TY - JOUR A1 - Rosenau, Th. A1 - Mereiter, K. A1 - Jäger, Christian A1 - Schmid, P. A1 - Kosma, P. T1 - Sulfonium ylides derived from 2-hydroxy-benzoquinones: crystal and molecular structure and their one-step conversion jinto Mannich bases by amine N-oxides N2 - Reaction of 2-hydroxy-para-benzoquinones with DMSO/Ac2O produced dimethylsulfonium ylides, of which crystal structures as well as solid and liquid state NMR spectra were recorded. The ylides react with tertiary methylamine N-oxides in a one-pot, multi-step process to 3-methylamino-substituted benzoquinones. The mechanism starts with a deoxygenative deprotonation of the amine N-oxides, followed by a formal electrophilic displacement of DMSO by the resulting carbonium–iminium ion. KW - Sulfonium ylides KW - Amine N-oxides KW - Crystal structure KW - Benzoquinones PY - 2004 DO - https://doi.org/10.1016/j.tet.2004.05.015 SN - 0040-4020 SN - 1464-5416 VL - 60 IS - 27 SP - 5719 EP - 5723 PB - Elsevier Science CY - Kidlington AN - OPUS4-11014 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Adorjan, I. A1 - Rosenau, Th. A1 - Potthast, A. A1 - Kosma, P. A1 - Mereiter, K. A1 - Pauli, Jutta A1 - Jäger, Christian T1 - Crystal and molecular structure of methyl 4-O-methyl-beta-D-ribo-hex-3-ulopyranoside N2 - Methyl 4-O-methyl-?-Image-ribo-hex-3-ulopyranoside (2), a model compound for partially oxidized anhydroglucose units in cellulose, was crystallized from CHCl3/n-hexane by vapor diffusion to give colorless plates. Crystal structure determination revealed the monoclinic space group P21 with Z=2C8H14O6 and unit cell parameters of a=8.404(2), b=4.5716(10), c=13.916(3) Å, and ?=107.467(4)°. The structure was solved by direct methods and refined to R=0.0476 for 1655 reflections and 135 parameters. The hexulopyranoside occurs in a distorted chair conformation. Both hydroxyls are involved in hydrogen bonding and form zigzag bond chains along the b-axis. One of the two hydrogen bonds is bifurcated. The solid-state 13C NMR spectrum of 2 exhibits eight carbon resonances, with well-separated signals for the two methoxyls (1-OMe: 55.72 ppm, 4-OMe: 61.25 ppm) and a keto resonance with relatively large downfield shift (206.90 ppm). Differences in the C-4 and the methoxyls’ chemical shifts in the solid and liquid states were found KW - Crystal structure KW - Solid-state NMR KW - Cellulose KW - Carbonyl groups PY - 2004 DO - https://doi.org/10.1016/j.carres.2004.01.006 SN - 0008-6215 SN - 1873-426X VL - 339 IS - 4 SP - 795 EP - 799 PB - Elsevier CY - Amsterdam AN - OPUS4-5341 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mackie, I.D. A1 - Röhrling, J. A1 - Gould, R.O. A1 - Pauli, Jutta A1 - Jäger, Christian A1 - Walkinshaw, M. A1 - Potthast, A. A1 - Rosenau, Th. A1 - Kosma, P. T1 - Crystal and molecular structure of methyl 4-O-methyl-beta-D-glucopyranosyl-(1->4)-beta-D-glucopyranoside N2 - The cellulose model compound methyl 4-O-methyl-?-Image-glucopyranosyl-(1?4)-?-Image-glucopyranoside (6) was synthesised in high overall yield from methyl ?-Image-cellobioside. The compound was crystallised from methanol to give colourless prisms, and the crystal structure was determined. The monoclinic space group is P21 with Z=2 and unit cell parameters a=6.6060 (13), b=14.074 (3), c=9.3180 (19) Å, ?=108.95(3)°. The structure was solved by direct methods and refined to R=0.0286 for 2528 reflections. Both glucopyranoses occur in the 4C1 chair conformation with endocyclic bond angles in the range of standard values. The relative orientation of both units described by the interglycosidic torsional angles [? (O-5?---C-1?---O-4---C-4) -89.1°, phi (C-1?---O-4---C-4---C-5) -152.0°] is responsible for the very flat shape of the molecule and is similar to those found in other cellodextrins. Different rotamers at the exocyclic hydroxymethyl group for both units are present. The hydroxymethyl group of the terminal glucose moiety displays a gauche–trans orientation, whereas the side chain of the reducing unit occurs in a gauche–gauche conformation. The solid state 13C NMR spectrum of compound 6 exhibits all 14 carbon resonances. By using different cross polarisation times, the resonances of the two methyl groups and C-6 carbons can easily be distinguished. Distinct differences of the C-1 and C-4 chemical shifts in the solid and liquid states are found. KW - Crystal structure KW - Cellulose KW - Methyl cellobioside KW - Solid state NMR PY - 2002 DO - https://doi.org/10.1016/S0008-6215(01)00299-3 SN - 0008-6215 SN - 1873-426X VL - 337 IS - 2 SP - 161 EP - 166 PB - Elsevier CY - Amsterdam AN - OPUS4-11023 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Malz, Frank A1 - Yoneda, Y. A1 - Kawada, T. A1 - Mereiter, K. A1 - Kosma, P. A1 - Rosenau, T. A1 - Jäger, Christian T1 - Synthesis of methyl 4'-O-methyl-beta-D-cellobioside-13C12 from D-glucose-13C6. Part 2: Solid-state NMR studies KW - Cellodextrins KW - Cellulose KW - Model compounds KW - Solid-state NMR KW - Glycosidic bond KW - C-13 isotopic labeling PY - 2007 SN - 0008-6215 SN - 1873-426X VL - 342 IS - 1 SP - 65 EP - 70 PB - Elsevier CY - Amsterdam AN - OPUS4-14450 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yoneda, Y. A1 - Mereiter, K. A1 - Jäger, Christian A1 - Brecker, L. A1 - Kosma, P. A1 - Rosenau, T. A1 - French, A. T1 - Van der Waals versus Hydrogen-Bonding Forces in a Crystalline Analog of Cellotetraose: Cyclohexyl 4'-O-Cyclohexyl Beta-D-Cellobioside Cyclohexane Solvate KW - Cellobioside KW - Cellotetraose KW - Cellulose KW - Solid state NMR PY - 2008 DO - https://doi.org/10.1021/ja805147t SN - 0002-7863 SN - 1520-5126 VL - 130 SP - 16678 EP - 16690 PB - American Chemical Society CY - Washington, DC AN - OPUS4-18915 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -