@article{TackeStreckerSheldricketal.1979, author = {Tacke, R. and Strecker, M. and Sheldrick, W. S. and Heeg, E. and Berndt, B. and Knapstein, K. M.}, title = {Sila-Pharmaka, 14. Mitt. Darstellung und Eigenschaften sowie Kristall-und Molek{\"u}lstruktur von Sila-Difenidol}, series = {Zeitschrift f{\"u}r Naturforschung B}, volume = {34}, journal = {Zeitschrift f{\"u}r Naturforschung B}, number = {9}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-128391}, pages = {1279-1285}, year = {1979}, abstract = {Sila-difenidol (6b), a sila-analogue of the drug difenidol (6a), was synthesized according to Scheme 1. 6b and its new precursors 3 and 5 were characterized by their physical and chemical properties, and their structures confirmed by elementary analyses, 1H NMR and mass spectroscopy. 6 b crystallizes orthorhombic \(P2_12_12_1\) with a = 11.523(1), b = 14.366(4), c = 11.450(1) {\AA}, Z = 4, \(D_{ber} = 1.14 gcm^{-3}\). The structure was refined to R = 0.050 for 1897 reflexions. A strong nearly linear intramolecular O-H···N hydrogen bond of 2.685 {\AA} is observed. The anticholinergic, histaminolytic and musculotropic spasmolytic activities of 6 a and 6 b are reported.}, language = {de} } @article{WaelbroeckCamusTastenoyetal.1993, author = {Waelbroeck, M. and Camus, J. and Tastenoy, M. and Lambrecht, G. and Mutschler, E. and Kropfgans, M. and Sperlich, J. and Wiesenberger, F. and Tacke, R. and Christophe, J.}, title = {Thermodynamics of antagonist binding to rat muscarinic \(M_2\) receptors: antimuscarinics of the pridinol, sila-pridinol, diphenidol and sila-diphenidol type}, series = {British Journal of Pharmacology}, volume = {109}, journal = {British Journal of Pharmacology}, number = {2}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-128439}, pages = {360-370}, year = {1993}, abstract = {1 We studied the effect of temperature on the binding to rat heart \(M_2\) muscarinic receptors of antagonists related to the carbon/silicon pairs pridinol/sila-pridinol and diphenidol/sila-diphenidol (including three germanium compounds) and six structurally related pairs of enantiomers [(R)- and (S)-procyclidine, (R)- and (S)-trihexyphenidyl, (R)- and (S)-tricyclamol, (R)- and (S)-trihexyphenidyl methiodide, (R)- and (S)-hexahydro-diphenidol and (R)- and (S)-hexbutinol]. Binding affinities were determined in competition experiments using \([^3H]\)-N-methyl-scopolamine chloride as radioligand. The reference drugs were scopolamine and N-methyl-scopolamine bromide. 2 The affinity of the antagonists either increased or decreased with temperature, van 't Hoff plots were linear in the 278-310°K temperature range. Binding of all antagonists was entropy driven. Enthalpy changes varied from large negative values (down to \(-29 kJ mol^{-1}\)) to large positive values (up to \(+ 30 kJ mol^{-1}\)). 3 (R)-configurated drugs had a 10 to 100 fold greater affinity for \(M_2\) receptors than the corresponding (S)-enantiomers. Enthalpy and entropy changes of the respective enantiomers were different but no consistent pattern was observed. 4 When silanols \((R_3SiOH)\) were compared to carbinols \((R_3COH)\), the affinity increase caused by C/Si exchange varied between 3 and 10 fold for achiral drugs but was negligible in the case of chiral drugs. Silanols induced more favourable enthalpy and less favourable entropy changes than the corresponding carbinols when binding. Organogermanium compounds \((R_4Ge)\) when compared to their silicon counterparts (R4Si) showed no significant difference in affinity as well as in enthalpy and entropy changes. 5 Exchange of a cyclohexyl by a phenyl moiety was associated with an increase or a decrease in drug affinity (depending on the absolute configuration in the case of chiral drugs) and generally also with a more favourable enthalpy change and a less favourable entropy change of drug binding. 6 Replacement of a pyrrolidino by a piperidino group and increasing the length of the alkylene chain bridging the amino group and the central carbon or silicon atom were associated with either an increase or a decrease of entropy and enthalpy changes of drug binding. However, there was no clear correlation between these structural variations and the thermodynamic effects. 7 Taken together, these results suggest that hydrogen bond-forming OH groups and, to a lesser extent, polarizable phenyl groups contribute significantly to the thermodynamics of interactions between these classes of muscarinic antagonists and \(M_2\) muscarinic receptors.}, language = {en} } @article{TackeSchuberthBeckeretal.1982, author = {Tacke, M. and Schuberth, W. and Becker, Charles R. and Haas, L. D.}, title = {The dielectric constant of PbTe at 4.2 K and \(\tilde ν\)=84.15 cm\(^{-1}\), 96.97 cm\(^{-1}\), 103.60 cm\(^{-1}\)}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-30821}, year = {1982}, abstract = {The dielectric constant of a PbTe epitaxial layer has been measured by surface wave spectroscopy using an optically pumped far-infrared laser and the technique of attenuated total reflection.}, language = {en} } @article{TackeBentlagemTowartetal.1980, author = {Tacke, Reinhold and Bentlagem, A. and Towart, R. and Meyer, H. and Bossert, F. and Vater, W. and Stoepe, K.}, title = {Sila-Analoga von Nifedipin-{\"a}hnlichen 4-Aryl-2.6-dimethyl-1.4-dihydropyridin-3.5-dicarbons{\"a}ure-dialkylestern, I}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-82430}, year = {1980}, abstract = {no abstract available}, subject = {Chemie}, language = {de} }