TY  - JOUR
A1  - Tacke, R.
A1  - Strecker, M.
A1  - Sheldrick, W. S.
A1  - Heeg, E.
A1  - Berndt, B.
A1  - Knapstein, K. M.
T1  - Sila-Pharmaka, 14. Mitt. Darstellung und Eigenschaften sowie Kristall-und Molekülstruktur von Sila-Difenidol
JF  - Zeitschrift für Naturforschung B
N2  - 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) Å, 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 Å is observed. The anticholinergic, histaminolytic and musculotropic spasmolytic activities of 6 a and 6 b are reported.
KW  - sila-difenidol
KW  - syntheses
KW  - crystal structure
KW  - molecular structure
KW  - biological activity
Y1  - 1979
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-128391
VL  - 34
IS  - 9
ER  - 
TY  - JOUR
A1  - Waelbroeck, M.
A1  - Camus, J.
A1  - Tastenoy, M.
A1  - Lambrecht, G.
A1  - Mutschler, E.
A1  - Kropfgans, M.
A1  - Sperlich, J.
A1  - Wiesenberger, F.
A1  - Tacke, R.
A1  - Christophe, J.
T1  - Thermodynamics of antagonist binding to rat muscarinic \(M_2\) receptors: antimuscarinics of the pridinol, sila-pridinol, diphenidol and sila-diphenidol type
JF  - British Journal of Pharmacology
N2  - 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.
KW  - entropy
KW  - binding
KW  - M2 muscarinic receptors
KW  - thermodynamics
KW  - van 't Hoff plot
KW  - enthalpy
Y1  - 1993
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-128439
VL  - 109
IS  - 2
ER  - 
TY  - JOUR
A1  - Tacke, M.
A1  - Schuberth, W.
A1  - Becker, Charles R.
A1  - Haas, L. D.
T1  - The dielectric constant of PbTe at 4.2 K and \(\tilde ν\)=84.15 cm\(^{-1}\), 96.97 cm\(^{-1}\), 103.60 cm\(^{-1}\)
N2  - 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.
Y1  - 1982
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-30821
ER  - 
TY  - JOUR
A1  - Tacke, Reinhold
A1  - Bentlagem, A.
A1  - Towart, R.
A1  - Meyer, H.
A1  - Bossert, F.
A1  - Vater, W.
A1  - Stoepe, K.
T1  - Sila-Analoga von Nifedipin-ähnlichen 4-Aryl-2.6-dimethyl-1.4-dihydropyridin-3.5-dicarbonsäure-dialkylestern, I
N2  - no abstract available
KW  - Chemie
Y1  - 1980
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-82430
ER  -