bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthese von D‐ und L‐S‐Auro‐1‐thio‐xylit
Authors: Wirz P. , StanêK J. , Hardegger E. 
Published: December 2004

AbstractAusgehend von S‐Benzyl‐1, 2‐O‐isopropyliden‐5‐thio‐α‐D‐xylose (Ia) wurde durch Abspaltung der Isopropylidengruppe, Reduktion und Acetylierung 2,3,4,5‐Tetra‐O‐acetyl‐S‐benzyl‐1‐thio‐L‐xylit (IV) hergestellt, der, mit Natrium in flüssigem Ammoniak entbenzyliert, über das Acetylderivat IVb zum 1‐Thio‐L‐xylit (IV c) führte. IV c wurde als krist. Octaacetyl‐disulfid V charakterisiert und in S‐Auro‐1‐thio‐L‐xylit (IV d) umgewandelt. – Dieselbe Reaktions‐folge mit den enantiomeren Verbindungen führte zum S‐Auro‐1‐thio‐D‐xylit (VI a).
Zur Konstitution des Pigment Red 177
Authors: Manukian B. K. , Mangini A. 
Published: December 2004

AbstractAuf Grund von Elementaranalyse sowie VIS.‐, IR.‐, NMR.‐ und Massen‐Spektroskopie wird dem Pigmentfarbstoff Colour Index Pigment Red 177 die Struktur des 4,4′‐Diamino‐1, 1′‐di‐anthrachinonyls zugeschrieben.
Synthese und Umlagerungsreaktionen von 2‐(2‐Amino‐anilino)‐2‐imidazolin‐Derivaten
Authors: Härter H. P. , Stauss U. , Schindler O. 
Published: December 2004

AbstractThe nitro‐imidazolines V and VI are formed by addition reaction of ethylenediamine to the isothiocyanates III and IV. The nitro group is then converted by hydrogenation to the amino group, giving XI and XII, which can be acylated selectively to IX and X. By rearrangement in boiling xylene, the compounds XI and XII give the corresponding 2‐(2‐aminoethylamino)‐benzimidazoles XIII and XIV. The benzoylated derivative IX gives the benzimidazole derivative XVIII by rearrangement and subsequent migration of the benzoyl group, while the benzylated derivative XVI gives the rearranged benzimidazole XXII. The benzimidazole structure of the rearranged products is proven by unambiguous synthesis of XIII, starting with 2‐chlorobenzimidazole (VII) and mono‐N‐acetyl‐ethylene‐diamine to give compound VIII, from which XIII is obtained by hydrolysis.
Zur Konfiguration von zwei isomeren rac.‐Cassansäure‐Derivaten.3. Mitteilung über Cassain‐Analoga
Authors: Hauth H. , Stauffacher D. 
Published: December 2004

AbstractCatalytic hydrogenation of cassenic and isocassenic acid derivatives (1 resp. 2) led to a mixture of the two isomers 3 and 4, which could be separated. The structures of these isomers were confirmed.
Echanges isotopiques d'hydrogène T‐H, T‐D, D‐H et H‐D de la diazoacétone et du diazoacétaldéhyde: Vitesse de protonation et effets isotopiques. Communication préliminaire
Authors: Dahn H. , Malherbe R. , Beaud P. 
Published: December 2004

AbstractThe velocities of four acid‐catalysed hydrogen isotope exchange reactions between diazoacetone (1) and water (T → H, T → D, D → H, and H → D) and of three exchange reactions between diazoacetaldehyde (2) and water (T → H, T → D, and H → D) have been measured. The exchange D → H of 1 was found to be submit to general acid catalysis (αB = 0.6). The rates of protonation of primary and secondary diazocarbonyl compounds of similar structure were found to be quite similar, in spite of difference in mecanism (A‐2 and A‐SE2, respectively).
Infrared Spectra of α‐Thenoyl‐trifluoroacetonates of Metal Ions of the First Transition Series
Authors: Shephard G. S. , Thornton D. A. 
Published: December 2004

