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2000 (1)
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1998 (3)
1Author    Reint Eujen, Ralf HaigesRequires cookie*
 Title    Reaktionen des donorfreien (C F 3 )2Cd mit Phosphor(V)halogeniden: Difluorcarben-Einschiebungen und Direktsynthese von (C F 3)3PF2 Reactions of Donor-Free (CF3)2Cd with Phosphorus(V) Halides: Insertion of Difluorocarbene and Direct Synthesis of (CF3)3PF2  
 Abstract    Difluorocarbene which is quantitatively eliminated from donor-free bis(trifluoromethyl)-cadmium below 0 °C inserts smoothly into the P-F bonds o f PF5 to form (CF3)3PF2 in high yield. Due to the fast conversion of P-Cl bonds into P-F bonds by cadmium fluoride, PC15 forms (CF3)3PF2 as well, and a direct synthesis of (CF3)3PF2 with ca. 70 % yield starting from CdEt2, CF3I and PC15 is reported. Whereas no insertion o f CF2 into the axial bonds o f (CF3)3PF2 has been detected, reaction o f (CF3)2Cd with (CF3)3PC12 gives the new tetra-kis(haloalkyl)fluorophosphoranes (CF3)3(CF2C1)PF, (CF3)3(CFC12)PF, (CF3) 2 (CF2C1)2PF and (CF3)3(CC13)PF. The NMR spectra of these and related compounds and of their hydrolysis products (CF3)3(CF3_"Cln)PO are reported. The formation of the higher chlorinated phos­ phoranes is discussed in terms o f an isomerization mechanism presumably involving carbene elimination-reinsertion processes. 
  Reference    Z. Naturforsch. 53b, 1455—1460 (1998); eingegangen am 3. Juli 1998 
  Published    1998 
  Keywords    Phosphoranes, Trifluoromethyl Compounds, Difluorocarbene, Cadmium, NM R Data 
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 TEI-XML for    default:Reihe_B/53/ZNB-1998-53b-1455.pdf 
 Identifier    ZNB-1998-53b-1455 
 Volume    53 
2Author    Axel Lifferth3, IsabelB. Ahnera, Ut Helm, Lackner, M. Artina SchäferbRequires cookie*
 Title    Synthese und Struktur von Prolinring-modifizierten Actinomycinen des X-Typs Synthesis and Structure of Proline Ring Modified Actinomycins of the X-Type  
 Abstract    The first total synthesis o f actinomycins containing L-4-hydroxyproline (1) and the separa­ tion and NM R spectroscopic assignment o f the regioisomers X (V* and iso-X0/i (lc, le) are described. The synthetic X 0/j proves, that the oxidized proline ring of the natural actinomycins 
  Reference    Z. Naturforsch. 54b, 681—6 (1999); eingegangen am 15. Januar 1999 
  Published    1999 
  Keywords    Antibiotics, Actinomycins, Synthesis, Crystal Structure, NM R Data 
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 TEI-XML for    default:Reihe_B/54/ZNB-1999-54b-0681.pdf 
 Identifier    ZNB-1999-54b-0681 
 Volume    54 
3Author    Z. NaturforschRequires cookie*
 Title    Chiral Aryl Sulfonyl Hydantoins as Hypoglycemic Agents  
 Abstract    R osh an A h m ad 3 *, R ukhsana Jab een 3, M oham m ad Z ia-ul-H aq3, H um aira N adeem 3 H elm ut D u d d eck b, and E ugen J. V erspohl0 Some novel chiral sulfonyl hydantoin derivatives 2 a -e and 3 a -e have been prepared. p-Toluenesulfonyl chloride on treatment with L-amino acids in presence of K2C 0 3/H 20 yielded /V-(/7-toluensulfonyl-)amino acids la -e which were cyclized in presence of N H 4SCN / A c20 to afford l-(p-toluenesulfonyl)-5-substituted-2-thiohydantoins 2a-e. These compounds were oxidized with H N 0 3 to yield l-(p-toluenesulfonyl)-5-substituted hydantoins 3a-e. The enantiomeric ratios of 3 a -e were determined by 'H NM R spectroscopy using E u(hfc)3. The antidiabetic activity of 3a-d has been determined. 
