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81	Author	Ulrike Holzgrabe, Willy Friedrichsen, Rl-FH. Esse	Requires cookie*
	Title	Keto-Enol-Tautomerism and Configurational Isomerism of 2,6-Disubstituted 4-Piperidone-3,5-dicarboxylates [1]
	Abstract	The dialkyl 2,6-dialkylsubstituted 4-piperidone-3,5-dicarboxylates were synthesized by a M annich procedure. Depending on the substitution at the nitrogen keto-enol-tautomerism and a configurational isomerism at C 2 is observed. The structure o f the N-substituted piperi-done 24 E (C 18H 29N 0 5) has been determined by X-ray analysis: it is characterized by an enol structure o f the /?-ketoester and an axial position o f the alkyl group at C 2 and an equatorial one o f the alkyl group at C 6. The O -H -O hydrogen bond shows characteristic values o f a strong hydrogen bond. The N-unsubstituted piperidones adopt a ketone structure with the all-equatorial position o f all substituents. This stereochemistry is confirmed for other enolic and ketone analogues by N M R spectroscopic methods. To work out the reason for the different thermodynamic stabilities o f the different stereochemical structures o f N-substituted and N-unsubstituted piperidones, various semiempirical calculations were done for series o f simple pairs o f carbonyl/enol tautomers, substituted acetoacetates, oxoglutarate as well as o f syste matically varied substituted cyclohexanone, 4-oxacyclohexanone and 4-piperidone deriva tives.
	Reference	Z. Naturforsch. 46b, 1237—1250 (1991); received Novem ber 2 1990
	Published	1991
	Keywords	2, 6-Disubstituted 4-Piperidone-3, 5-dicarboxylates, High-resolution N M R, X-Ray, Theoretical Calculations
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	TEI-XML for	default:Reihe_B/46/ZNB-1991-46b-1237.pdf
	Identifier	ZNB-1991-46b-1237
	Volume	46

82	Author	Thomas Strelow, Jürgen Voss, Gunadi Adiwidjaja	Requires cookie*
	Title	Preparation and Structure of Ethyl 4-Bromo-2-(diphenylmethyIene)- 3-oxo-5,5-diphenyl-4-pentenoate
	Reference	Z. Naturforsch. 47b, 1007—7 (1992); eingegangen am 23. Dezember 1991
	Published	1992
	Keywords	2, 4-D im ethylene-l, 3-cyclobutandione, D ouble-bond Splitting, Crystal Structure
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	TEI-XML for	default:Reihe_B/47/ZNB-1992-47b-1007.pdf
	Identifier	ZNB-1992-47b-1007
	Volume	47

83	Author	Hermann Irngartingera, Jochen Lichtenthälera, Dieter Fenskeb, Gerhard Baumb	Requires cookie*
	Title	Synthesen und Strukturen von 2,5-Bis(2-arylvinyl)-l,4-benzochinonen und deren photochemisches Verhalten im Kristall Syntheses and Crystal Structures of 2,5-Bis(2-arylvinyl)-l,4-benzoquinones and their Photochemical Reactivity in the Crystalline State
	Reference	Z. Naturforsch. 48b, 1411—1418 (1993); eingegangen am 14. Mai 1993
	Published	1993
	Keywords	2, 5-D istyryl-l, 4-benzoquinones, Synthesis, Crystal Structure, Solid State Photochemistry
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	TEI-XML for	default:Reihe_B/48/ZNB-1993-48b-1411.pdf
	Identifier	ZNB-1993-48b-1411
	Volume	48

84	Author	FrankB. Itterer, S. Tefan, K. Ucken, KlausP. Langhans, O. Th, Ar Stelzer, W. S. Sheldrick	Requires cookie*
	Title	Fragmentierung und Zyklisierung disekundärer Methylenbisphosphane mit sperrigen aromatischen Resten in Fe3-und Ru3-Clustern
	Abstract	L inear O ligophosphaalkanes, X X V II [1] F rag m en tatio n and Cyclization of D isecondary M ethylenebisphosphanes with Bulky A ro m atic Substituents in F e3 and R u 3 C lusters
	Reference	Z. Naturforsch. 49b, 1223—1238 (1994); eingegangen am 8. März 1994
	Published	1994
	Keywords	D isecondary M ethylenebisphosphanes, Bulky Aromatic Substituents, Phosphinidene Fragmentation, Cyclization, 2, 3-Dihydrobenzo[b]phospholes
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	TEI-XML for	default:Reihe_B/49/ZNB-1994-49b-1223.pdf
	Identifier	ZNB-1994-49b-1223
	Volume	49

85	Author	Akinori Shiotani	Requires cookie*
	Title	Die Pd-katalysierte oxidative Kupplungsreaktion von Methylbenzoesäuremethylester The Pd-Catalyzed Oxidative Coupling Reaction of Methyl Methylbenzoates
	Abstract	The Pd-catalyzed oxidative coupling reaction of methyl o-toluate gives, in the presence of a Pd/l,10-phenanthroline(phen)/Cu catalyst, exclusively, the para-linked biphenyldicarboxy-lates 1, 2, and 3. On the other hand, the meta-linked biphenyldicarboxylates 4 and 5, were predominantly formed in a catalyst system of Pd/2,4-pentanedione(acacH)/Cu, and under similar conditions 6 and 7 were also obtained from the coupling reaction of methyl m-toluate and methyl p-toluate, respectively. A reaction scheme has been proposed.
	Reference	Z. Naturforsch. 49b, 1731—1736 (1994); eingegangen am 21. April 1994
	Published	1994
	Keywords	Coupling Reaction, Steric Influence, Palladium, 1, 10-Phenanthroline, 2, 4-Pentanedione
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	TEI-XML for	default:Reihe_B/49/ZNB-1994-49b-1731.pdf
	Identifier	ZNB-1994-49b-1731
	Volume	49

86	Author	RolfW. Saalfrank3 ', BerndH. Örner1, Stephan Recka, Jochen Nachtraba, Eva-Maria Petersb, Karl Petersb, Hans Georg Von Schneringb	Requires cookie*
	Title	Synthese und Umsetzungen von 4-Acyl/Carbamoyl-N-aryl-3-chloro- pyrrol-2,5-dionen: Kristallstruktur eines auf Wasserstoffbrückenbindungen basierenden supramolekularen Bandes [1] Synthesis and Reactions of 4-Acyl/Carbamoyl-N-aryl-3-chloro-pyrrol-2,5-diones: Crystal Structure of a Supramolecular Ribbon Based on Hydrogen Bonds [ 1]
	Reference	Z. Naturforsch. 51b, 1084—1098 (1996); eingegangen am 14. August 1995
	Published	1996
	Keywords	2, 3-Dioxo-2, 3-dihydrofurans, Pyrrol-2, 5-diones, Intermolecular H-Bridges, X-Ray
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	TEI-XML for	default:Reihe_B/51/ZNB-1996-51b-1084.pdf
	Identifier	ZNB-1996-51b-1084
	Volume	51

87	Author	FredR. Oschea, G. Ernot, H. Eckm, Anna, FrankW. Ellerb, Ekkehard Fluck0	Requires cookie*
	Title	Ein neuer Heterocyclus
	Abstract	, 2A3,4A5-[l,2,4]-O xadiphosphinin (2), als Ligand eines zw eikernigen Eisenkom plexes A New H eterocycle, 2A3,4A5-[l,2,4]-O xadiphosphinine (2), as L igand o f a Binuclear Iron C om plex Preparation and properties of a coordination compound are described, in which a carbonyl group in bis[(dicarbonyl)(/;;i-cyclopentadienyl)iron] is substituted by hitherto unknown octa-Af-methyl-2A',4A:i-[l,2,4]-oxadiphosphinine-2,4,4,6-tetramine (2). The 'H , '1P, and l3C NMR spectra are recorded and discussed in detail. The molecular structure of the iron complex 4 is described and interpreted.
	Reference	Z. Naturforsch. 51b, 1725—1731 (1996); eingegangen am 27. Juni 1996
	Published	1996
	Keywords	[l, 2, 4]-Oxadiphosphinine, Binuclear Iron Complex, NMR Spectra, X-Ray
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	TEI-XML for	default:Reihe_B/51/ZNB-1996-51b-1725.pdf
	Identifier	ZNB-1996-51b-1725
	Volume	51

88	Author	Phosphonio-Substituted Tetrahydro-, -Diphosphinines, -Azaphosphinines, Georg Jochem, Martin Schm, HeinrichN. Öth ', Alfred Schmidpeter	Requires cookie*
	Title	Phosphonio-substituierte Tetrahydro-l,3-diphosphinine un(j Tetrahy dro-1,2,6-azad i phospli in i ne
	Abstract	The bis(triphenylphosphonio)propenide cation 1 provides two reactive CH sites in 1,3-position and can be condensed with the bis(dichlorophosphanyl)methylene triphenylphos-phorane 2 or the bis(dichlorophosphanyl)aniline 3 to form cationic six-membered rings: A tetrahydro-1,3-diphosphinine (4) with three phosphonio or phosphoranediyl substituents in 2,4,6-position and a tetrahydro-1,2,6-azadiphosphinine (5) carrying two such substituents in 3,5-position. The bromide of the latter was used for an X-ray structure analysis. The P111 ring members of the cations 4 and 5 can be oxidized in two steps by elemental sulfur to give the monothioxo and dithioxo derivatives 6. 7 and 8, 9. respectively. A crystal of the mixed chloride/bromide of 8 was used for another X-ray structure analysis.
	Reference	Z. Naturforsch. 51b, 1761—1767 (1996); eingegangen am 16. August 1996
	Published	1996
	Keywords	Dichlorophosphanyl Ylides and Amines, Cyclocondensation, Phosphorus Heterocycles, 1, 3-Diphosphinines, 1, 2, 6-Azadiphosphinines
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	TEI-XML for	default:Reihe_B/51/ZNB-1996-51b-1761.pdf
	Identifier	ZNB-1996-51b-1761
	Volume	51

89	Author	Lothar Beyer	Requires cookie*
	Title	Substituierte l,2,4-Thiadiazolium-dichloroaurate(I) und -tetra- chloroaurate(III) als Reaktionsprodukte von N-Thiocarbamoyl- benzamidinen mit TetrachIorogold(III)-Verbindungen
	Abstract	Substituted 1,2,4-T hiadiazolium dichloroaurates(I) and -tetrachloroaurates(III) as Products o f the R eaction o f N -T hiocarbam oyl-benzam idines w ith Tetrachlorogold(III) Com pounds U w e Schröder3, R ainer R ichter3, Jürgen H artung3, U lrich A bram b,
	Reference	Z. Naturforsch. 52b, 620—628 (1997); eingegangen am 12. März 1997
	Published	1997
	Keywords	1, 2, 4-Thiadiazoliumchloroaurates(I/III), Synthesis, X-Ray, EM Spectra, N-Thiocarbamoylbenzamidines
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	TEI-XML for	default:Reihe_B/52/ZNB-1997-52b-0620.pdf
	Identifier	ZNB-1997-52b-0620
	Volume	52

