| | 41 | Author
| W. S. Sheldrick, W. Trowitzsch | Requires cookie* | | | Title
| Stereochemistry and Tautomerism of Amino Acid Antagonists: a,/-Diketo Acids and Esters and their Cyclisation Products  | | | | Abstract
| a,y-Diketo Acids and Esters, Amino Acid Antagonists, Enol Forms, X-Ray Structure X-ray structural analyses of two a,y-diketo esters and one a,y-diketo acid, which are amino acid antagonists, have shown them all to be present in the solid state in the a,ß-unsaturated y-keto enolic form. The structures of the esters /3-acetyl-pyruvic acid methyl ester (1) and 2-oxo-cyclopentyl-glyoxylic acid ethyl ester (3) are stabilized by intra-molecular O---H(-O) hydrogen bonds involving the enol proton. In the case of camphor oxalic acid (4) an intramolecular O --H-O hydrogen bond between the y-keto oxygen and the acid proton is observed. The bond lengths and angles in 1 indicate a significant contribution from the mesomeric ß,y-unsaturated enol form. For comparison purposes the structure of the y-enol methyl ether of 1, (4-methoxy-2-oxo-pentene)carboxylic acid methyl ester (2) has also been determined. The X-ray structures of the cyclization products of respectively an a,y-diketo acid and an a,y-diketo ester are reported. | | | |
Reference
| Z. Naturforsch. 38b, 220—225 (1983); received June 16 1982 | | | |
Published
| 1983 | | | |
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| default:Reihe_B/38/ZNB-1983-38b-0220.pdf | | | | Identifier
| ZNB-1983-38b-0220 | | | | Volume
| 38 | |
| 42 | Author
| Ulrich Bayer, HansAlbert Brune | Requires cookie* | | | Title
| Untersuchungen zur reduktiven Eliminierung des Biphenyl-Systems aus substituierten cis-Bis(phenyI)bis(triphenylphosphan)platin(II)-Verbindungen On the Reductive Elimination of the Biphenyl System from Substituted ci6-Bis(phenyl)bis(triphenylphosphane)platinum(II) Compounds | | | | Abstract
| The Compounds cw-[Pt(PPh3)2(4-X-C6H4)2] [X = F, Cl, CF3, OCH3, N(CH3)2] and cis-[Pt(PPh3)2(4-X-C6H4)(Y-C6H4)] [X = F/Y = 3 Cl, 4-C1, 3-CH30, 4-CH30; X = CF3/Y = 3-F, 4-F] have been synthesized and studied thermally with respect to the reductive elimination of disubstituted biphenyls. Activation parameters A H+ and A S+ are reported and discussed. | | | |
Reference
| Z. Naturforsch. 38b, 226—236 (1983); eingegangen am 27. Oktober 1982 | | | |
Published
| 1983 | | | |
Keywords
| Platinum-organic Compounds, Syntheses, Reductive Elimination, Activation Parameters | | | |
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| default:Reihe_B/38/ZNB-1983-38b-0226.pdf | | | | Identifier
| ZNB-1983-38b-0226 | | | | Volume
| 38 | |
| 43 | Author
| Manfred Gerlach, Peter Jutzi, Johannes-Peter Stasch, Horst Przuntek | Requires cookie* | | | Title
| Synthese und pharmakologische Eigenschaften von silylierten Dopaminen und 4.4-Diphenylpiperidinen Synthesis and Pharmacological Properties of Silylated Dopamines and 4,4-Diphenylpiperidines | | | | Abstract
| Syntheses for the bis-O-trimethylsilylated (2), the tris-0,0,N-trimethylsilylated (3) and the tetrakis-0,0,N,N-trimethylsilylated dopamine (4) are described. The preparation of some N-trialkylsilylated 4,4-diphenylpiperidines 6-8 and of the N-triphenylsilylated piperidine 9 is also reported. The silylation of these neuropharmaca enhances their lipo-philic character. Preliminary pharmacological investigations show the desired central effect of these compounds. The silylated dopamines 3 and 4 influence positively the rigid akinetic syndrom, which was induced by reserpine. The silylated 4,4-diphenylpiperidines 6-9 show the same effect on the content of neurotransmitters in the rat brain as the Anti-parkinson drug l-ier£-butyl-4,4-diphenylpiperidine (budipine). | | | |
