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'Structure Activity Correlations' in keywords
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1985 (1)
1982 (1)
1Author    Alfred Gieren, Michail KokkinidisRequires cookie*
 Title    Structure Investigations of Agonists of the Natural Neurotransmitter Acetylcholine, III [1 ] X-Ray Structure Analysis of (2-Ethoxyethyl)trimethyl- ammonium Chloride  
 Abstract    To elucidate the structure-activity correlations we have performed an X-ray structure analysis of the title compound (1), which is a muscarinic agonist o f the natural neurotransmitter acetyl­ choline. 1 crystallizes in the monoclinic space group P 2)/n with 2 molecules per asymmetric unit. Lattice parameters are: a = 10.375(6), 6 = 12.468(5), c = 15.274(17) A; /?= 95.32(7)°. The structure was solved by direct methods and refined to an /?-value o f 0.14 for 1828 observed reflections. Both cations in the asymmetric unit are disordered. In the crystal structure at least four conformations of the cation occur, indicating a pronounced conformational flexibility o f the neurotransmitter cation. The anions are arranged stereospecifically with respect to the quaternary trimethylammonio methyl group. The geometry of triangles which are defined by a nitrogen o f the quaternary ammonium group and an ether oxygen on one hand and an anion occupying a specific type of tetrahedral faces of a (CH3)3N +-C H 2 group on the other hand, is characteristic for muscarinic agonists if they contain an ether or ester oxygen in the analogous position to the ester oxygen of acetylcholine. 
  Reference    Z. Naturforsch. 37c, 977 (1982); received May 19/June 30 1982 
  Published    1982 
  Keywords    X-Ray Structure Analysis, Neurotransmitter, Conformational Flexibility, Structure-Activity Correlation 
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 TEI-XML for    default:Reihe_C/37/ZNC-1982-37c-0977.pdf 
 Identifier    ZNC-1982-37c-0977 
 Volume    37 
2Author    Jean-M Arc, D. Ucruet, Rene ScallaRequires cookie*
 Title    Action of Methylthiopyrimidine Experimental Herbicides as Diuron-Like Inhibitors of Photosynthesis  
 Abstract    Derivatives of 6-chloro-5-methylthiopyrimidines provide potent inhibitors of the photosynthe­ tic electron flow, which act like Diuron on fluorescence induction kinetics and competitively displace it from its binding site. Structure-activity relationships show that, unlike triazines, ac­ tivities of 2-or 4-alkylamino derivatives are restricted by steric hindrances. Decreases in inhibit­ ory activities of these compounds observed in triazine-resistant chloroplasts are lower than de­ creases reported for triazines themselves. 
  Reference    Z. Naturforsch. 40c, 388 (1985); received October 31 1984/February 1 1985 
  Published    1985 
  Keywords    Methylthiopyrimidines, Diuron-Like Inhibitors, Photosynthesis, Structure-Activity Correlations, Photosystem II 
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 TEI-XML for    default:Reihe_C/40/ZNC-1985-40c-0388.pdf 
 Identifier    ZNC-1985-40c-0388 
 Volume    40