90	Author	A. Rto, M. Aaninena, R. Ené, T. B. Oeré, Tristram Chivers0, M. Asood Parvezc	Requires cookie*
	Title	Preparation and X-Ray Structure of 4-N,N'-Bis(trimethylsilyl)- amino-3,5-diisopropylphenylselenium Trichloride
	Abstract	The reaction of SeCU or SeCF with /V,/V'-bis(trimethylsilyl)-2,6-diisopropylaniline occurs not at the nitrogen atom but by electrophilic aromatic substitution at C-4 of the phenyl ring to give [(CH3)3Si]2NC6 H2('Pr:)SeCl3, which crystallizes as the chloro-bridged dimer in the triclinic system, space group P i, a -10.2598(17), b = 13.665(3), c = 9.7838(10) A, a = 90.056(13), ß = 102.439(11), 7 = 70.922(14)°, V = 1262.3(4) A \ Z = 1. The dimer contains an essentially planar CUSe^-Cl^SeCU unit, with trans apical (Me3SihNC6H2('Pr)2 groups, resulting in approximately square pyramidal geometry at Se. The bridging Se-Cl distances are unequal at 2.587(2) and 2.749(2) A.
	Reference	Z. Naturforsch. 54b, 1170—1174 (1999); received April 22 1999
	Published	1999
	Keywords	Crystal Structure, 2, 6-Diisopropylaniline, Aryl Selenium Trichloride, Bridging Chloride, NMR Data
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	TEI-XML for	default:Reihe_B/54/ZNB-1999-54b-1170.pdf
	Identifier	ZNB-1999-54b-1170
	Volume	54

91	Author	R. Balamurali, K.J Rajendra Prasad	Requires cookie*
	Title	A Facile Synthesis of Quino[2,3-fl]carbazoles
	Abstract	Condensation of l-oxo-l,2,3,4-tetrahydrocarba-zoles la-e and o-aminoacetophenone 2 under acid catalysis afforded a new class of quino[2,3-a]car-bazoles 3a-e in good yields. A plausible mecha nism for the product formation is also proposed.
	Reference	Z. Naturforsch. 54b, 1618—1620 (1999); received June 14 1999
	Published	1999
	Keywords	l-Oxo-l, 2, 34-tetrahydrocarbazole, o-Amino-acetophenone Condensation, Cyclisation, Aerial Oxidation
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	TEI-XML for	default:Reihe_B/54/ZNB-1999-54b-1618_n.pdf
	Identifier	ZNB-1999-54b-1618_n
	Volume	54

92	Author	Helm Ut Besl, Andreas Bresinsky, RupertH. Errm, Ann, Wolfgang Steglich	Requires cookie*
	Title	Cham onixin and Involutin, two Chemosystematical- ly Interesting Cyclopentanediones from Gyrodon livi dus (Boletales) [1]
	Abstract	The sporophores of Gyrodon lividus contain (—)-cha-monixin and (-)-involutin, indicating the close relation ship of Gyrodon to the Paxillaceae and Gyroporus.
	Reference	Z. Naturforsch. 35c, 824—825 (1980); received May 23 1980
	Published	1980
	Keywords	Gyrodon, Boletales, Chamonixin, Involutin, 2, 5-Diarylcy-clopentane-1, 3-diones, Chemosystematics
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	TEI-XML for	default:Reihe_C/35/ZNC-1980-35c-0824_n.pdf
	Identifier	ZNC-1980-35c-0824_n
	Volume	35

93	Author	R. Schmitt, H. Sanderm	Requires cookie*
	Title	Specific Localization of /J-D-Glucoside Conjugates of 2,4-Dichlorophenoxyacetic Acid in Soybean Vacuoles
	Reference	Z. Naturforsch. 37c, 772—777 (1982); received May 17 1982
	Published	1982
	Keywords	2, 4-Dichlorophenoxyacetic Acid, Glycine m ax L, Plant Cell Suspension Culture, Vacuole, /?-ü-Glucosides
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	TEI-XML for	default:Reihe_C/37/ZNC-1982-37c-0772.pdf
	Identifier	ZNC-1982-37c-0772
	Volume	37