Reference
| Z. Naturforsch. 38b, 237—242 (1983); eingegangen am 1. Oktoder 1982 | | | |
Published
| 1983 | | | |
Keywords
| Silylated Dopamines, Silylated 4, 4-Diphenylpiperidines, Syntheses, Pharmacological Properties, Neuropharmaca | | | |
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| default:Reihe_B/38/ZNB-1983-38b-0237.pdf | | | | Identifier
| ZNB-1983-38b-0237 | | | | Volume
| 38 | |
| 45 | Author
| Reinhold Wintersteiger, OttoS. Wolfbeis | Requires cookie* | | | Title
| Two New Reagents for the Fluorescence Derivatization of NH and OH Containing Compounds | | | | Abstract
| Heterocyclic Synthesis, Fluorescence Derivatization The synthesis of three new reagents, namely the bromomethyl derivatives of a pyrano-[3,2-c]benzopyran (2b) and of llH-pyrido[l,2-b]quinazolin-ll-one (3b, d) is described. Introduction of the reactive bromomethyl group was accomplished in one case (2 b) by a ring closure reaction using ethyl y-chloroacetoacetate, and in the other cases (3 b, d) by bromination of a methyl group using N-bromosuccinimide. 2 b is suitable for the deri-vatization of barbiturates, whilst 3d reacts with oxygen nucleophiles like alcohols, phenols or carboxylates. | | | |
Reference
| Z. Naturforsch. 38b, 248—250 (1983); received October 18 1982 | | | |
Published
| 1983 | | | |
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| default:Reihe_B/38/ZNB-1983-38b-0248.pdf | | | | Identifier
| ZNB-1983-38b-0248 | | | | Volume
| 38 | |
| 47 | Author
| Hans Geiger, Harald Homberg | Requires cookie* | | | Title
| Fluoreszenz und Struktur von Flavonen, II Der Einfluß von Hydroxygruppen in 6-, 8-und 2'-Stellung* Fluorescence and Structure of Flavones, II The Influence of Hydroxy Groups at Positions 6, 8 and 2' | | | | Abstract
| The fluorescence spectra of various 2'-, 6-and 8-hydroxy-, methoxy-, and glucosyloxy-flavones adsorbed on cellulose alone and with added shift reagents are reported. The correlation between fluorescence and structure of these compounds is discussed. | | | |
Reference
| Z. Naturforsch. 38b, 253—257 (1983); eingegangen am 21. September 1982 | | | |
Published
| 1983 | | | |
Keywords
| Flavonoids, Fluorescence Spectra, Structure | | | |
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| default:Reihe_B/38/ZNB-1983-38b-0253.pdf | | | | Identifier
| ZNB-1983-38b-0253 | | | | Volume
| 38 | |
| 48 | Author
| Frank Kübel, Joachim Strähle | Requires cookie* | | | Title
| Crystal Structure of Polymerie Bis(dimethylglyoximato)pyrazine Iron (II) a | | | | Abstract
| Bis(dimethylglyoximato)pyrazine-iron(II), Crystal Structure Bis(dimethylglyoximato)pyrazine-iron(II), (dmgH)2Fepyz, crystallizes isotypicly with the Co(II) compound (dmgH^Copyz in the space group C2/m, the lattice constants being a = 1407, b = 680.0, c = 919 pm, 125.6°, Z = 2. The structure was determined using the powder pattern. It shows planar (dmgH^Fe moieties which are polymerized via axially bonded, bridging pyrazine ligands to form a linear chain of symmetry 2/m. The distance Fe-N = 200 pm in the chain is considerably shorter than in (dmgH)2Copyz (Co-N = 224 pm), since the latter has one extra electron in an antibonding orbital. | | | |