AbstractThe IR. spectra of α‐thenoyl‐trifluoroacetone (HTTA) and seventeen of its chelates with metal(II) and ‐(III) ions of the first transition series have been determined. Three series of complexes are represented: the anhydrous metal(II) species, [M(TTA)2]n (M  Ca, Mn, Co, Ni, Cu, Zn); metal(II) dihydrates, [M(TTA)2(H2O)2] (M  Mn, Fe, Co, Ni, Zn); and the metal(III) chelates, [M(TTA)3] (M  Sc, V, Cr, Mn, Fe, Ga). For each metal(II) complex, the spectra of the anhydrous and hydrated compounds are practically identical, suggesting that the anhydrous complexes have the polynuclear octahedral structure established for the corresponding acetylacetonates. Magnetic moment determinations reveal that complexes of the 3d4−3d7 ions all have spin‐free configuration. Several vibrational bands with frequencies < 700 cm−1 are found to exhibit a frequency variation with d‐orbital population which is consistent with the order of crystal field stabilization energies and hence with their assignment as coupled metal‐oxygen stretching modes. Unique features of the spectra of [Cu(TTA)2] and [Mn(TTA)3] are ascribed to structural differences arising from Jahn‐Teller distortion. Tentative assignments for the majority of the ligand vibrations are given.
Spectroscopic Evidence for Symmetry‐Restricted π‐Interaction in Vanadyl β‐Keto‐enolates
Authors: Haigh J. M. , Thornton D. A. 
Published: December 2004

AbstractTheoretical treatments of the distorted square pyramidal co‐ordination observed in vanadyl β‐keto‐enolates predict restricted interligand conjugation and minimal π‐interaction in the oxovanadium‐ligand bonds. The effects of ligand substitution on the vibrational and electronic spectra of vanadyl β‐keto‐enolates yield evidence that strong σ‐bonding and ionic contributions are chiefly responsible for the strong vanadium‐ligand bonding.
Etude des composés d'addition des acides de Lewis ‐ XXXV. Note sur les composés d'addition entre amides et, respectivement, PdCl2 et PtCl2
Authors: Gioria J. M. , Susz B. P. 
Published: December 2004

AbstractThe adducts of dimethylformamide, diethylformamide, dimethylacetamide and diethylacetamide with PdCl2 and PtCl2 have been prepared and the IR. spectra of the compounds in nujol mull or in CH2Cl · CH2Cl solution are studied. The lowering of the carbonyl frequency (amide I) shows that the metal is linked by a dative bond to the amide oxygen atom acting as a donor; the lowering is about 33 to 59 cm−1.The decrease of the frequency of the carbonyl group vibration, observed in these cases as for other addition compounds of Lewis acids, is due to an intramolecular electronic displacement in the direction of the amid oxygen atom.
Die elektronische Struktur einfacher Stickstoff‐und sauerstoffhaltiger Verbindungen
Authors: Kuhn J. , Hug W. , Geiger R. , Wagnière G. 
Published: December 2004

AbstractA general review is given of the UV.‐spectroscopic properties of some simple molecules containing the NβN and NβO bond, respectively. The electronic structure of nitrosomethane, azomethane, trimethylamine oxide, azomethane N,N'‐dioxide, nitromethane, methyl nitrite are reinvestigated by the SCF‐CI method, within the frame of the all‐valence CNDO procedure. These calculations confirm a number of older assignments, but also allow predictions concerning some not settled questions. For instance, nitroalkanes should exhibit not one but two n–π* transitions, namely at 275 nm and around 350 nm. This prediction agrees with conclusions by Djerassi and co‐workers on the spectra of some nitrosteroids.Particular attention is given to the symmetry and relative energetic position of nonbonding orbitals. The question of “ basicity” and “ease of protonation” is discussed in relation to it. Calculations on the overall charge distribution complement this investigation.
Thermisches Verhalten von 1‐Acylbenzocyclobutenen; eine neue Isochromensynthese
Authors: Hug R. , Hansen H.‐J. , Schmid H. 
Published: December 2004

Abstract1‐Acyl‐benzocyclobutenes (8, 9, 10), on heating in diluted decane solution at 175–185°, rearrange to the corresponding 3‐substituted isochromenes (11, 12, 13).
Die Umsetzung protonierter Alkene mit Thioäthern: Eine neue Methode zur Darstellung von Sulfoniumverbindungen
Authors: Bosshard H. 
Published: December 2004

AbstractThioethers reacted with protonated alkenes yield quantitatively alkylsulfonium salts. The rate of the reaction is dependent on the proton activity of the medium and characterized by a maximum which is determined by the protonation of the nucleophile (thioether). The reaction is following the rule of Markownikoff.
Surface chemistry of polymers. The adsorption of carbon dioxide and sulfur dioxide on polyvinylidene chloride
Authors: Stoeckli H. F. 
Published: December 2004