94	Author	WalterA. Priitz	Requires cookie*
	Title	Tyrosine Oxidation by NOi in Aqueous Solution
	Abstract	Nitrogen dioxide, formed by y-radiolysis in deaerated aqueous nitrate/nitrite solutions, is capable of oxidizing Gly-Tyr in favourable competition with the natural decay of N 0 2 by dimerization and disproportionation. 2,2'-Biphenolic tyrosine dimers and nitro-tyrosine were identified spectroscopically as stable products. The results suggest that N 0 2 reacts with the peptide by electron abstraction, generating Gly-Tr phenoxyl radicals (PheO') which terminate by dimerization (2 PheO' -» 2,2'-biphenol) and N 0 2-scavenging (PheO* + N 0 2 -* • Nitro-Tyr).
	Reference	Z. Naturforsch. 39c, 725—727 (1984); received March 9 1984
	Published	1984
	Keywords	2, 2'-Biphenol, Nitrogen Dioxide, Nitro-Tyrosine, Phenoxyl Radical, Tyrosine Oxidation
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	TEI-XML for	default:Reihe_C/39/ZNC-1984-39c-0725.pdf
	Identifier	ZNC-1984-39c-0725
	Volume	39

95	Author	Kimiaki Yamano, Haruhisa Shirahama	Requires cookie*
	Title	Clitocybe acromelalga
	Abstract	A new piperidine amino acid, 2,4,5-piperidinetricarboxylic acid (11) was isolated from the poisonous mushroom, Clitocybe acromelalga. The structure determination and its biogenetic potential are discussed.
	Reference	Z. Naturforsch. 49c, 707 (1994); received July 7/August 15 1994
	Published	1994
	Keywords	Clitocybe acromelalga, Toadstool, Piperidine Amino Acid, 2, 4, 5-Piperidinetricarboxylic Acid, Biogenesis
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	TEI-XML for	default:Reihe_C/49/ZNC-1994-49c-0707.pdf
	Identifier	ZNC-1994-49c-0707
	Volume	49

96	Author	Jürg En, Jacob, G. Ottfried, R. Aab	Requires cookie*
	Title	2,3-Dihydroxy Fatty Acids-Containing Waxes in Storks (C iconiidae)
	Abstract	Uropygial gland secretions from five out of a total of seven species forming the genus Ciconia (family Ciconiidae; order Ciconiiformes) were found to consist of mixtures of monoester waxes, diester waxes, triester waxes, and triglycerides. Monoester waxes were com posed of unbranched fatty acids and alcohols, whereas diester waxes derived from both 2-and 3-hydroxy fatty acids esterified with unbranched alcohols and fatty acids. Interestingly, triester waxes were also found deriving from either 2-hydroxy alkylmalonic acids or from erythro-2,3-dihydroxy fatty acids the latter of which have not yet been found in vertebrates so far. To compare the typical mass spectrometric fragmentation of this class of compounds eryr/?/-o-2,3-dihydroxyhexadecanoic acid has been synthesized.
	Reference	Z. Naturforsch. 51c, 743—749 (1996); received June 7/July 1 1996
	Published	1996
	Keywords	2, 3-Dihydroxy Fatty Acids, Uropygial Gland Secretion, Triester Waxes, Ciconiiform Birds
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	TEI-XML for	default:Reihe_C/51/ZNC-1996-51c-0743.pdf
	Identifier	ZNC-1996-51c-0743
	Volume	51

97	Author	Christine Kamperdick3, Günter Adam3, NguyenHong Vanb, TranVan Sungb	Requires cookie*
	Title	Chemical Constituents of Madhuca pasquiery
	Abstract	Four triterpenoids, the scarce nortriterpenoid platanic acid, two flavonoids and 2,4-dihy-droxy phenylacetic acid methyl ester, hitherto unknown as a natural product, were isolated from Madhuca pasquiery. The structures were established by means of mass and NMR spectroscopy.
	Reference	Z. Naturforsch. 52c, 295 (1997); received D ecem ber 12 1996/February 12 1997
	Published	1997
	Keywords	Madhuca pasquiery, 2, 4-Dihydroxy Phenylacetic Acid Methyl E ster, Platanic Acid, Triterpenoids, Flavonoids
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	TEI-XML for	default:Reihe_C/52/ZNC-1997-52c-0295.pdf
	Identifier	ZNC-1997-52c-0295
	Volume	52

