bluuebunny/crossref_metadata_2025_split huggingface dataset:
Zur Struktur von verbrückten Photoisomeren der Cyclodieninsektizide / Structure of Bridged Photoisomers of Cyclodiene Insecticides
Authors: Schmitzer J. , Hustert K. , Parlar H. , Körte F. 
Published: February 2015

Abstract
Asymmetrically substituted chlorinated tetrahydro-4,7-methano-1H-indanes can be bridged photochemically into two types of isomerization products. These photoisomers can be distinguished on the basis of different geminal coupling constants in their 1H NMR spectra. The structural assignment is not always certain, given only one photoisomer; it is unambiguous when both isomers are available.
Notizen: Neues Triterpenoid von Primula denticulata / New Triterpenoid from Primula denticulata
Authors: Ahmad Viqar Uddin , Najmus-Saqib Q. , Usmanghani K. , Fuchs W. , Voelter W. 
Published: February 2015

Abstract
From the alcoholic extract of the plant Primula denticulata four main compounds could be isolated by column chromatography: Pridentigenin A, B, C and D. Several spectroscopic methods and the synthesis of several derivatives allow to determine the structure of Pridentigenin B.
Verfeinerung der Struktur des Nitrids MgSiN2 - eine Neutronenbeugungsuntersuchung / A Refinement of the Structure of the Nitride MgSiN2 - a Study by Neutron Diffraction
Authors: Wintenberger M. , Tcheou F. , David J. , Lang J. 
Published: February 2015

Abstract
The tetrahedral wurtzite type structure of MgSiN2 has been refined with the help of neutron diffraction. The interatomic distances for Mg-N and Si-N are in complete agreement with the previously known values and the SiN4 tetrahedra in the structure are slightly deformed.
The Chemistry of Heteroarylphosphorus Compounds, Part 14 [1] Effects of Heteroaryl Substituents at Phosphorus on the Steric Course of Wittig Reactions of Semistabilised and Stabilised Ylides
Authors: Allen David W. , Ward Helen 
Published: February 2015

Abstract
The cis-trans ratio of the stilbenes formed in Wittig reactions of semistabilised ylides (derived from benzyltri(hetero)arylphosphonium salts in ethanolic ethoxide) with benz-aldehyde decreases markedly in the series 2-furyl >2-thienyl >phenyl > 1-methylpyrrol-2-yl. The 2-furyl group favours a greater proportion of the cis-isomer than m-trifiuoro-methylphenyl, whereas the 1-methylpyrrol-2-yl group favours a greater proportion of the trans isomer than p-methoxyphenyl. Similarly, in Wittig reactions of carbonyl-stabilised ylides with benzaldehyde and acetaldehyde, the presence at phosphorus of 2-furyl groups results in a significant increase in the proportion of the cis-alkene compared to that formed from the related triphenylphosphonium ylide.
These results are discussed in terms of both betaine and cycloaddition mechanisms for the Wittig reaction. Also discussed is their relevance to recent proposals concerning the elimination of alkene from the intermediate oxaphosphetan.
Ternäre Natriumphasen mit Cadmium bzw. Quecksilber und Zinn bzw. Blei/Ternary Sodium Phases with Cadmium or Mercury and Tin or Lead
Authors: Matthes Reinhard , Schuster Hans-Uwe 
Published: February 2015

Abstract
Four ternary sodium phases with the formula Na2BX (B = Cd, Hg; X = Sn, Pb) were prepared and structurally investigated. The structures of the cubic phases Na2HgSn, Na2CdPb and Na2HgPb (space group F4̄3m) are closely related to Li3Bi, that of Na2CdSn (space group P 63mmc) to the hexagonal structure of Na3As.
Notizen: Cyclophosphazenes as Novel Antitumour Agents: Geometry of the Hexaziridinocyclotriphosphazene, N3P3Az6, from an X-ray Investigation of the Benzene Clathrate
Authors: Cameron T. Stanley , Chan Christine 
Published: February 2015

Abstract
Hexaziridinocyclotriphosphazene forms a 2:1 clathrate with benzene. The benzene makes a sandwich between the two phosphazene molecules with the planes of the rings parallel. The geminal aziridinyl groups have a most unusual eclipsed conformation.
Thermische Zersetzung nichtstöchiometrischer Cäsium-Silber-Gold(III)-Chloride und Darstellung von Mischkristallen zwischen Cs2AgAuCl6 und Cs2AuIAuIIICl6 / Thermal Decomposition of Nonstoichiometric Cesium-Silver-Gold(III)-Chloride and Preparation of Mixed Crystals of Cs2AgAuCl6 and Cs2Au<supI</supAuIIICl6
Authors: Berthold Hans Joachim , Ludwig Wolfgang 
Published: February 2015

