bluuebunny/crossref_metadata_2025_split huggingface dataset:
Valenzisomerisierung von cis‐Dienonen I. 2‐Vinyl‐3,4,5,6‐tetrahydrobenzaldehyd; Pyrolyse. von 6‐Oxabicyclo [3,1,0] hex‐2‐en [1]
Authors: Schiess P. , Chia H. L. 
Published: December 2004

AbstractThe synthesis of 2‐vinyl‐3,4,5,6‐tetrahydrobenzaldehyde (10) is described. This compound equilibrates above 70° with its valence isomer 4,5‐tetramethylene‐2H‐pyran (11) as can be shown by cis‐trans‐isomerization of the double bond in selectively deuterated 10. The unstable 2H‐pyran 11 can be trapped as tetracyanoethylene adduct 12.Gas phase pyrolysis of 6‐oxabicyclo [3.1.0] hex‐2‐ene (18) at 400°C leads to cis‐penta‐2, 4‐dienal (19) in fair yield.
Menschliches Calcitonin. V). Aufbau und Charakterisierung des geschützten Synthese‐Zwischenprodukts Calcitonin M‐(1‐10)‐decapeptid
Authors: Kamber B. , Brückner H. , Riniker B. , Sieber P. , Rittel W. 
Published: December 2004

AbstractThe present report describes in detail the synthesis and characterisation of the protected Calcitonin M decapeptide 1–10, , a key intermediate in the synthesis of Calcitonin M. I. was obtained from the openchain precursor Boc‐Cys (Trt)‐Gly‐Asn‐Leu‐Ser (But)‐Thr (But)‐Cys (Trt)‐Met‐Leu‐Gly‐OH (II) by oxidation with iodine in a yield of 70%, after purification by counter‐current distribution.II was prepared by fragment coupling of the sequences 1–4 and 5–10.The free calcitonin M (1–10)‐decapeptide, obtained from I by removal of the protecting groups by acidolysis, has no hypocalcaemic activity and does not inhibit specific binding of calcitonin M to its antibodies in rabbit serum.
Dünnschichtchromatographie als Hilfsmittel in der Radiochemie. 4. Mitteilung Trennung von 113Sn und 113mIn
Authors: Seiler H. , Seiler M. 
Published: December 2004

AbstractThin‐layer chromatography is applied to the separation of 113mIn from 113Sn. Different factors influencing migration and separation of the ions are investigated. The method can be used for the examination of the purity of isolated 113mIn solutions.
Über die Heterogenität der Aldolasen. Vorläufige Mitteilung. 17. Mitteilung über Aldolasen [1]
Authors: Gürtler B. , Leuthardt F. 
Published: December 2004

AbstractAldolase A (rabbit muscle) and aldolase B (human liver) have been resolved by isoelectric focusing into five distinct enzymatically active compounds. Each single component, if refocused under the same conditions, yields one single peak at the same isoelectric position as in the previous run. If component I or III are rehybridized (method of Penhoet et al.) component I yields one single peak, whereas component III yields the complete five membered set.Apparently the aldolases A and B are both tetrameres of two heterogeneous types of subunits α/α′ and β/β′ respectively. Analogous to the five membered set produced by hybridization of the aldolases A, B and C, the subunits α/α′ or β/β′, respectively, combine randomly to tetrameres forming five membered sets of the type α4, α3α′, α2α2′, α1α3′, α4′, etc.
Über das Alkaloid Lonicerin aus Callichilia barteri. 137. Mitteilung über Alkaloide
Authors: Naranjo J. , Hesse M. , Schmid H. 
Published: December 2004

AbstractThe alkaloid lonicerine was isolated from Callichilia barteri (Apocynaceae). By chemical and spectroscopic evidence it could be shown to be 16‐epi‐aspidodasycarpine (1).
Über die Stereochemie von Zwischenprodukten (Aldolbasen) der Doebner‐von Miller‐Chinolin‐Synthese
Authors: Schindler O. , Michaelis W. 
Published: December 2004

