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1982 (2)
1Author    Alfred Gieren, Michail KokkinidisRequires cookie*
 Title    Structure Investigations o f Agonists o f the Natural Neurotransmitter Acetylcholine II [1| X-ray Structure Analysis o f Trimethyl(4-oxopentyl)ammonium-chloride  
 Abstract    The crystal structure of Trimethyl(4-oxopentyl)ammonium-chloride ([(C H 3) 3 N —(CH^aCOCHjJCl-) (1) was determined by an X-ray structure analysis. 1 crystallizes in the orthorhombic space group P21 21 21 with a = 10.440 (3), b = 14.600 (9), c = 6.804 (9) A and with four formula units per unit cell. The structure was solved by a Patterson and a successive Fourier synthesis. The least squares refinement yielded an R-value o f 0.064 for 1077 observed reflections. The cation o f 1 is derived from acetylcholine by replacement o f the ester oxygen with a CH2 group. It shows a potent nicotinic activity and a significant difference in conformation as compared with acetylcholine. In the crystal structure the anions are oriented stereospecifically with respect to the tetrahedron of the quaternary ammonium group. The geometry o f two triangles formed by the quaternary nitrogen atom, the oxygen atom o f the carbonyl group, and by either o f the two anions nearest to the quaternary ammonium group is characteristic for the nicotinic activity o f 1. 
  Reference    Z. Naturforsch. 37c, 282 (1982); received December 231981 
  Published    1982 
  Keywords    X-ray, Neurotransmitter, Cation-Anion Interactions, Structure-Activity Relationships 
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 TEI-XML for    default:Reihe_C/37/ZNC-1982-37c-0282.pdf 
 Identifier    ZNC-1982-37c-0282 
 Volume    37 
2Author    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