Abstract
The thermal decomposition of cesium-silver-gold(III)-chloride Cs2Ag1-xAu1+x:/3Cl6 with 0 <x ≤ 0.63 at temperatures between 250 and 350 °C yields, under evolution of chlorine, mixed crystals of Cs2AgAuCl6 and Cs2AuIAuIIICl6. The composition of the latter can be described by the formula Cs2Ag1-y,Auy
IAuIIICl6 with y = 2x;/ (3-x). Apart from the formation of the mixed crystals the reaction leads to CsCl as a further phase, and in the case of x < 0.35 also to some Cs2AgAuCl6. Mixed crystals with 0.23 ≤ y < 1, free from additional solid phases, can be obtained from strong hydrochloric acid solutions of Cs2AgAuCl6 and Cs2AuIAuIIICl6, which contain an excess of cesium ions. The mixed crystals are isostructural with Cs2AuIAuIIICl6 (space group I4/mmm). The variation of the lattice constants with increasing silver content confirms that the univalent silver, in contrast to the univalent gold, shows no tendency toward the formation of linear dichloro complexes. Our investigations show that the "tetragonal modification of Cs2AgAuCl6", described by Elliott and Pauling and obtained by them by heat treatment of cubic cesium-silver - gold(III)-chloride, is, in fact, CS2Ag1-y/Auy
IAuIIICl6.
Reaktionen von 2.6.15.19-Tetrathia[7.7]paracyclophan mit Schwermetallsalzen / Reactions of 2,6,15,19-Tetrahia[7.7]paracyclophane with Heavy Metal Salts
Authors: Koray Ali R. , Ziegler Manfred L. 
Published: February 2015

Abstract
2,6,15,19-Tetrathia[7,7]paracyclophane reacts with salts of the soft acids Hg2+ , Ag+, Pt2+ and Pd2+ to give polymeric complexes which are insoluble in all common solvents. As expected, no products are obtained with hard acids like Li+, Na+, K+, Rb+ and Cs+.
Anwendung der 11B-NMR-Spektroskopie zur Untersuchung von Hydroborierungen, II [1]Hydroborierung von 1.5-Cyclooctadien mit Boran in Tetrahydrofuran / Application of 11B NMR Spectroscopy to the Study of Hydroboration, II [1] Hydroboration of 1,5-Cyclooctadiene with Borane in Tetrahydrofurane
Authors: Contreras Rosalinda , Wrackmeyer Bernd 
Published: February 2015

Abstract
The existence of various intermediates in the hydroboration of 1,5-cyclooctadiene with borane in tetrahydrofurane (BH3-THF) is revealed by 11B NMR spectroscopy. The presence of the THF adduct of 9-borabicyclo[3,3,1]nonane in solutions of the dimer in THF is proved for the first time, and the importance of the adduct in accelerating exchange reactions shown by 11B NMR spectroscopy.
Phasenbeziehungen im System Ag-As-S und thermochemisches Verhalten von Ag7MX6-Verbindungen (M = P, As, Sb; X = S, Se) / Phase Relations in the System Ag-As-S and Thermal Behaviour of Ag7MX6 Compounds
Authors: Blachnik Roger , Wickel Ulrike 
Published: February 2015

Abstract
The phase relations of the ternary system Ag-As-S were established by DTA and X-ray investigations. The quasibinary sections Ag2S-Ag7AsS6 and Ag7AsS6-Ag3AsS3 are described. The system Ag-As-S contains several stable compounds, including Ag7AsS6 as a member of the Argyrodit family. The compounds Ag7PS6, Ag7AsS6, Ag7PSe6, Ag7AsSe6 und AgvSbS6 were investigated by DSC and high-temperature X-ray methods. All compounds have a phase transformation from space group P213 to F4̅3m at higher temperatures. Lattice constants and transformation temperatures are given.
Kationische Thionitrosyl-Komplexe des Chroms / Cationic Thionitrosyl Complexes of Chromium
Authors: Herberhold Max , Haumaier Ludwig 
Published: February 2015