AbstractIn the Doebner‐von Miller quinoline synthesis with acetaldehyde or crotonaldehyde two stereoisomeric 4‐hydroxy‐1, 2, 3, 4‐tetrahydroquinaldines are formed as intermediates. The stereochemistry of these compounds differing in the relative positions of the hydroxygroups to the methyl‐group can be ascertained by NMR.‐spectroscopy. The pKa‐values of stereoisomers are not identical due to the different spacial positions of the HO‐groups.
Über Pterinchemie 30. Mitteilung [1] Die Oxydation der hydrierten Lumazine durch Luftsauerstoff und das unerwartete Verhalten der 6, 7‐Diphenyl‐5, 6‐dihydro‐pteridine in sauren Lösungen
Authors: Viscontini M. , Leidner H. 
Published: December 2004

AbstractDie hydrierten 6, 7‐Diphenyllumazine sind gegen Luftsauerstoff beständiger als die entsprechenden 6, 7‐Diphenylpteridine, werden jedoch nach einem gleichen Mechanismus oxydiert. Während die tetrahydrierten Pteridine unter intermediärer Bildung eines trihydrierten Radikals und anschliessend eines dihydrierten chinoiden Pteridins zu 7, 8‐Dihydropteridinen oxydiert werden, verläuft die Oxydation der 5, 6‐Dihydropteridine anders, In neutralen sowie in alkalischen Lösungen wird ein monohydriertes Radikal gebildet, welches dem Sauerstoff ein zweites Elektron und Proton abgibt, unter Bildung der entsprechenden Pteridine. In sauren Lösungen addiert die 7, 8‐Doppelbindung eine Molekel Wasser. Die so entstandenen hydratisierten Pteridine werden – wie die Tetrahydropteridine – viel rascher oxydiert, so dass die Oxydation der 5, 6‐Dihydropterine leichter in sauren als in neutralen Lösungen erfolgt. Das intermediäre 7‐Hydroxy‐6, 7‐diphenyl‐5, 6, 7, 8‐tetrahydrolumazin wurde als Hydrochlorid rein isoliert.
Ringschlussreaktionen von 1‐(2‐Aminophenyl)‐1‐phenyl‐äthylenen durch Kondensation mit Phosgen
Authors: Künzle F. , Schmutz J. 
Published: December 2004

AbstractCyclization of 1‐(2‐aminophenyl)‐1‐phenyl‐ethylenes or 1‐(2‐aminophenyl)‐1‐phenyl‐propenes (II) by condensation with phosgene led to 4‐phenyl‐carbostyrils (III) or 2‐chloro‐4‐phenyl‐quinolines (IV). Similarly, thiophosgene afforded 4‐phenyl‐thiocarbostyril.Treatment of 1‐(2‐aminophenyl)‐2‐methyl‐1‐p‐tolyl‐propene (VII) with phosgene led to the corresponding isocyanate IX, which cyclized in the presence of aluminum chloride with loss of a methyl group to 3‐methyl‐4‐p‐tolyl‐carbostyril (III‐6). However, 1‐(2‐aminophenyl)‐2‐methyl‐1‐phenyl‐propene (VIII) treated with phosgene gave the isocyanate XI and 3‐phenyl‐3‐isopropenyloxindole (X). Cyclization of the isocyanate XI with aluminium chloride led simultaneously to 3‐methyl‐4‐phenyl‐carbostyril (XIV), and with migration of a methyl group to 3‐methylene‐4‐methyl‐4‐phenyl‐3. 4‐dihydro‐carbostyril (XV).
ESR. Spectra of the Radical Ions of Indeno[1, 2, 3‐cd]fluoranthene
Authors: Elschenbroich Ch. , Gerson F. 
Published: December 2004

AbstractThe ESR. spectra of the radical anion and the radical cation of indeno [1, 2, 3‐cd]‐fluoranthene have been recorded. Their hyperfine structures are consistent with those expected on the basis of simple MO models.
Cycloaddition an das Tetracyclo[4.2.0.02, 8.05, 7]octan‐System [1]. Vorläufige Mitteilung
Authors: Prinzbach H. , Philippossian G. , Scheidegger U. 
Published: December 2004