Reference
| Z. Naturforsch. 38b, 258—259 (1983); eingegangen am 20. Oktober 1982 | | | |
Published
| 1983 | | | |
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| default:Reihe_B/38/ZNB-1983-38b-0258_n.pdf | | | | Identifier
| ZNB-1983-38b-0258_n | | | | Volume
| 38 | |
| 50 | Author
| Albert Von Itter, Fritz Vögtle, Gabriela Weber, GeorgeM. Sheldrick | Requires cookie* | | | Title
| Franz | | | | Abstract
| Crown Ether (Diphenylmethano-), X-Ray The new [18]crown-5 ligand -[18] <05-(2,2')-diphenylmethano-24-coronand-5> [1] -, con-taining a benzylic CH2 group, was prepared by condensation of 2,2'-dihydroxydiphenylmethane with tetraethylene glycol dichloride. The ligand exhibits an endo-conformation and short O • • • H2C contacts. The macrocycle ligates Na + by contracting its cavity so that its five O atoms form an approximately regular pentagon. | | | |
Reference
| Z. Naturforsch. 38b, 262—264 (1983); received September 24 1982 | | | |
Published
| 1983 | | | |
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| default:Reihe_B/38/ZNB-1983-38b-0262_n.pdf | | | | Identifier
| ZNB-1983-38b-0262_n | | | | Volume
| 38 | |
| 51 | Author
| Astrid Dorfer, KarlE. Schwarzhans | Requires cookie* | | | Title
| Complexes of Cu(I), Ag(I) and Rh(III) with Nitronylnitroxylradicals as Ligands | | | | Abstract
| Nitronylnitroxylradical Complexes, Copper(I), Silver(I), Rhodium(III) The stable free radical 4,4,5,5-tetramethyl-imidazoline-l-oxyl-2-p-pyridyl-3-oxide (LI) has been prepared and used as a ligand in copper (I), silver(I) and rhodium(III) complexes, the meta isomer (L2) as a ligand in a rhodium(III) com-plex, too. The magnetic moments and the EPR spectra of the free radicals and the complexes have been investigated. A solvent and tem-perature dependent intramolecular interaction between the radicalic ligands was found in the silver(I) complex, but in none of the complexes any intramolecular interaction between the metal ions and the unpaired electrons of the ligands could be observed. | | | |
Reference
| Z. Naturforsch. 38b, 265—267 (1983); eingegangen am 8. November 1982 | | | |
Published
| 1983 | | | |
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| default:Reihe_B/38/ZNB-1983-38b-0265_n.pdf | | | | Identifier
| ZNB-1983-38b-0265_n | | | | Volume
| 38 | |
| 52 | Author
| 0. Ch, Ch, Joseph Grobe, Nikolaos Voulgarakis | Requires cookie* | | | Title
| Atran-analoge Verbindungen des Typs Me2Si-Y-M Me2(OCH2CH2)NMe m I I V 1 ) Atrane Analogous Compounds of Type Me2Si-Y-M'Me2(OCH2CH2)NMe ! I (I) 0 CH 2 CH 2 | | | | Abstract
| Heterocyclic ring compounds of type I (compounds 9 and 10) have been prepared by condensation reactions of a,co-difunctional derivatives XMe2SiCH2M'Me2X (X = Cl, NMe2; M' — Si, Sn) with N-methyldiethanolamine using the "Dilution Principle". The starting compounds XMe2SiCH2M'Me2X are obtained by reacting XMe2SiCH2MgCl with ClM'Me2X (Scheme, Abb. 1). The existence of transanular N-*Si or N->M' interactions depends on the N-M distance and the acidity of the acceptor atoms. In order to clarify the weight of these factors acyclic analoga of compounds 9 and 10 have been prepared. In den letzten 20 Jahren wurden verschiedene anorganische Ester des Di-bzw. Triethanolamins sowie Derivate des Typs R"_3M(OCH2CH2)3N und R"_2M(OCH2CH2)2NR | | | |
Reference
| Z. Naturforsch. 38b, 269—279 (1983); eingegangen am 23. August 1982 | | | |
Published
| 1983 | | | |
Keywords