AbstractIsotherms for the adsorption of nitrogen (77 K), carbon dioxide (195–247 K) and sulfur dioxide (254–293 K) on polyvinylidene chloride have been measured volumetrically. The B.E.T. cross‐sectional areas of 18 Å2 (CO2) and 24 Å2 (SO2) are comparable to liquid density values. The isosteric heat of adsorption of CO2 is constant for 0.2 < θ < 0.4 and is lower than the latent heat of condensation. For SO2, the two are practically identical up to the monolayer. Entropy calculations show ‘supermobility’ in the case of CO2.
Participation π dans la solvolyse des diazocétones primaires. Communication préliminaire
Authors: Malherbe R. , Tam Nguyen Thi Thanh , Dahn H. 
Published: December 2004

AbstractIn the acid catalyzed hydrolysis of 5,6‐unsaturated diazoketones of suitable geometry (Ib, IIb, IIIb, IVb, VIb), participation of the double bond in the reaction of the diazonium ion is proved (a) by the formation of cyclisation products, and (b) in some cases by the acceleration of the rate determining SN2 substitution process. In the case of VIb the substitution step is so much accelerated that the pre‐equilibrium protonation step becomes rate determining (evidence: inversion of the kinetic solvent isotope effect).
Photoelectron Spectra of Azabenzenes and Azanaphthalenes: III. The orbital sequence in methyl‐ and trimethylsilyl‐substituted pyridines
Authors: Heilbronner E. , Hornung V. , Pinkerton F. H. , Thames S. F. 
Published: December 2004

AbstractThe ionization potentials of methyl‐, t‐butyl‐ and trimethylsilyl‐substituted pyridines have been determined by high‐resolution photoelectron spectroscopy. The results are discussed in terms of destabilizing inductive and stabilizing conjugative effects of the substituents, and have been parametrized on the basis of a HMO‐type perturbation treatment. Our data are in accord with the idea that the topmost occupied orbital in pyridine is a ‘lone pair’ orbital.
Utilisation d'ylides du phosphore en chimie des sucres. XI. Synthèse des quatre didésoxy‐3, 5‐méthyl‐3‐pentoses parl'intermédiaire de sucres insaturés ramifiés
Authors: Tronchet J. M. J. , Graf R. 
Published: December 2004

AbstractTreated with methylthiomethylenetriphenylphosphorane, 5‐deoxy‐1,2‐O‐iso‐propylidene‐β‐D‐threo‐ and ‐α‐D‐erythro‐furanos‐3‐uloses led with good yields to a mixture of the cis‐trans isomers of the corresponding methylthiovinylidenic sugars. There was no inversion of configuration at C(4) with the thero‐furanosulose and a small one (7%) with its erythro isomer. These unsaturated branched‐chain thio‐sugars are useful synthetic intermediates. For examples, the desulfurization‐hydrogenation (Raney Nickel) of each of these alkenes afforded in good yield two 3‐deoxy‐3‐C‐methyl‐pentoses epimeric at C(3) and having the same configuration at C(4) as the starting alkenes. In all cases the isomer formed by attack from the less hindered face of the double bond was the preponderant one.
Arbeiten über Phosphorsäure‐ und Thiophosphorsäureester mit einem heterocyclischen Substituenten. 3. Mitteilung. Thiadiazol‐Ringschluss und eine dabei auftretende Methylübertragung
Authors: Rüfenacht K. 
Published: December 2004

AbstractMethods for the synthesis of 5‐alkoxy‐ and 5‐alkylthio‐1,3,4‐thiadiazol‐2(3H)‐ones and ‐thiones, known in principle, are extended and adapted for large scale preparations.In the particular case of 5‐methoxy‐1,3,4‐thiadiazol‐2(3H)‐thione the cyclisation of thiocarbazic O‐methyl ester using alcoholic alkali and carbon disulfide added in this order surprisingly yields by transmethylation 5‐methylthio‐1,3,4‐thiadiazol‐2(3H)‐one, isomer of the expected 5‐methoxy‐1,3,4‐thiadiazol‐2(3H)‐thione. This latter compound is obtained when the reactants are applied in the inverse sequence. A possible mechanism for this behaviour is presented.
Nucleosides and Nucleotides. Part 2: Synthesis of both anomers of 1‐(5′‐O‐phosphoryl‐2′‐deoxy‐D‐ribofuranosyl)‐2(1H)‐pyridone [1]
Authors: Séquin U. , Tamm Ch. 
Published: December 2004