Abstract
A nitromethane solution of NS+PF6
-, obtained in situ from N3S3Cl3 and AgPF6 (1:3), reacts with benzene tricarbonyl chromium in acetonitrile solution to give the thionitrosyl-containing salt [Cr(NS)(NC-Me)5](PF6)2 (1)-In the presence of Zerf-butyl isocyanide and Zn powder, 1 is reduced to [Cr(NS)(CN-CMe3)5F6 (3), while subsequent oxidation of 3 with either NOPF6 or AgPF6 leads to [Cr(NS)(CN-CMe3)5](PF6)2 (5). The thionitrosyl-containing salts 1, 3 and 5 are compared with the corresponding nitrosyl complexes.
Solubilization and Photoreaction of Thiazine Dyes in Reversed Micelles
Authors: Miyoshi Norio , Tomita Giiti 
Published: February 2015

Abstract
Thiazine dyes were solubilized very slowly in dodecylammonium propionate reversed micellar cyclohexanic solutions containing 0.5 M H2O. Light accelerated highly the solubilization of the dyes. The dye monomer band blue-or red-shifted by the solubilization dependent on the dye species. Thiazine dyes solubilized in the reversed micelles containing 0.1 M H2O exhibited a new absorption band at about 500 nm.
The photoreduction of thiazine dyes by allylthiourea was enhanced drastically by solubilizing the dyes in the reversed micellar solutions containing 0.5 M H2O, and the singlet oxygen production was also effectively photosensitized by the solubilized thiazine dyes. The relative quantum yields for the photoreduction of the dyes by allylthiourea and the furan oxidation by singlet oxygen produced by the photosensitization of the dyes were obtained in the reversed micellar solutions. Results obtained were discussed in connection with the solubilization.
Untersuchungen an natürlichen γ und δ-Laktonen, X [1] Synthese von Umuravumbolid und Epiumuravumbolid / Investigations on Naturally Occuring γ-and δ-Lactones, X [1] Synthesis of Umuravumbolide and Epiumuravumbolide
Authors: Achenbach Hans , Witzke Joachim 
Published: February 2015

Abstract
6-(3-Acetyloxy-1-heptenyl)-5,6-dihydro-2H-pyran-2-one (= umuravumbolide), the new α-pyrone recently isolated from leaves of the central African Iboza riparia, and its diastereomer, epiumuravumbolide, were synthesised.
Struktur-Wirkungsbeziehungen polyfunktioneller Diterpene des Tigliantyps, IV [1-3]. Derivate des Tiglians mit fehlendem oder geöffnetem Cyclopropanring und ihre irritierende und tumorpromovierende Wirkung / Structure-Activity Relationships of Polyfunctional Diterpenes of the Tigliane Type, IV [1-3]. Derivatives of Tigliane without or with Opened Cyclopropane Ring and their Irritant and Promoting Activity
Authors: Sorg Bernd , Gschwendt Michael , Thielmann Heinz Walter , Hecker Erich 
Published: February 2015

Abstract
The synthesis of the esters 6d-8d, 9 c and 10 c is described. These compounds are closely structurally related to the irritant and tumorpromoting 12-O-tetradecanoylphorbol-13-acetate (TPA, 2 a) and to phorbol-12,13-didecanoate (PDD, 2 c) except that they possess no cyclopropane ring. Biological tests show that opening or complete removal of the cyclopropane ring leads to nearly total loss of irritant or tumorpromoting (tested in the case of 9 c and 10 c) activity.
Acyl-und Alkylidenphosphane, XV 2.2-Dimethylpropylidinphosphan, eine stabile Verbindung mit einem Phosphoratom der Koordinationszahl 1/ Acyl- and Alkylidenephosphines, XV 2,2-Dimethylpropvlidynephosphine, a Stable Compound with a Phosphorus Atom of Coordination Number 1
Authors: Becker Gerd , Gresser Gudrun , Uhl Werner 
Published: February 2015

