@article{TackeHengelsbergZilchetal.1989,
  author    = {Tacke, Reinhold and Hengelsberg, H. and Zilch, H. and Stumpf, B.},
  title     = {Enantioselective microbial reduction of 1,1-dimethyl-1-sila-cyclohexan-2-one with growing cells of the yeast Kloeckera corticis (ATCC 20109)},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-64010},
  year      = {1989},
  abstract  = {(R)-1,1-Dimethyl-1-sila-cyclohexan-2-ol [(R)-2] was prepared by enantioselective microbial reduction of 1,1-dimethyl-1-sila-cyclohexan-2-one (1) with growing cells of the yeast Kloeckera corticis (ATCC 20109). At a substrate concentration of 0.5 g/1 (temperature 27° C, incubation time 16 h), (R}-2 was obtained on a preparative scale in 60\% yield and with an enantiomeric purity of 92\% ee. Repeated recrystallization of the biotransformation product from n-hexane raised the enantiomeric purity to 99\% ee.},
  subject      = {Anorganische Chemie},
  language  = {en}
}
@article{LambrechtFeifelWagnerRoederetal.1989,
  author    = {Lambrecht, G. and Feifel, R. and Wagner-R{\"o}der, M. and Strohmann, C. and Zilch, H. and Tacke, Reinhold and Waelbroeck, M. and Christophe, J. and Boddeke, H. and Mutschler, E.},
  title     = {Affinity profiles of hexahydro-sila-difenidol analogues at muscarinic receptor subtypes},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-63979},
  year      = {1989},
  abstract  = {In an attempt to assess the structural requirements of hexahydro-sila-difenidol for potency and selectivity, a series of analogues modified in the amino group and the phenyl ring were investigated for their affinity to muscarinic M1- (rabbit vas deferens), Mr (guinea-pig atria) and Mr (guinea-pig ileum) receptors. All compounds were competitive antagonists in the three tissues. Their affinities to the three muscarinic receptor subtypes differed by more than two orders of magnitude and the observed receptor selectivities were not associated with high affinity. The pyrrolidino and hexamethyleneimino analogues, compounds substituted in the phenylring with a methoxy group or a chlorine atom as weil as p-fluoro-hexahydro-difenidol displayed the same affinity profile as the parent compound, hexahydro-sila-difenidol: M1 = M3 > M2 • A different selectivity patternwas observed for p-fluoro-hexahydro-sila-difenidol: M3 > M1 > M2 • This compound exhibited its highest affinity for M3-receptors in guinea-pig ileum (pA 2 = 7.84), intermediate affinity for M1-receptors in rabbit vas deferens (pA 2 = 6.68) and lowest affinity for the Mrreceptors in guinea-pig atria (pA 2 = 6.01). This receptor selectivity profile of p-fluoro-hexahydro-sila-difenidol was confirmed in ganglia (M1), atria (M2 ) and ileum (M 3 ) of the rat. Furthermore, dose ratios obtained with either pirenzepine (Mt) or hexahydrosila- difenidol (M2 and M3) and the p-fluoro analogue used in combination suggested that the antagonism was additive, implying mutual competition with a single population of muscarinic receptor subtypes. These results indicate that p-fluoro-hexahydro-sila-difenidol represents a valuable tool for characterization of muscarinic receptor subtypes.},
  subject      = {Anorganische Chemie},
  language  = {en}
}
@article{WaelbroeckTastenoyCamusetal.1989,
  author    = {Waelbroeck, M. and Tastenoy, M. and Camus, J. and Christophe, J. and Strohmann, C. and Linoh, H. and Zilch, H. and Tacke, Reinhold and Mutschler, E. and Lambrecht, G.},
  title     = {Binding and functional properties of antimuscarinics of the hexocyclium/sila-hexocyclium and hexahydro-diphenidol/hexahydro-sila-diphenidol type to muscarinic receptor subtypes},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-63944},
  year      = {1989},
  abstract  = {l In an attempt to assess the structural requirements for the musearlnie receptor selectivity of hexahydro-diphenidol (hexahydro-difenidol) and hexahydro-sila-diphenidol (hexahydro-sila-difenidol), a serles of structurally related C/Si pairs were investigated, along with atropine, pirenzepine and methoctramine, for their binding affinities in NB-OK 1 cells as well as in rat heart and pancreas. 2 The action of these antagonists at musearlnie receptors mediating negative inotropic responses in guinea-pig atrla and ileal contractions has also been assessed. 3 Antagonist binding data indicated that NB-OK 1 cells (M\(_1\) type) as weil as rat heart (cardiac type) and pancreas (glandularjsmooth muscle type) possess different muscarinic receptor subtypes. 4 A highly significant correlation was found between the binding affinities of the antagonists to muscarinic receptors in rat heart and pancreas, respectively, and the affinities to muscarinic receptors in guinea-pig atria and ileum. This implies that the musearlnie binding sites in rat heart and the receptors in guinea-pig atrla are essentially similar, but different from those in pancreas and ileum. 5 The antimuscarinic potency of hexahydro-diphenidol and hexahydro-sila-diphenidol at the three subtypes was inftuenced differently by structural modifications (e.g. quaternization). Different selectivity profiles for the antagonists were obtained, which makes these compounds useful tools to investigate further muscarinic receptor heterogeneity. lndeed, the tertiary analogues hexahydrodiphenidol (HHD) and hexahydro-sila-diphenidol (HHSiD) bad an M\(_1\) = glandularjsmooth muscle > cardiac selectivity profile, whereas the quaternary analogues HHD methiodide and HHSiD methiodide were M\(_1\) preferring (M\(_1\) > glandularjsmooth muscle, cardiac).},
  subject      = {Anorganische Chemie},
  language  = {en}
}
@article{SyldatkAndreeStoffregenetal.1987,
  author    = {Syldatk, C. and Andree, H. and Stoffregen, A. and Wagner, F. and Stumpf, B. and Ernst, L. and Zilch, H. and Tacke, Reinhold},
  title     = {Enantioselective reduction of acetyldimethylphenylsilane by Trigonopsis variabilis (DSM 70714)},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-63836},
  year      = {1987},
  abstract  = {Growing and resting cells of the yeast Trigonapsis variabilis (DSM 70714) can be used for the enantioselective reduction of the organosilicon compound acetyldimethylphenylsilane (J) to give optically active (R)-(1-hydroxyethyl)dimethylphenylsilane [(R)-2] in good yields. The enantiomeric purity of the isolated product was determined tobe 62-86\% ee depending on the substrate concentration used. Both substrate and product caused an inhibition of the reaction at concentrations higher than 0.35 and 0.5 g/1, respectively. Besides, higher substrate and product concentrations led to increased formation of the by-product 1,1,3,3-tetramethyl-1,3-diphenyldisiloxane. Considering the limiting substrate and product concentrations, it was possible to use the same biomass at least 5 times without significant loss of enzyme activity. 3-Methyl-3-phenyl-2-butanone (5) and acetyldimethylphenylgermane (7), which represent carbon and germanium analogues of 1, were also found to be accepted as substrates by Trigonapsis variabilis (DSM 70714). The reduction rates of the silicon {1) and germanium compound {7) were much higher than the transformation rate of the corresponding carbon analogue 5.},
  subject      = {Anorganische Chemie},
  language  = {en}
}