AbstractThe two anomeric 1‐(2′‐deoxy‐D‐ribofuranosyl)‐2(1H)‐pyridones 6 and 7 were synthesized from 2‐pyridone and 3,5‐di‐(O‐p‐toluoyl)‐2‐deoxy‐D‐ribofuranosyl chloride (2) via the di‐O‐p‐toluoyl derivatives 3 and 4 using the mercuric halide procedure. Phosphorylation of the nucleosides 6 and 7 by bis‐(2,2,2‐trichloroethyl)‐chlorophosphate gave the phosphate esters 8 and 9 together with some 2‐(bis‐[2,2,2‐trichloroethyl]‐phosphoryloxy)‐pyridine 10, which proved to be very labile. Structure and configuration of compounds 6 to 9 were established by spectral methods, the configurations being derived from the chemical shifts of the sugar protons and the splitting patterns of the anomeric protons (‘triplet‐quartet rule’). The specific rotations of 3, 4, 6, 7, 8 and 9 show that the three pairs of anomers represent exceptions to Hudson's rule of isorotation.Reductive removal of the trichloroethyl groups in 8 and 9 with zinc proceeds stepwise, yielding the phosphoro‐diesters 13 and 14 and the two desired anomeric 5′‐nucleotides 15 and 16. These latter were purified and characterised as the ammonium salts.Enzymatic cleavage by the 5′‐nucleotidase of Crotalus adamanteus venom took place only in the ‘natural’ β‐series. The ‘unnatural’ α‐anomers were resistent to the enzyme.The structure of 10 was established by spectral methods and confirmed by synthesis.
Terpene Compounds as Drugs, XVI. Characterization of the anabolic 19‐nortestosterone 17β‐trans, trans‐ and ‐cis, trans‐homofarnesate
Authors: Pala G. , Mantegani A. , Zugna E. , Gallazzi A. , Vanoni P. C. 
Published: December 2004

Abstract19‐Nortestosterone 17β‐trans, trans‐ and ‐cis, trans‐homofarnesate 1 and 2 have been prepared and characterized. Their structure and configuration were identified by mode of formation, elemental analyses, IR. and particularly by NMR. spectra.
Indolalkaloide aus den Blättern von Hedranthera barteri (Hook. f.) Pichon. 146. Mitteilung über Alkaloide
Authors: Naranjo J. , Hesse M. , Schmid H. 
Published: December 2004

AbstractFrom the leaves of the West African plant (Apocynaceae Hedranthera barteri) has been isolated the phenolic (−)‐desmethyl‐vobtusine (3), alongside the already known bisindole alkaloids (−)‐goziline (1) and (−)‐vobtusine (2). The new alkaloid 3 has been spectroscopically characterised and correlated with (−)‐vobtusine (2).Furthermore, the ‘monomeric’ alkaloids (−)‐hedrantherine (4) and (−)‐17‐hydroxy‐hedran‐therine (5) were found in the leaves of H. barteri. Both of these alkaloids contain a cyclic semiacetal group. These bases and their derivatives possessing an unchanged β‐anilinoacrylester group show, in the mass spectrometer, the same characteristic fragmentation as vincadifformine (11), whilst their 2,3‐dihydroderivatives bear more of a resemblance to aspidospermine. From the strongly negative Cotton effect of 4 and 22 at 300–350 nm follows the absolute configuration in these bases of centre 12.Hedrantherine (4) represents the lower half of the bisindole type of vobtusine bases. The upper half has previously been encountered in form of the alkaloid beninine in the rootbark of H. barteri.
Nachbargruppeneffekte bei massenspektrometrischen Fragmentierungsreaktionen: substituierte 1,3‐Diaminopropan‐Derivate. 17. Mitteilung über das massenspektrometrische Verhalten von Stickstoffverbindungen
Authors: Lerch Elsbeth , Hesse M. 
Published: December 2004

AbstractThe mass spectrometric behaviour of the 1,3‐diaminopropane derivative 4a (3,7‐diacetyl‐3,7‐diazadodecane) was investigated with regard to the fragmentation reactions of N, N′, N″‐triacetylspermidine (1), as model for the 1,3‐diaminopropane part. It was established that the degradation reactions in 4a and 1 are essentially the same and mainly due to the interaction of two N‐acetyl groups. Thereby it is established that the most important mass spectrometric fragmentation reactions of spermidine derivatives take place within the 1,3‐diaminopropane unit and are independent of the influence of further N‐atoms in the molecule. An ion (m/e 143) was found in the fragmentation pattern of N, N′, N″‐triacetylspermidine whose formation can be explained by interaction of all three N‐acetyl groups. The corresponding ion was not found, in the spectrum of 4a, with only two N‐acetyl groups, thereby confirming the earlier hypothesis.
Sur l'acylation des mäthylfluorànes V. Formylation selon Rieche du mäthy1‐1‐fluoráne
Authors: Chardonnens Louis , Noël François 
Published: December 2004