AbstractThe tetracyclo [4.2.0.02, 8.05, 7]octane derivative 2 adds dienophiles (tetracyanoethylene, dimethylacetylenedicarboxylate) stereospecifically to its bishomocyclobutadiene system, yielding the adducts 5 and 6, resp.
Eine neue Synthese von Petalin
Authors: Grethe G. , Lee H. L. , Uskoković M. R. , Brossi A. 
Published: December 2004

AbstractA new synthesis of the alkaloid petaline (14), which includes a Stevens rearrangement (5→6) and the preferential O‐demethylation of 6, is described.The structures of the by‐products in the demethylation were determined by the use of nmr. and mass spectroscopy.
Alkylation des «malonyl‐α‐aminopyridines»
Authors: Urban René , Grosjean Mireille , Arnold Wolf 
Published: December 2004

AbstractThe alkylation of the ‘malonyl‐α‐aminopyridines’ (4) gives mixtures of substitution products, mainly the N1‐and O2‐alkyl derivatives. The IR., UV. and NMR. spectra are discussed.
Die Tropfzeitabhängigkeit der polarographischen Halbstufen‐potentiale von 2‐Phenylchinoxalin
Authors: Schellenberg M. 
Published: December 2004

AbstractReversible redox reactions which are followed by irreversible steps give often polarographic waves with drop life dependent shapes. A mathematical model is proposed which is capable to describe the change of the polarographic waves of quinoxalines, even at short drop lives and slow reactions of the irreversible step.
Chimie et pharmacologie de l'apiose III. Synthèse et propriétés de l'hydrate de l'O‐isopropylidène‐1, 2‐tétrosulo‐3‐furannose
Authors: Tronchet J. M. J. , Tronchet Mme J. 
Published: December 2004

AbstractRuthenium tetroxide oxidation of 1, 2‐O‐isopropylidene‐β‐D‐threofuranose affords, besides the known 1, 2‐O‐isopropylidene‐α‐L‐glycero‐tetros‐3‐ulofuranose, a lactone. The tetrosulose is easily hydrated to the corresponding gem‐diol whose dehydration on molecular sieves leads to a branched‐chain dimer. Lead tetraacetate oxidation of 1, 2‐O‐isopropylidene‐α‐L‐glycero‐tetros‐3‐ulofuranose p‐nitrophenylhydrazone leads quantitatively, to a gem‐azoacetate, a new synthetic intermediate in carbohydrate chemistry. The 3‐O‐acetyl‐1, 2‐O‐isopropylidene‐α‐L‐glycero‐tetr‐3‐enofuranose is easily obtained from the gem‐diol. A highly stereoselective procedure is described to prepare the 3‐O‐acetyl‐1, 2‐O‐isopropylidene‐α‐L‐3, 4‐exo‐D2‐erythrofuranose.
Flexional Effects in Bridged Bicyclic Molecules Progressive Flattening of Chair Cyclohexane
Authors: Jefford C. W. , Baretta A. , Fournier J. , Waegell B. 
Published: December 2004

AbstractMeasures of the progressive flattening of the chair conformation in a series of constrained cyclohexanols are obtained and compared by proton NMR. coupling constants and by molecular mechanics.
Fluorine NMR. Spectra of conformationally constrained Gem‐difluorocyclohexanes
Authors: Jefford C. W. , Hill D. T. , Ramey K. C. 
Published: December 2004

AbstractThe 19F chemical shifts and geminal coupling constants have been measured for 3,3‐dimethyl‐ (I), 3,3,5‐trimethyl‐ (II) and 3,3,5,5‐tetramethyl‐1, 1‐difluorocyclohexane (III) and 3,3‐difluorobicyclo [3.2.1]octane (IV). The Eyring parameters for the ring inversion were obtained for I and III. Representative values for the Arrhenius activation energy (Ea), ΔG‡, ΔH‡, and ΔS‡ are: 11.0, 9.4, 10.4 kcal/mole and 4.5 e.u. for I, and 10.0, 8.3, 9.7 kcal/mole and 8.3 e.u. for III. It appears that the syn‐axial methyl‐fluorine interaction has a negligible effect on the inversion process. However, the syn‐axial methyl‐methyl interaction, as found in III, significantly increases the rate of inversion. Substituent effects on the 19F shifts are marked. Introduction of methyl at C‐3 in an equatorial position leads to shielding of the equatorial and axial fluorines (+1.8 and + 1.3 ppm). Substitution in the axial C‐3 position causes deshielding of the equatorial and axial fluorines (−5.9 and −4.9 ppm).
Über Pterinchemie. 32. Mitteilung [1]. Synthese des natürlichen D‐Neopterins und L‐Monapterins
Authors: Viscontini M. , Provenzale R. , Ohlgart S. , Mallevialle J. 
Published: December 2004

