5 results
Search Results
Now showing 1 - 5 of 5
- ItemMethyl 5-chloro-2-hydr-oxy-3-(4-methoxyphenyl)-4,6-dimethylbenzoate(Chester : International Union of Crystallography, 2009) Adeel, M.; Ali, I.; Langer, P.; Villinger, A.In the title compound, C17H17ClO4, the dihedral angle between the mean planes of the two benzene rings is 65.92 (5)°. The methyl ester group lies within the ring plane [deviations of O atoms from the plane = -0.051 (2) and 0.151 (2) Å] due to an intra-molecular O - H⋯O hydrogen bond. In the crystal, molecules are held together by rather weak non-classical inter-molecular C - H⋯O hydrogen bonds, resulting in dimeric units about inversion centers, forming eight- and ten-membered ring systems as R22(8) and R2 2(10) motifs. © Adeel et al. 2009.
- ItemEthyl 4-chloro-2′-fluoro-3-hydroxy-5-methylbiphenyl-2-carboxylate(Chester : International Union of Crystallography, 2011) Adeel, M.; Langer, P.; Villinger, A.In the title compound, C 16H 14ClFO 3, the dihedral angle between the mean planes of the two benzene rings is 71.50 (5)°. Due to an intramolecular O - H⋯O hydrogen bond between the hydroxy group and the carbonyl O atom of the ethyl ester group, the ethyl ester group lies within the ring plane. The crystal structure is consolidated by intermolecular C - H⋯O and C - H⋯F interactions.
- ItemTandem dinucleophilic cyclization of cyclohexane-1,3-diones with pyridinium salts(Frankfurt, M. : Beilstein-Institut zur Förderung der Chemischen Wissenschaften, 2013) Kiamehr, M.; Moghaddam, F.M.; Mkrtchyan, S.; Semeniuchenko, V.; Supe, L.; Villinger, A.; Langer, P.; Laroshenko, V.O.The cyclization of cyclohexane-1,3-diones with various substituted pyridinium salts afforded functionalized 8-oxa-10-aza-tricyclo[7.3.1.0 2,7]trideca-2(7),11-dienes. The reaction proceeds by regioselective attack of the central carbon atom of the 1,3-dicar-bonyl unit to 4-position of the pyridinium salt and subsequent cyclization by base-assisted proton migration and nucleophilic addition of the oxygen atom to the 2-position, as was elucidated by DFT computations. Fairly extensive screening of bases and additives revealed that the presence of potassium cations is essential for formation of the product.
- ItemNMR studies and crystal structure determinations of CF3 group-containing bieyelie phenolates(Berlin : de Gruyter, 2009) Mamat, C.; Reinke, H.; Langer, P.Three new CF3-substituted bicyclic salicylate derivatives were synthesized by the TiCl4-mediated cyclization of trifluoromethyl- containing ketones with l,3-bis(silyl enol ethers) and characterized by NMR and IR, spectroscopy, mass spectrometry and elemental analysis. The crystal structures of the bicyclic derivatives have been determined by single crystal X-ray analysis. All structures exhibit hydrogen bonding. © 2009 Verlag der Zeitschrift für Naturforschung.
- ItemSynthesis of unsymmetrical bis(imidoyl)dichlorides of oxalic acid(Berlin : Walter de Gruyter, 2005) Helmholz, F.; Schroeder, R.; Langer, P.Unsymmetrical oxalic acid-bis(imidoyl)dichlorides were prepared from ethyl 2-chloro-2-oxoacetate in three steps.