Abstract
In the presence of small amounts of solid sodium hydroxide, [2,2-dimethyl-l-(trimethylsiloxy)propylidene]-trimethylsilylphosphine reacts at + 20 °C to give hexamethyldisiloxane and 2,2-dimethylpropylidynephosphine (2). In contrast to similar alkylidynephosphines this compound is stable at room temperature. The IR and mass spectrum are discussed, and 1H, 13C and 31P NMR spectral data are given.
Perfluormethyl-Element-Liganden, XXIV Organozinnverbindungen als Reagenzien, III Spaltungsreaktionen der Element-Element-Bindung in Verbindungen des Typs RnE-ERm(R = CH3, CF3·E =P, As, Se, Te · n,m = 1, 2)/Perfluormethyl Element Ligands, XXIV ; Organotin Compounds as Reagents, III Cleavage Reactions of the Element-Element-Bond in Compounds of the Type RnE-ERm (R = CH3CF3; E = P, AS, S, Se, Te; n,m=1, 2)
Authors: Dehnert Peter , Grobe Joseph , Le Van Duc 
Published: February 2015

Abstract
A systematic study of the cleavage of element-element bonds in compounds of the type RnE-ERm (R = CH3, CF3; E = P, As, S, Se, Te; n,m = 1, 2) by the group IV A element hydrides Me3M′H (M′ = Si, Ge, Sn; Me - CH3) has been carried out. To evaluate the reaction pathway, for a number of compounds the attack of H2O, CH3OH, HBr and HI has been investigated. Possible reaction intermediates have been synthesized by independent routes and tested under comparable conditions.
Notizen: Eine nicht erwartete intramolekulare Photoreaktion eines Hexachloroctahydrodimethanonaphthalins/An Unexpected Intramolecular Photoreaction of a Hexachlorooctahydrodimethanonaphthaline
Authors: Parlar H. , Inanici Y. 
Published: February 2015

Abstract
Photoreactions of 1,2,3,4,10,10-hexachloro-6,7-epoxy-1,4,4a,5,6,7,8,8a-octahydro-1,4-endo, endo-5,8-dimethano-naphthaline (1) were studied in acetone with wavelengths above 290 nm. With the help of column chromatography an unusual isomerisation product (4) could be isolated, whose structure was established by spectral data obtained by mass spectrometry infrared spectroscopy, 1H and 13C nuclear magnetic resonance measurements.
Zur Reaktion aromatischer Phosphanderivate mit Elektronen, I. / On the Reaction of Aromatic Phosphane Derivatives with Electrons, I.
Authors: Kaim Wolfgang 
Published: February 2015

Abstract
The compounds ;p-Me2P(X)-C6H4-P(X)Me2, X = O, S, Se, NPh undergo one-electron reduction at a mercury cathode or on reaction with solvated electrons in a K/18-crown-6/THF mixture. The radical anions formed are persistent and have been characterized by ESR. They may be described as complexes of the spin-bearing moiety p-Me2P-C6H4-PMe2 · with the coordinated groups X.
(Aminoethinyl)metallierimgen, IX [1] Umsetzungen von Inaminen mit Cyanketenen / (Aminoethynyl)metallations, IX [1] Reactions of Ynamines with Cyanoketenes
Authors: Himbert Gerhard , Fachbereich Lothar Henn 
Published: February 2015

Ynamines 2 bearing methyl or phenyl groups at their C/C triple bond react with tert-butylcyanoketene 1a to give the cyclobutenones 3 and/or the allene carboxamides 4. 3 and 4 are the products of two different [2 + 2] cycloaddition reactions.
β-Silylated, β-germylated and β-stannylated ynamines 5 add the cyanoketenes 1 under "(aminoethynyl)metallation" to furnish the new enynamines 6. These compounds were characterized by IR and 1H NMR spectroscopy and partly by mass spectrometry.
The stannyl derivatives of 6 hydrolyze very easily to the corresponding acyl ynamines 7 and react with 4-nitrobenzoyl chloride to give the 1-(aminoethynyl)vinyl benzoates 8. The diazo compound 9 is formed by the interaction of tosyl azide on the enynamine 6 c, which is probably first hydrolyzed to 7a. N,N-Diethyl-N-(triphenylsilylethynyl)amine (5e) reacts with two molecules of tert-butylcyanoketene (1a) to give the allene derivative 10, probably via the corresponding enynamine 6 (R1 = R2 = Et, MR3
3 = SiPh3, R4 -tBu).
Redox Properties of Platinum Uracil "Blues": A New Type of Paramagnetic Species
Authors: Seul M. , Neubacher H. , Lohmann W. 
Published: February 2015

Abstract
The observation of a new type of ESR spectrum in the course of redox experiments on a platinum uracil "blue" compound is reported. Some characteristic features of the ESR and optical absorption spectra are described. A tentative analysis of the ESR spectrum is pre-sented, based on the assumption of localized states.
Interhalogen-Kationen: Darstellung und Kristallstrukturen (143 K) von I3Cl2SbCl6, I3Cl2AlCl4 und I3Br2SbCl6 / Interhalogen Cations: Preparation and Crystal Structures (143 K) of I3Cl2SbCl6, I3Cl2AlCl4 and I3Br2SbCl6
Authors: Pohl Siegfried , Saak Wolfgang 
Published: February 2015

Abstract
The title compounds were prepared and their crystal structures determined from low temperature single crystal X-ray data. The structures contain the anions SbCl6
- and AlCL4
-and the novel interhalogen cations I3Cl2
+ and I3Br2
+ . Anions and cations are linked to infinite chains by weak covalent bonds.
Kinetische Untersuchungen zur Wasserstoffübertragung von Dihydropyridinen auf Hydrazyle / Kinetic Investigation on the Hydrogen Transfer from Dihydropyridines to Hydrazyls
Authors: Abou-Elenien G. , Rieser J. , Ismail N. , Wallenfels K. 
Published: February 2015

Abstract
The results of a kinetic study on the hydrogen transfer between different dihydropyridines and mono-, bis-and trishydrazyls of the tricyanobenzene series are described. The reactions have been found to obey in all cases a second-order law. The influences of solvent medium, redox-potentials of the reactants and temperature on the rates of reactions have been investigated.
Tl2Sn2S5, ein Thallium(I)thiostannat(IV) mit fünffach koordiniertem Zinn / Tl2Sn2S5, a Thallium(I) Thiostannate(IV) with Fivefold Coordinated Tin
Authors: Eulenberger Günther 
Published: February 2015

Abstract
The new compound Tl2Sn2S5 was prepared by fusion of a stoichiometric mixture of the elements followed by prolonged heating at 300 °C. The compound crystallizes in the monoclinic system in space group C2/c with lattice constants a - 11.115(2), 6 = 7.723(1), c = 11.492(2) Å, and β = 108.60(1)° (Z = 4). The Sn atoms are coordinated by five S atoms forming a considerably distorted trigonal bipyramid (mean distance Sn-S: 2.497 Å). By common edges the SnS5 bipyramids are linked into chains extending in the [110] and [11̄̄0] directions, respectively. The chains are cross-linked by sharing the remaining equatorial vertices of the SnSs bipyramids, thus forming a three-dimensional framework which is related to that described for Na4Sn3S8 [1]. The Tl atoms located in channels running parallel to the b axis are surrounded by nine S atoms. The distances Tl-S vary from 3.073 to 3.897 Å.
Untersuchungen über den Verlauf der Hydrolyse einiger Borsäurealkylester und den Nachweis von Zwischenprodukten / Investigations on the Course of the Hydrolysis of Some Tris(alkoxy)boranes and the Identification of Intermediates
Authors: Steinfeldt Karl-Peter , Heller Gert , Baumert Reinhard 
Published: February 2015

Abstract
In the course of the hydrolysis of tris(alkoxy)boranes B(OR)3 (R = methyl, n-butyl, or 2-ethylhexyl) with a small amount of water in organic solvents, both possible intermediates (RO)2BOH and ROB(OH)2 have been unambiguously identified by Raman spectroscopic measurements. Lines have been found for (CH3O)2BOH at 772.8 cm -1 and for CH3OB(OH)2 at 814.6 cm -1 . The compounds are in equilibrium with the starting material B(OCH3)3 and the product B(OH)3.
Potentiometrie and conductometric investigations likewise indicate the existence of these species. A mechanism of the hydrolysis reaction is based on kinetic considerations.
With hydroxide ions in non-aqueous solvents or aqueous hydroxide ions the hydrolysis reactions occur differently because in the first case the end product of the hydrolysis is the orthoborate ion [B(OH)4]-, whereas in the second case in concentrated aqueous solutions poly borates are formed.
10B-, 11B-, 13C-NMR-Untersuchungen von closo-Pentaalkyl-1.5-dicarbapentaboranen(5) / 10B-, 11B-, 13C NMR Studies of closo-Pentaalkyl-1,5-dicarbapentaboranes(5)
Authors: Köster Roland , Wrackmeyer Bernd 
Published: February 2015