AbstractBei der Kondensation von 2, 4, 5‐Triamino‐6‐oxo‐1, 6‐dihydropyrimidin mit dem Phenylhydrazon der D‐Arabinose bzw. L‐Xylose im wässerigen Methanol unter N2 und anschliessender Oxydation der Kondensationsprodukte werden D‐Neopterin bzw. L‐Monapterin gebildet. Nach Reinigung und Umkristallisation aus Wasser werden beide Substanzen als farblose Kristalle in sehr hoher Ausbeute erhalten.
Pigmente von Nereiden (Annelida, Polychaeten). 1., Vorläufige Mitteilung. Isolierung von Pterindimeren aus den Augen von Platynereis dumerilii (Audouin & Milne Edwards) 1833
Authors: Viscontini M. , Hummel W. , Fischer A. 
Published: December 2004

AbstractAus den Augen von Platynereis dumerilii wurden Neopterin und die in ihrer Struktur noch nicht vollständig aufgeklärten neuen Pterine Platynerepterin und Nerepterin isoliert. Diese zwei dunkelgelb und dunkel‐blauviolett gefärbten Pterine besitzen UV.‐Spektren, die demjenigen des Pterorhodins ähnlich sind. Ihren Eigenschaften nach sind sie sehr wahrscheinlich hydroxylierte Pterindimere. Somit wird bestätigt, dass Pterindimere in der Natur viel weiter verbreitet sind, als man hätte annehmen können. Beide Pigmente kommen ebenfalls bei anderen Nereiden als Augenpigmente vor.
Thermisches Verhalten von Mesitylallenen; Beispiel einer aromatischen [1, 5s]‐sigmatropischen H‐Verschiebung. Vorläufige Mitteilung
Authors: Heimgartner H. , Zsindely J. , Hansen H.‐J. , Schmid H. 
Published: December 2004

AbstractMesitylallene (6a), 1‐mesityl‐3‐methyl‐allene (6b) and 1‐mesityl‐3, 3‐dimethylallene (6c) were prepared via dienol‐benzene‐rearrangements. At 170° 6a isomerises to give 5, 7‐dimethyl‐1, 2‐dihydronaphthalene (8). Under the same conditions 6b rearranges to give 2, 5, 7‐trimethyl‐1, 2‐dihydronaphthalene (10; 60%) and cis‐1‐mesitylbuta‐1, 3‐diene (11; 40%) while 6c gives only cis‐1‐mesityl‐3‐methyl‐buta‐1, 3‐diene (13). The allenes undergo first an aromatic [1, 5 s]‐sigmatropic H‐shift to the o‐xylylene derivatives 7, 9 and 12, which then exhibit disrotatory ring closure to the dihydronaphthalenes or aromatic [1, 7 a]‐sigmatropic H‐shift to the 1‐mesitylbuta‐1, 3‐dienes.
Photochemische Umwandlungen. XXXIV [1]. Photochemische Isomerisierung substituierter Benzonorbornadiene
Authors: Eberbach W. , Würsch P. , Prinzbach H. 
Published: December 2004

AbstractThe benzonorbornadiene derivatives 4, 5, 6 and 19 give upon direct photoexcitation the benzo‐tricyclo [3.2.0.02, 7] heptenes 14, 17, 21 and 23 in yields up to 60%. Sensitization by acetone improves the yields considerably. The spectral data of the substrates 4, 5, 6, 7 and 19, of the photoproducts 14, 17, 21 and 23, as well as of the dihydrobenzonorbornadienes 13, 16 and 22, are presented.
Synthese und Kristallstruktur von Tetramethylammonium‐Gismondin
Authors: Baerlocher Ch. , Meier W. M. 
Published: December 2004

