N–H⋯O, O–H⋯N and O–H⋯O interactions

The structure, conformation and configuration of methyl 3-amino-2,3-dideoxy-β- d- arabino-hexopyranoside were investigated by 1H NMR, 13C NMR and IR spectroscopy, as well as by optical rotation. The crystal structure was confirmed by single-crystal X-ray crystallographic analysis at 293 K and R = 0.0434 based on 910 independent reflections. The crystal belongs to the monoclinic system, space group of P2 1 with cell dimensions a = 6.050(1) Å, b = 7.284(1) Å, c = 10.289(2) Å, β = 104.69(3)°, D c = 1.341 Mg cm −3 and V = 438.9(1) Å 3 for Z = 2. Furthermore, the molecule has a typical 4 C 1 chair conformation. Hydrogen bonds between sugar molecules are responsible for stabilizing the crystal lattice.

Crystal Structure of Methyl 4-Hydroxy-3-nitro-2-(4-nitrophenyl)-5-(1,1,1-triphenyl-.LAMBDA.5-phosphanylidene)-1,3-cyclopentadiene-1-carboxylate

The crystal structure of methyl 4-hydroxy-3-nitro-2-(4-nitrophenyl)-5-(1,1,1-triphenyl-λ5-phosphanylidene)-1,3-cyclopentadiene-1-carboxylate was determined by crystallographic methods. The crystal, C31H23N2O7P, belongs to space group P21/n with cell dimensions of a = 11.0660(6), b = 21.1793(12), c = 11.7339(6)A, β = 100.1860(10)°, V = 2706.7(3)A3, Z = 4, Dcal = 1.390 Mg/m3, T = 120(2)K. The crystal structure was solved by direct methods and refined by full-matrix least squares to final values of R1 = 0.0559 and wR2 = 0.1122 with 4470 reflections (I > 2σ(I)). There is an intramolecular-hydrogen bond between the O(2) atom of the nitro group and the hydrogen of the OH group.

Synthesis of Six New 2‐Aryl‐N‐biphenyl Benzimidazoles and Crystal Structure of Methyl 4′‐[(2‐p‐Chlorophenyl‐1H‐benzimidazole‐1‐yl)‐methyl] biphenyl‐2‐carboxylate.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Synthesis of six new 2‐Aryl‐N‐biphenyl benzimidazoles and crystal structure of methyl 4′ [(2‐p‐Chlorophenyl‐1H‐benzimidazole‐1‐yl)‐methyl]biphenyl‐2‐carboxylate

AbstractSix new 2‐aryl‐N‐biphenyl benzimidazoles were designed and synthesized, starting with O‐phenylenediamine and carboxylic acids via cyclization, followed by N‐alkylation. All new compounds were identified by H NMR, IR, MS spectra and elemental analysis. The crystal structure of methyl 4′‐[(2‐p‐chlorophenyl‐1H benzimidazole‐1‐yl)methyl]biphenyl‐2‐carboxylate (4f) was determined by single crystal X‐raydiffraction.

Methyl 2-amino-4,5,6,7-tetrahydro-1-benzothiophene-3-carboxylate

The crystal structure of methyl 2-amino-4,5,6,7-tetrahydro-1-benzo- thiophene-3-carboxylate was studied. It is was observed that the structure of the given compound is composed of a thiophene ring substituted by a 2-amino group and a 3-methyl ester group. The carbonyl group has a cis orientation with respect to the C2=C3 double bond. It is shown that the crystal structure is stabilized by intra- and intermolecular N-H···O hydrogen bonds.

Crystal Structure and Solid‐State 13C NMR of Methyl α‐d‐Mannofuranoside †

The crystal structure of methyl α‐d‐mannofuranoside was determined by X‐ray crystallography. The C‐1–C‐2, C‐2–C‐3, C‐3–C‐4, C‐4–O and O‐4–C‐1 distances within the furanoside ring are 1.513(2), 1.523(2), 1.516(2), 1.445(2) and 1.422(2) Å, respectively. The hydrogen bonding consists of O–H–O interactions which include the anomeric oxygen but exclude the ring oxygen atom. The two hydroxyls OH‐6 and OH‐2 are H‐bond acceptors and donors with H···O distances of 1.92–1.93 Å, whereas the OH‐3 and OH‐5 are only H‐bond donor [H···O distance of 2.04(2) Å]. Additionally, OH‐6 participates in a weak hydrogen bond to the anomeric oxygen [H···O distance of 2.19(3) Å]. The crystalline methyl α‐d‐mannofuranoside adopts an 3 E ring conformation. The analysis of 13C CPMAS NMR chemical shifts for solid methyl α‐d‐mannofuranoside confirm such H‐bonding pattern. †This paper is dedicated to Professor Gérard Descotes on the occasion of his 70th birthday.