| Silatrane, Stannatrane, Transanular N-^M-Interaction, NMR Data | | | |
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| default:Reihe_B/38/ZNB-1983-38b-0269.pdf | | | | Identifier
| ZNB-1983-38b-0269 | | | | Volume
| 38 | |
| 53 | Author
| Paraskevas Aslanidis, Joseph Grobe | Requires cookie* | | | Title
| Alternativ-Liganden, XIV [1] Chelating Ligands with CE'Me2 and SiEMe2 Donor Groups | | | | Abstract
| Neue Chelatliganden des Typs (2-Me2E C6H4)Si(EMe2)Me2 (E, E == N, P, As; Me -CH3) Alternative Ligands, XIV [1] Novel Chelating Ligands of the Type (2-Me2E / C6H4)Si(EMe2)Me2 (E, E' = N, P, As; Me = CH3) | | | |
Reference
| Z. Naturforsch. 38b, 280—288 (1983); eingegangen am 27. August/11. November 1982 | | | |
Published
| 1983 | | | |
Keywords
| (E, E' = N, P, As); Synthesis, Spectroscopic Characterization (NMR, IR, MS) | | | |
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| default:Reihe_B/38/ZNB-1983-38b-0280.pdf | | | | Identifier
| ZNB-1983-38b-0280 | | | | Volume
| 38 | |
| 54 | Author
| Paraskevas Aslanidis, Joseph Grobe+ | Requires cookie* | | | Title
| Alternativ-Liganden, XV [1] Neue Liganden des Typs (4-XC6H4)SiMe(EMe2)CH2CH2E Me2 (E, E = N | | | | Abstract
| Alternative Ligands, XV [1] Novel Ligands of the Type (4-XC6H4)SiMe(EMe2)CH2CH2E'Me2 (E, E' = N, P, As; X = Cl, F; Me = CH3) | | | |
Reference
| Z. Naturforsch. 38b, 289—298 (1983); eingegangen am 1. Oktober 1982 | | | |
Published
| 1983 | | | |
Keywords
| , P, As, X = Cl, F, Me -CH3) Ligands with CE'Me2 and SiEMe2 Donor Groups (E,E' = N, P, As), Synthesis, IR-Spectra, NMR Spectra, MS Spectra | | | |
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| default:Reihe_B/38/ZNB-1983-38b-0289.pdf | | | | Identifier
| ZNB-1983-38b-0289 | | | | Volume
| 38 | |
| 55 | Author
| W. Urland, E. Warkentin | Requires cookie* | | | Title
| Darstellung and Kristallstruktur | | | | Abstract
| von [(C6H5)4As]2M(N03)5 (M = Ho, Er, Tm, Yb) Preparation and Crystal Structure of [(C6H5)4As]2M(N03)5 (M = Ho, Er, Tm, Yb) The compounds [(C6H5)4As]2M(N03)5 (M = Ho, Er, Tm, Yb) were prepared and in-vestigated by X-ray diffraction. It has been found that they are isotypic with [(CeH5)4As]2Eu(N03)5. The structure was refined by single crystal data for [(C6H5)4Asj2Er(N03)5. | | | |
Reference
| Z. Naturforsch. 38b, 299—302 (1983); eingegangen am 29. November 1982 | | | |
Published
| 1983 | | | |
Keywords
| Preparation, Pentanitrates of Lanthanides, Crystal Structure | | | |
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| default:Reihe_B/38/ZNB-1983-38b-0299.pdf | | | | Identifier
| ZNB-1983-38b-0299 | | | | Volume
| 38 | |
| 56 | Author
| Hans-Friedrich Klein, Klaus Ellrich, Dietmar Neugebauer, Olli Orama, Karl Krüger | Requires cookie* | | | Title
| Triphenylstanny]tris(trimethylphosphan)cobalt - Molekül struktur und Eigenschaften Triphenylstannyltris(trimethylphosphane)cobalt -Molecular Structure and Properties | | | | Abstract
| Potassium cobaltates K+CoLsL' -(L = MeaP, L' = N2, olefin) react with SnCl(CeHs^ or GeBr(CeH5)3 to give tetracoordinate complexes containing Co-Sn and Co-Ge bonds. Crystal and molecular structures of two single crystals were determined. They show tetrahedral molecules Co[Sn(C6Hs)3][P(CH3)3]3 in different packing order. Both tetra-coordinate compounds take up small ligands thereby completing their 18-electron valence shells in compounds Co[E(C6H5)3]L3L' (L = (CH3)3P; E = Ge, L' = CO; E = Sn, L' = CO, C2H4). A sparingly soluble paramagnetic adduct Co[Sn(C6Hs)3]L4 is believed to contain a tin-bonded phosphane. Allgemeines | | | |