98	Author	M. Veith	Requires cookie*
	Title	Cyclische Diazastannylene, II 1 Intermolekulare Lewis-Säure-Base-Addukte bei 1.3.2.4A 2 -Diazasilastannetidinen Cyclic Diazastannylenes, II 1 Intermolecular Lewis-Acid-Base Adducts of 1, 3,2,4A 2 -Diazasilastannetidines
	Abstract	-diazasilastannetidines can be prepared as mono-mers (organyl = <erf-butyl) or dimers (organyl = isopropyl) in nonpolar solvents, depending on the organic nitrogen substituent. The formation of the dimer, which is due to an intermolecular Lewis-acid-base interaction of Sn(II) with nitrogen, can be initiated by solidification. When the tertf-butyl compound is cooled below 0 °C two crystalline modi-fications are found: a monoclinic phase (C 2/c; a= 10.655(5); b = 24.75(1); c = 17.334(9) Ä; ß = 106.9(1)°) and a triclinic phase (P I; a = 10.68(1); b = 13.51(1); c = 12.36(1) A; a = 96.2(1); ß = 102.6(1); y = 118.4(1)°). The crystal structures turn out to be built of dimeric and monomeric units in the first case and presumably only dimeric species in the second case. The isopropyl derivative crystallizes in the space group P 2i/b (a = 10.77(1); b= 12.14(2); c = 11.15(2) A; ß = 120.2(2)°) with only dimeric units being present, as in the liquid. Interrelationships between the three structures are discussed.
	Reference	(Z. Naturforsch. 33b, 1—6 [1978]; eingegangen am 5. September/6. Oktober 1977)
	Published	1978
	Keywords	Diazastannylenes, Solid State, X-ray, Crystal Structure, NMR l, 3-Diorganyl-2, 2-dimethyl-I, 3, 2, 4A 2
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	TEI-XML for	default:Reihe_B/33/ZNB-1978-33b-0001.pdf
	Identifier	ZNB-1978-33b-0001
	Volume	33

99	Author	George Sosnovsky, Maria Konieczny	Requires cookie*
	Title	Utilization of the Sterically Hindered Base, 4-Hydroxy-2,2,6,6-tetramethylpiperidine, as a Hydrogen Halide Acceptor
	Reference	Z. Naturforsch. 33b, 792—796 (1978); received March 17 1978
	Published	1978
	Keywords	Dehydrobromination, Preparation of Alkenes, Quaternization of Amines, Sterically Hindered Bases, 4-Hydroxy-2, 2, 6, 6-tetramethylpiperidine
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	TEI-XML for	default:Reihe_B/33/ZNB-1978-33b-0792.pdf
	Identifier	ZNB-1978-33b-0792
	Volume	33

100	Author	MohamedHilmy Elnagdi, Mohamed Ezzat, KamalUsef Kandeel, Sadek	Requires cookie*
	Title	Reactions with Cyclic Amidenes III: Synthesis of Some New Fused Pyrazole Derivatives
	Reference	Z. Naturforsch. 34b, 275—279 (1979); received August 28 1978
	Published	1979
	Keywords	Diazobetaienes, Dipolarcycloaddition, Pryazolo[4, 3-c]-l, 2, 3, 4-tetrazines, Ethoxycarbonyl Isothiocyanate, X H NMR
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	TEI-XML for	default:Reihe_B/34/ZNB-1979-34b-0275.pdf
	Identifier	ZNB-1979-34b-0275
	Volume	34

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