Crystal structure of methyl endo-8-cyano-exo-8-methyl-3-oxo-2-oxabicyclo[2.2.2]oct-5-ene-6-carboxylate.

A photochemical cycloaddition reaction of methyl 2-pyrone-5-carboxylate with methacrylonitrile mainly gave a [4 + 2] cycloadduct, assigned as methyl endo-8-cyano-exo-8-methyl-3-oxo-2-oxabicyclo[2.2.2]oct-5-ene-6-carboxylate, whose structure was determined by an X-ray diffraction study. The formation of the cycloadduct was reasonably explained by considering a biradical intermediate having a less steric hindrance between the methoxycarbonyl group and the cyano group.

A Novel Approach to the Syntheses of Functionalized, Water-Soluble Icosahedral Carboranyl Anions. Crystal Structure of Methyl N-[(Trimethylamineboryl)carbonyl]-L-tyrosinate: A Synthon for Novel Carboranylpeptides

New functionalized water-soluble carboranyl anions have been prepared from ortho-carborane through lithiation and subsequent derivatization. The reaction of Li2[1,2-C2B10H10] with Me3NBH2X produced the carboranylborane dianions, [1,2-(BH2X)-1,2-C2B10H10]2- (X = H (2a), CN (2b), COOMe (2c), COOH (2d)), while the reaction of [1-R-2-Li-C2B10H10]- with Me3NBH2X produced the monoanions [1-R-2-BH2X-C2B10H10]- (R = C6H5, X = H (2e), CN (2f), COOH (2h), COOCH3 (2g), CONHCH(CH2OH)COOMe (2i), CONHCH(CHMe2)COOMe (2j), CONHCH(4-CH2C6H4OH)- COOMe (2k); R = Me, X = H (2l), COOH (2m)). These water-soluble carboranylboranes have the potential of being effective hydrophilic boron neutron capture therapy (BNCT) agents. The crystal structure of the peptide precursor Me3NBH2CONHCH(4-CH2C6H4OH)COOMe (3b) which showed a special promise as a BNCT agent is also described.

ChemInform Abstract: Heterocycles with a Bridged Nitrogen Atom. Part 13. An Anomalous Example of the Sulfonating Action of Dimethyl Sulfate During an Attempt at the Methylation of 5‐Aminoindolizine. Crystal Structure of Methyl 5‐Morpholyl‐2‐(p‐nitrophenyl)indolizine‐1‐sulfonate.

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Methyl 4-O-beta-L-fucopyranosyl alpha-D-glucopyranoside hemihydrate. lerik@struc.su.se.

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: φH = −6.1° and ψH = 34.3°. The global energy minimum conformation as calculated by molecular mechanics in vacuo has φH = −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.

Methyl 4-O-β-L-fucopyranosyl α-D-glucopyranoside hemihydrate

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: φH = −6.1° and ψH = 34.3°. The global energy minimum conformation as calculated by molecular mechanics in vacuo has φH = −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.

Heterocycles with a Bridged Nitrogen Atom. 13. An Anomalous Example of the Sulfonating Action of Dimethyl Sulfate During an Attempt at the Methylation of 5-Aminoindolizine. Crystal Structure of Methyl 5-Morpholyl-2-(p-nitrophenyl)indolizine-1-sulfonate

The reaction of 5-morpholino-2-(p-nitrophenyl)indolizine with dimethyl sulfate gives the sulfonation product - methyl 5-morpholyl-2-(p-nitrophenyl)indolizine-1-sulfonate. Its structure was proved by X-ray crystallographic analysis.

Crystal Structure of Methyl 2-[1-(2,4-Dinitrophenyl)-3-methylpyrazol-5-yl] Acetate

Crystal Structure of Methyl 2-[1-(2,4-Dinitrophenyl)-3-methylpyrazol-5-yl] Acetate