AbstractThe formylation of 1‐methylfluorene according Rieche yields 1‐methyl‐2‐fluorene‐carbaldehyde, the constitution of which being proved by three independent ways.
Dipolmoment und Konformation von Imino‐äther‐Derivaten
Authors: Exner O. , Schindler O. 
Published: December 2004

AbstractBy means of the dipole moments of several imidic acid esters the conformation at the CO bond and the configuration at the CN bond have been determined. Use was made of the graphical comparison of a phenyl‐derivative with the para‐substituted analogue [7] in combination with cyclic model compounds having forced stereochemistry. The results obtained are conclusive for the N‐alkyl‐derivatives which are in the Eap form A. The imidic acid esters which are unsubstituted at the nitrogen are prevailingly in the same Eap conformation A; another conformation, probably the Zap form B, may also be present in smaller amounts.
Nucleoside und Nucleotide. Teil 3. Über die Polykondensation von Thymidin‐3′‐phosphat nach der Triestermethode
Authors: Falk W. , Tamm Ch. 
Published: December 2004

AbstractCondensation of a mixture of 25 mole per cent of 5′‐O‐p‐methoxy‐trityl‐thymidine3′‐[(β‐cyanoethyl)phosphate] and 75 mole per cent of thymidine 3′‐[(β‐cyanoethyl)phosphate] in pyridine yielded a mixture of oligonucleotides, the largest being the pentanucleotide. It was demonstrated that longer chains are not obtained due to the formation of a C‐pyridinium‐thymidine nucleotide. For avoiding this undesired side reaction, the condensation was carried out using sym.‐collidine as solvent. The analogous side reaction was not observed, longer chains of oligonucleotide were not obtained, however.
Preparation, Properties and Structure of Phenylthionophosphine Oxide (Phenylmonothiophosphonic Anhydride), [C6H5P(S)O]3
Authors: Daly J. J. , Maier L. , Sanz F. 
Published: December 2004

AbstractInteraction of phenylthiophosphonic dichloride with H2S in the presence of triethylamine in benzene solution yields phenylthionophosphine oxide (I) which, in solution as well as in the solid state, is a trimer (Ib); an X‐ray structural analysis indicates a nearly planar sixmembered ring structure with PO bonds in the ring.
Mercaptokomplexe von Indium(III)
Authors: Tunaboylu K. , Schwarzenbach G. 
Published: December 2004

AbstractThe complexes of In(III) with thioglycolate (HOCH2CH2S−) have been investigated by pH‐metric methods. Only the mononuclear species In(SR)n(3‐n)+ (n = 1, 2, 3, 4) are formed (Fig. 1): It was difficult to obtain an accurate value for the first stability constant K1 because of the high stability of the 1:1‐complex and therefore mixtures of KCl‐KNO3 were used to keep up the ionic strength of μ = 0.1. In presence of chloride, the constants Kn are smaller because of the formation of chloro complexes and mixed complexes In(SR)nCli(3‐n‐1)+ and the stability constants of these have also been determined. The constants for the complexes without coordinated chloride can finally be obtained by an extrapolation (Fig. 2). The problem of the influence of increasing charge on the stability of various complexes of the isoelectronic 4d10 cations is discussed (Fig. 3).
Utilisation d'ylides du phosphore en chimie des sucres. XII Dérivés du D‐arabino‐hexène‐1‐tétrol‐3,4,5,6
Authors: Tronchet J. M. J. , Baehler Br. 
Published: December 2004

AbstractThe preparation of several kinds of derivatives of 1‐substituted D‐arabinc‐hex‐1‐ene‐3,4,5,6‐tetrols is described. Some of these compounds, having a ‘pseudo‐formyl’ group (CHCHCN, CHCHSO2CH3) are ‘pseudo‐aldehydo‐sugars’. Their ability to react as aldehydo‐sugars was examined in light of their 13C‐NMR. spectra which provide information on their electron density at C(1) and C(2).
Bestimmung der Verteilung von Tritiumatomen in aliphatischen Mono‐ und Dicarbonsäuren
Authors: Jordan P. , Reichen W. 
Published: December 2004