AbstractA new synthetic zeolite, (CH3)4NA1Si3O8, H2O, has been synthesized and shown to be an isotype of the mineral gismondine, CaAl2Si2O8,4H2O. Sodium and other cations can be introduced by ion exchange after thermal decomposition of the organic cation. A continuous structural change to «cubic» NaP has thereby been recorded, which indicates that the latter is also based on a gismondine‐type aluminosilicate framework.The crystal structure of tetramethylammonium‐gismondine has been determined using X‐ray powder data supplemented by electron diffraction. The crystals are tetragonal, a = 9.84 and c = 10.02 Å, with 4 formula units per unit cell. The apparent symmetry of the framework structure is I41/amd, however, this is violated by the organic cation. Two of the methyl groups are pointing to oxygen atoms of the framework and the short methyl‐oxygen distances indicate CH ⃛ O interaction.
Synthèses dans la série des bis‐indéno‐fluorènes, VI [1] Dihydro‐12, 15–6H‐bis‐indéno[1. 2‐b; 2′.1′‐h]fluorène et dihydro‐14, 15–8H‐bis‐indéno[2. 1‐a; 2′. 1′‐h]fluoréne
Authors: Stauner Thomas , Avar Lajos , Chardonnens Louis 
Published: December 2004

AbstractStarting from cyclohexene and 2, 2′, 5, 5′‐tetramethylbiphenyl the linear bisindenofluorene 12, 15‐dihydro‐6H‐diindeno [1.2‐b; 2′.1′‐h] fluorene (XX) has been synthesized in 5 steps (overall yield 27%). As an intermediate product the 6, 12, 15‐trioxo‐derivative XIX (greyish green crystals, blue alcaline vat) was obtained. By a side way, the 6‐oxo‐derivative of XX and the already known monoangular bis‐indenofluorene 14, 15‐dihydro‐8H‐diindeno [2.1‐a; 2′.1′ ‐h] fluorene (XXVII) were also obtained. XX can also be prepared in several steps starting from 3‐methyl‐fluorene or fluorene.
Peptide and Amide Bond Formation in Aqueous Solutions of Cyclic or Linear Polyphosphates as a possible prebiotic process
Authors: Rabinowitz Joseph 
Published: December 2004

AbstractEn faisant réagir des acides aminés en solution aqueuse, à température ordinaire et à pH env. 11, en présence de polyphosphates cycliques ou linéaires, on obtient des dipeptides avec des rendements allant jusqu'a 40%. Dans le cas de la sérine, on note uniquement la formation du dérivé O‐phosphorylé, soit l'acide sérinephosphorique.En faisant réagir un mélange de glycine (ou d'alanine) et de l'une des trois amines suivantes: phosphosérine, phosphoéthanolamine ou acide amino‐2‐éthanephosphonique, en solution aqueuse en présence de trimétaphosphate, on obtient à côté de la diglycine des quantités appréciables d'amide mixte, soit la N‐glycyl‐phosphosérine, la N‐glycyl‐phosphoéthanolamine et l'acide N‐glycyl‐amino‐2‐éthanephosphonique respectivement. Nous pensons que des peptides, phosphopeptides et amides mixtes de ce type sont également formés lors de réactions par décharge électrique dans des systèmes contenant de la phosphine, du méthane, de l'ammoniac et de l'eau.Un mécanisme probable conduisant à la liaison peptidique ou amide serait la formation intermédiare d'un acylphosphate cyclique ou ouvert de l'acide aminé, qui réagirait ensuite avec le groupe amino d'une deuxième molécule d'acide aminé (→ peptide) ou de l'amine (→ amide).Ces réactions présenteraient un certain intérêt dans la formation prébiotique de la liaison peptidique et amide, ainsi que de la liaison ester phosphorique.
3‐O‐Phosphoryl‐digitoxigenin. Partialsynthetische Versuche in der Reihe der Herzgifte, 3. Mitteilung
Authors: Sawlewicz Ludwika , Linde Horst H. A. , Meyer Kuno 
Published: December 2004

