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'Conformation' in keywords Facet   Publication Year 1982  [X]
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1982[X]
1Author    Alfred Gieren, Viktor Lamm, Dieter Oesterhelt, Hans-Jörg SchludeRequires cookie*
 Title    Röntgenstrukturanalyse des 4-Keto-a//-*rcms-retinals X-ray Structure Analysis of the 4-Keto-aW-/rafts-retinal  
 Abstract    The title compound (C20H26Ü2) crystallizes in the monoclinic space group P2i/n with a = 14.761(2), 6 = 8.292(1), c = 15.210(2) Ä, /S= 102.40(1)°; Z = 4. The structure was solved by direct methods and refined by least squares to a final R-value of 0.038 for 1211 observed reflections. The crystal structure is isomorphous with that of all-trans-retinal. The cyclohexenone ring shows a half-boat conformation. The connection of the cyclo-hexenone ring and the conjugated polyene chain via a formal single C-C bond is s-cis. The torsion angle C(5)-C(6)-C(7)-C(8) amounts to 56°. For the polyene side chain the typical curvature is evident. A comparison with analogous compounds shows that details in conformation, especially at the ring side-chain connection, are induced by crystal matrix. It seems that the differences in biological activity between retinal analogous compounds are not reflected by conformational differences of the free molecules. 
  Reference    Z. Naturforsch. 37b, 1612—1622 (1982); eingegangen am 1. Juni 1982 
  Published    1982 
  Keywords    N-ray, Retinal, Conformation 
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 TEI-XML for    default:Reihe_B/37/ZNB-1982-37b-1612.pdf 
 Identifier    ZNB-1982-37b-1612 
 Volume    37 
2Author    Karl Folkers, CyrilY. Bowers, Frank Momany, KlausJ. Friebel, Teresa Kubiak, Joseph MaherRequires cookie*
 Title    Antiovulatory Potency and Conformation of an Antagonist of the Luteinizing Hormone-Releasing Hormone Having Six D-Amino Acids  
 Abstract    Thr 1 ,D-Phe 2 ,D-Trp 3 > 6 ]-LHRH was the model antagonist of LHRH, which was the basis for tho design, synthesis and bioassay of seven peptides having four, five and six D-amino acids, which resulted from three single, three double, and one triple introductions of D-amino acids in positions 4, 5 and 8 of the model. Only the analog with six D-amino acids, [N-Ac-Thr 1 ,D-Phe 2 ,D-Trp 3 ,D-Ser^D-Tyr 5 ,D-Trp 6 ,D-Arg 8 ]-LHRH, had antiovulatory activity which was higher than that of the model antagonist, i.e., 70% antiovulatory activity at 25 //g/rat compared with 50% activity at 50 //g/rat, respectively. Empirical energy calculations gave a conformational structure for [N-Ac-Thr 1 ,D-Phe 2 ,D-Trp 3 , D-Ser 4 ,D-Tyr 5 ,D-Ar£' 6 ,D-Arg 8 ]-LHRH which is similar to that calculated for previous potent antagonists. These results are a basis of new designs of antagonists having D-sub-stituents in up to ten positions toward effective inhibitors of ovulation by the parenteral and oral routes of administration. 
  Reference    Z. Naturforsch. 37b, 872—876 (1982); received February 23 1982 
  Published    1982 
  Keywords    Luteinizing Hormone-Releasing Hormone, Antagonist, Antiovulation, Conformation, Contraception [N-Ac- 
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 TEI-XML for    default:Reihe_B/37/ZNB-1982-37b-0872.pdf 
 Identifier    ZNB-1982-37b-0872 
 Volume    37