AbstractIn order to determine the distribution of tritiumatoms in non saturated alicyclic hydrocarbon molecules, a new degradation method which gives higher yields than the methods used heretofore, was developed. It is a modification of the method of Hunter‐Popjak. Results obtained with palmitic acid as test substance, and with suberic acid as degradation product of cis‐cyclooctene, are given.
Electrophilic Aromatic Substitution of Groups other than Hydrogen. Part I: Ipso Factors and Rate‐Limiting Steps in Dehalogenations by Diazonium Ions. 26th communication on diazo coupling reactions
Authors: Fischer P. B. , Zollinger H. 
Published: December 2004

AbstractThe rates of substitution of the group X in 1‐X‐2‐naphthol‐6‐sulfonic acids (X = H, Cl, Br, and I) by p‐chlorobenzenediazonium ions in aqueous solution have been measured. The rates of the halogenated naphthols relative to that of the parent compound (X = H) are 0.0070:0.0089:0.149 for X = Cl, Br, and I respectively. The reaction of 1‐bromo‐2‐naphthol‐6‐sulfonic acid is catalysed by thiosulfate ions; the relative rate observed for this compound does not, therefore, represent the ipso factor. It is postulated that in its substitution the release of the electrofugal leaving group (Br⊕) is rate‐limiting.
Note Concerning the Concepts of Reaction Numbers, Independent Reactions and Resistant Groups in Chemical Thermodynamics and Kinetics
Authors: Bauder A. , Günthard Hs. H. 
Published: December 2004

AbstractA linear algebraic characterization for sets of independent reactions, independent reaction numbers, conservation laws and resistant groups for both equilibrium and kinetic systems is suggested. Basing on the ranks of two stochiometric matrices N and M, these concepts are discussed and formulas given for setting up of independent sets of equilibrium and kinetic equations. The difference in the definition of independent reaction numbers for these two types of systems is pointed out. A brief consideration is devoted to the transformations of equilibrium and kinetic equations induced by transformation from one set of linearly independent reactions to another. Finally the conservation laws are formulated as chemical invariants within the N, M framework.
Intramolekulare Diels‐Alder‐Additionen in 6‐(But‐3‐enyl)‐6‐methyl‐cyclohexa‐2,4‐dien‐1‐on‐Systemen; eine neue Synthese von Twistanderivaten
Authors: Greuter H. , Schmid H. 
Published: December 2004

AbstractAlkylation of the sodium salt of mesitol with 2‐bromomethyl‐buta‐1,3‐diene (7) in benzene and subsequent refluxing of the reaction mixture gave 7% 2‐methylene‐3‐butenyl‐mesitylether (8), 12% 5‐methylene‐1,3,8‐trimethyl‐tricyclo[4,3,1,03,7]‐8‐decen‐2‐one (9) and 44% 9‐methylene‐1,3,5‐trimethyl‐tricyclo[4,4,0,03,8]‐4‐decen‐2‐one (10), a twistane derivative. The same procedure, when applied to the sodium salt of 2,6‐dimethyl‐4‐methoxyphenol, gave in 73% yield a 26:18:54 mixture of 2,6‐dimethyl‐4‐methoxyphenyl‐(2‐methylene‐3‐butenyl)‐ether (11), 1,3‐dimethyl‐8‐methoxy‐5‐methylene‐tricyclo[4,3,1,03, 7]‐8‐decen‐2‐one (12), and 1,3‐dimethyl‐5‐methoxy‐9‐methylene‐tricyclo[4,4,0,03, 8]‐4‐decen‐2‐one (13). The tricyclic ketones 9 and 10, or 12 and 13, were also obtained on heating 8 or 11 respectively at 176° in decane solution. Alkylation of the sodium salt of 2,6‐dimethylphenol with 3‐butenylbromide in boiling toluene gave 1,3‐dimethyl‐tricyclo[4,3,1,03,7]‐8‐decen‐2‐one (17) as the only tricyclic product in 8% yield. The structures of the twistane derivatives 10 and 13 as well as those of the ketones 9, 12 and 17 were mainly deduced from spectroscopic data. Furthermore, the ketones 10 and 13 could be converted to the twistane derivatives 20 and 22, possessing C2‐symmetry. On the other hand, compounds 9 and 17 gave only the asymmetric derivatives 18 and 21.