AbstractDie Bereitung von 3‐O‐Phosphoryl‐digitoxigenin (III), seines Dinatrium‐ und Piperaziniumsalzes sowie seines Dimethylesters IV wird beschrieben.
Further Examples of Steric Inhibition to Cyclopropyl Conjugation in α,β‐unsaturated esters
Authors: Jorgenson Margaret J. , Gonzenbach Hans‐Ulrich 
Published: December 2004

AbstractDas UV.‐Absorptionsmaximum des α, 7β‐ungesättigten Esterchromophors wird in Cyclopropylacrylsäureestern durch den Dreiring bathochrom um ca. 24 nm verschoben [2]. Durch die Substitution mit Methylgruppen in den γ‐(2a, b), α‐ und γ‐(3a, b) sowie β‐ und γ‐Stellungen (1a, b) wird gezeigt, dass dieser auxochrome Effekt stark von der Konformation abhängt und sogar negativ werden kann, wenn die für die Konjugation optimale bisektriche Lage von Dreiring und Doppelbindungsebene sterisch destabilisiert wird.
C‐glycosides III. Cyclo‐additions dipolaires ‐ 1,3 d'oxydes de nitriles et de nitrilimines. Communication préliminaire
Authors: Tronchet J. M. J. , Jotterand A. , Le Hong N. , Perret Melle F. , Thorndahl‐Jaccard Mme S. , Tronchet Mme J. , Chalet J. M. , Faivre Melles L. , Hausser C. , Sébastian C. 
Published: December 2004

Abstract1.3‐dipolar cycloaddition of alkenes (or alkynes) on sugars‐nitriloxides and nitrilimines led respectively to 3‐glycosyl‐isoxazolines (or isoxazoles) and 3‐glycosyl‐pyrazolines (or pyrazoles). 5‐glycosyl‐isoxazolines were similarly prepared from arylnitriloxides and α‐ or ω‐unsaturated sugars. These new C‐glycosides are potential antiviral and anti‐tumor agents.
Oxymercuration. Substituted 9‐oxabicyclo[4.2.1]‐ and 9‐ oxabicyclo[3.3.1]nonanes
Authors: Ganter C. , Wicker K. , Zwahlen W. , Schaffner‐Sabba K. 
Published: December 2004

AbstractOxymercuration of cis, cis‐1, 5‐cyclooctadiene (1), followed by treatment with potassium iodide and subsequent reaction with iodine, leads to six isomeric diiodides which represent the three possible stereoisomers 2, 3, and 4 of 2, 5‐diiodo‐9‐oxabicyclo[4.2.1]nonane as well as 5, 6, and 7 of 2, 6‐diiodo‐9‐oxabicyclo[3.3.1]nonane. The isolation, structure determination and some reactions of these diiodo compounds 2–7 are described.
The Conjugative Interaction between π‐Orbitals and Walsh‐e‐Orbitals in Bullvalene and Related Systems
Authors: Bischof P. , Gleiter R. , Heilbronner E. , Hornung V. , Schröder G. 
Published: December 2004

AbstractThe photoelectron spectra of bullvalene (1), dihydrobullvalene (2), tetrahydrobullvalene (3), hexahydrobullvalene (4), and homotropylidene (5) have been recorded. The first bands in these spectra are correlated with orbitals which are linear combinations of the Walsh‐e‐orbitals and of the olefinic π‐orbitals. This assignment is based on a qualitative ZDO‐molecular orbital model as well as on the results of extended Hückel calculations. As anticipated, a large interaction is found between the π‐ and the Walsh‐e‐orbitals in 1, 2, and 3, indicative of a resonance integral β ≈ −2 eV, i.e. of the same order as that between the two double bond π‐orbitals in butadiene (β = − 2.4 eV). In 5 the interaction between π‐ and Walsh‐e‐orbitals is negligible.
Étude comparative de la décarboxylation des acides (benzothiazolyl‐2)‐acétique, ‐3‐propionique, ‐glyoxylique et ‐pyruvique
Authors: Baudet Pierre , Otten Claude 
Published: December 2004