Reference
| Z. Naturforsch. 38b, 303—310 (1983); eingegangen am 29. November 1982 | | | |
Published
| 1983 | | | |
Keywords
| Triphenylstannyl and Triphenylgermyl Cobalt(I) Complexes, Synthesis, Reactions, Crystal Structures, Molecular Structure | | | |
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| default:Reihe_B/38/ZNB-1983-38b-0303.pdf | | | | Identifier
| ZNB-1983-38b-0303 | | | | Volume
| 38 | |
| 57 | Author
| H. Haeuseler, A. Cansiz | Requires cookie* | | | Title
| Die quaternären Systeme ZnAl2S4-ZnGa2S4, ZnAl2S4-CdAl2S4 und ZnAl2S4-ZnAl2Se4. Röntgenographische und schwingungsspektroskopisehe Untersuchungen Investigation of the Quaternary Systems ZnAl2S4-ZnGa2S4, ZnAl2S4-CdAl2S4, and ZnAl2Se4-ZnAl2Se4 by X-Ray Diffraction and Vibrational Spectroscopy | | | | Abstract
| The quasi-binary systems Zni_a:Cda;Al2S4, ZnAl^i-zjGao.^, and ZnAl2S4(i_a;)Se4:r have been investigated by X-ray diffraction and vibrational spectroscopy. In the spinel Z11AI2S4 up to 20% of Zn can be replaced by Cd. In the two other systems, ZnAl2S4 has no detectable homogeneity range. The thiogallate phases have much broader ranges of homogeneity. The compositions of the compounds at the phase boundary of the thiogallate phase are Zno.4Cdo.6Al2S4, ZnGao.4Alx.6S4, and ZnAl2S2.8Sei.2. At approximately 950 °C ZnAl2Se4 undergoes a reversible phase transition to a wurtzite-type structure. This phase transition is also observed for the solid solutions ZnAl2S4(i_a;)Se4a; with 1.0 > x > 0.3. The FIR spectra are discussed. | | | |
Reference
| Z. Naturforsch. 38b, 311—316 (1983); eingegangen am 27. Oktober 1982 | | | |
Published
| 1983 | | | |
Keywords
| Spinel, Thiogallate Type, Wurtzite Type, FIR Spectroscopy, Solid Solution | | | |
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| default:Reihe_B/38/ZNB-1983-38b-0311.pdf | | | | Identifier
| ZNB-1983-38b-0311 | | | | Volume
| 38 | |
| 58 | Author
| Hans Bezler, Joachim Strähle | Requires cookie* | | | Title
| Über die Staudinger-Reaktion mit Tantaltetrachloridazid | | | | Abstract
| Die Kristallstruktur von Tantal(V)-(triphenylphosphinimino)tetrachlorid, Ta[NP(C6H5)3]Cl4 On the Staudinger Reaction with Tantalum Tetrachloride Azide. The Crystal Structure of Tantalum(V)(triphenyl-phosphinimino)tetrachloride, Ta[NP(C6H5)3]Cl4 Tantalum(V)-(triphenylphosphinimino)tetrachloride, Synthesis, Crystal Structure [TaCl4N3]2 reacts easily with PPh3 yielding TaCl4(NPPh3), TaCl4(NPPh3)(NHPPh3) and Tads. The latter are supposed to be products of the reaction of primarily formed TaCl4(NPPh3)2-TaCl4+ with the solvent C1CH2-CH2C1. TaCl4(NPPh3) crystallizes in the monoclinic system with the space group P2i/c. The crystal structure shows centrosym-metric dimers, in which the Ta atoms are linked together by asymmetric Cl bridges. The phosphinimino ligand is coordinated trans to the Cl bridge and causes a strong trans effect. A linear P = N = Ta group with double bonds of P = N = 159.3 and Ta = N = 180,1 pm is observed. | | | |
Reference
| Z. Naturforsch. 38b, 317—320 (1983); eingegangen am 20. Oktober 1982 | | | |
Published
| 1983 | | | |
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| default:Reihe_B/38/ZNB-1983-38b-0317.pdf | | | | Identifier
| ZNB-1983-38b-0317 | | | | Volume
| 38 | |
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