  Reference    Z. Naturforsch. 55b, 203 (2000); received September 2 1999 
  Published    2000 
  Keywords    Hydantoins, Antidiabetic Activity, NM R Data 
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 TEI-XML for    default:Reihe_B/55/ZNB-2000-55b-0203.pdf 
 Identifier    ZNB-2000-55b-0203 
 Volume    55 
4Author    Bernd Wrackmeyer3, Jürgen Weidinger3, Heinrich Nöthb, Wolfgang Storchb, Thomas Seifertb, Martina VosteenbRequires cookie*
 Title    Determination of Coupling Signs 17 (119Sn, 15N ) and 2/ ( 119Sn, 117Sn) in Trimethylstannylamines  
 Abstract    The l5N-labelled trimethylstannylamines 1 -3 [(M e3Sn)3N, (M e3Sn)2NPh, (M e3Sn)2N-BCgHi4 (BCgHi4 = 9-borabicyclo[3.3.0]nonyn and the non-labelled 4, Me3 Sn-N(BC8Hi4)2 , were prepared and studied by 1H, 1 C, l5N and l9Sn NMR. The l5N ultrahigh resolution NMR spectra of 1 revealed otherwise unobserved parameters such as 2/ (15N ,S n ,'C) and the isotope induced chemical shift 2 zAl2/l3C (l5N). ll9Sn NM R spectra of 1, recorded under similar con­ ditions, also show new parameters such as V (' |ySn,N,Sn,l3C) which are not resolved in the non-labelled derivative. By using various types o f two-dimensional heteronuclear shift corre­ lations, absolute coupling signs o f l7 (l l9 Sn,15N) (all < 0) in 1 -3 were determined. By the same techniques it proved possible to confirm the negative sign o f :7(Sn,Sn) (-195.4 Hz) in 1. In contrast, the coupling constants 27(Sn,Sn) for 2 (+71.7) and 3 (+62.0) possess a positive sign. This sign inversion, observed here for the first time for apparently similar compounds, demonstrates the enormous influence o f substituents on the nature o f the lone pair o f electrons at the nitrogen atom. It also shows that these experiments for sign determinations o f coupling constants are necessary in order to interpret these data correctly. 
  Reference    Z. Naturforsch. 53b, 1494—1500 (1998); received July 30 1998 
  Published    1998 
  Keywords    Tin, Amines, NM R Data, Ultrahigh Resolution, Coupling Sign Determination 
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 TEI-XML for    default:Reihe_B/53/ZNB-1998-53b-1494.pdf 
 Identifier    ZNB-1998-53b-1494 
 Volume    53 
5Author    S. I. El-Desokya, E. M. Kandeel3, A. H. Abd El-Rahm, R. R. Ana, ShmidtbRequires cookie*
 Title    Synthesis of Pyrrolo-, Thienopyrrolo-, Benzothienopyrroloquinolines as well as Triazoloindole Derivatives  
 Abstract    Substituted pyrroloquinoline, thienopyrroloquinoline, benzothieno-pyrroloquinoline and triazoloindole derivatives have been synthesized starting from 6-amino-2,3-diphenylindole. The structures of the newly synthesized compounds and MS data. 
  Reference    Z. Naturforsch. 53b, 1216—1222 (1998); received May 4 1998 
  Published    1998 
  Keywords    Pyrroloquinoline, Triazoloindole Derivatives, NM R Data, IR Data, MS Data 
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 TEI-XML for    default:Reihe_B/53/ZNB-1998-53b-1216.pdf 
 Identifier    ZNB-1998-53b-1216 
 Volume    53