Abstract
NMR parameters [chemical] shifts (δ11B, δ13C) and coupling constants (1J(13C1H), 1J(13C11B), 1J(13C13C), 1J(11B11B) of closo-pentaalkyl-1,5-dicarbapentaboranes(5) were determinated by 10B, 11B, and 13C NMR spectroscopy. The magnitudes of 1J(13C11B) and 1J(13C13C) correspond to 1J(11B1H), 1J(13C11B) and 1J(13C1H) in the parent compound 1,5-C2B3H5 . According to predictions from MO calculations 1J(11B11B) was found to be < 10 Hz. Together with these data the δ11B and δ13C values show that neither the structure nor the bonding situation in the polyhedron are significantly affected by alkyl substitution.
Phosphate Production and Analysis in the Non-Enzymatic Activation of Amino Acids by ATP when Using Hydroxylamine as a Trapping Agent
Authors: Mullins Dail W. , Lacey James C. 
Published: February 2015

Abstract
Phosphate Production, Hydroxylamine, ATP Saygin and Decker [6, 7] have reported that the formation of hydroxamic acids in solutions containing ATP, MgCl2, hydroxylamine and an acidic acceptor (acetic acid or amino acids) is not accompanied by the release of inorganic phosphate from ATP. Using an ion exchange chromatography method developed by Lowenstein [8] to separate the various components of such reaction mixtures, we now show that inorganic phosphate, as well as some pyrophosphate, is produced during incubation at 50 °C. Evidence is also presented to indicate that the failure of Saygin and Decker [6, 7] to detect phosphate is due to a total inhibition of their phosphate assay system by ATP.
Solvent Induced Circular Dichroism in Conformational Analysis: Bile Pigments
Authors: Lehner Harald , Krauss Corinna , Scheer Hugo 
Published: February 2015

Abstract
The applicability of solvent induced circular dichroism (SICD) for the conformational analysis of bile pigments has been investigated. The S-(-)-ethyl lactate induced rotational strengths for octaethylbilindion (4) and its dihydroderivative 5 are remarkably high. Related compounds, e.g. the isomeric purpurines 1 and 2 and formyltripyrrinon 3 exhibit an optical activity which is smaller by more than one order of magnitude. 1-3 are essentially free from steric strain so that a flat arrangement of the chromophore is most likely. On the other hand the closed conformations of 4 and 5 experience considerable steric repulsion of their terminal rings, so that a helical topology is energetically favoured. This distinction is reflected in the magnitude of the SICD observed and demonstrates its applicability for the conformational analysis of bile pigments.
Elektrochemisches Verhalten der Nitrophenole und ihrer Reduktionsprodukte an Graphitelektroden/ Electrochemical Behavior of the Nitrophenols and Their Reduction Products at Graphite Electrodes
Authors: Theodoridou Elli , Jannakoudakis Dimitrios 
Published: February 2015

Abstract
The electrochemical reduction of the isomeric nitrophenols at graphite electrodes is investigated in aqueous solutions with pH = 1-13 and is compared with the electro-chemical oxidation of their reduction products. o-Nitrophenol and p-nitrophenol are reduced to the corresponding amines, as the observed oxidation peaks in their cyclic voltammograms can be simulated by those of o-and p-aminophenol. m-Nitrophenol is reduced to m-hydroxylaminophenol, as its oxidation peak appears at much more negative » potential than that of m-aminophenol, within the potential range of the oxidation of phenylhydroxylamine.
The pH-dependence of the reduction potentials of the nitrophenols at the graphite electrodes is discussed in comparison with that at a hanging mercury drop electrode.
Azulen-Naphthalin-Umlagerung. Thermolyse von [4.7-13C2] -Azulen/ Azulene-Naphthalene Rearrangement. Thermolysis of [4,7-13C2] Azulene
Authors: Zeller Klaus-Peter , Wentrup Curt 
Published: February 2015

Abstract
The mixture of 13C2-labelled naphthalenes obtained by flash vacuum thermolysis of [4,7-13C2] azulene (9) consists of [1,4-13C2]- (14) and [2,10-13C2] naphthalene (10) as major products and [1,3-13C2]naphthalene (11) as a minor product. Traces of [1,6-13C2]- (12) and [1,7-13C2] naphthalene (13) are also detectable. The recently proposed vinylidenenorcaradiene mechanism [5] correctly predicts the major products.