AbstractBenzothiazol‐2‐yl glyoxylic acid and α‐amino‐benzothiazol‐2‐yl acetic acid hydrochloride undergo decarboxylation at room temperature. This facile decarboxylation seems to depend on the following requirements: (a) the formation of a planar zwitterion; (b) a distance of about 2.2 Å between the charges of the zwitterion; (c) the stabilisation of the intermediate carbanion.In fact the following compounds which do not fulfil these three conditions do not decarboxylate at room temperature: α‐hydroximino benzothiazol‐2‐yl acetic acid, α‐amino benzothiazol‐2‐yl acetic acid as internal salt, benzothiazol‐2‐yl acetic acid, 3‐(benzothiazol‐2‐yl)‐propionic acid and benzothiazol‐2‐yl pyruvic acid.
Synthese von 2,7‐Dioxa‐isotwistan und 2,7‐Dioxatwistan. Vorläufige Mitteilung
Authors: Ganter C. , Wicker K. 
Published: December 2004

AbstractThe syntheses of 2,7‐dioxa‐isotwistane (14), 2,7‐dioxa‐twistane (19), and some of their derivatives (6–13 and 15–18) are described.The twistane‐skeleton was obtained by a molecular rearrangement starting from the iodo‐iso‐twistane compound 8.
Über die Umlagerung von Benzo[b]‐1, 4‐thiazepinen und 1, 4‐Thiazepinen
Authors: Wilhelm Max , Schmidt Paul 
Published: December 2004

AbstractThe rearrangement of differently substituted 1, 4‐thiazepines under various reaction conditions has been investigated. 2‐Phenyl‐4‐methylthio‐benzo [b]‐1, 4‐thiazepine (3) and 2‐phenyl‐benzo [b]‐1, 4‐thiazepine‐4 (5H)‐thione (2) extrude sulfur under the catalytic influence of bases and rearrange into 2‐methylthio‐4‐phenyl‐quinoline (4) and 4‐phenyl‐thiocarbostyril (6) respectively. Under the same conditions, 2‐phenyl‐4‐methylthio‐2, 3‐dihydro‐benzo [b]‐1, 4‐thiazepine (11) rearranges to 2‐styryl‐benzothiazine (12), whereas the dioxide 18shows no tendency to rearrange. 2,7‐Diphenyl‐hexahydro‐1,4‐thiazepine‐5‐one(19) could be converted into 2‐styryl‐5‐phenyl‐2‐thiazoline (20) by treatment with polyphosphoric acid. The possible mechanisms of these rearrangements are discussed.
Die Bildung von L‐3‐Acylamino‐6,7‐dihydroxy‐hydrocumarinen aus N‐Acyl‐3‐(3,4‐dihydroxyphenyl)‐L‐alaninen
Authors: Kaiser A. , Koch W. , Scheer M. , Wölcke U. 
Published: December 2004

AbstractAus den N‐Acyl‐3‐(3,4‐dihydroxyphenyl)‐L‐alaninen 1a, 1b und 1c entstehen bei der Oxydation unter anderm die L‐3‐Acylamino‐6,7‐dihydroxy‐hydrocumarine 2a, 2b und 2c. Diese Reaktion stellt einen präparativ brauchbaren Weg zur Synthese von 3‐(2,4,5‐Tri‐hydroxyphenyl)‐L‐alanin (6‐Hydroxy‐L‐DOPA, 3) aus 3‐(3,4‐Dihydroxyphenyl)‐L‐alanin dar.
Valenzisomerisierung von cis‐Dienonen, II. 5‐Phenylpenta‐2, 4‐dienaldehyde [1]
Authors: Schiess P. , Seeger R. , Suter Chr. 
Published: December 2004

AbstractThe 5‐Phenylpenta‐2,4‐dienaldehydes 4, and 7, show an uncatalized cis‐trans‐isomerization of the 4,5‐double bond above 70 °C. The negative value of the activation entropy for these reactions points to the formation of the bicyclic valence isomeric 2H‐Pyrans 5 and 8 respectively in the rate determining step. Intermediate 5 can be trapped as its tetracyanoethylene cycloadduct 11.The cis‐trans isomeric 1,6‐diphenyl‐hexa‐1,3,5‐trienes 12a and 12b undergo above 150° a disrotatory ring closure to the bicyclic dienes 13 and 14 respectively.