bluuebunny/crossref_metadata_2025_split huggingface dataset:
A 13C‐NMR. Study of cis‐trans Isomeric Vitamins A, Carotenoids and Related Compounds
Authors: Englert Gerhard 
Published: December 2004

AbstractThe 1H‐decoupled 13C‐NMR. spectra of 35 all‐trans, 17 mono‐cis vitamin A compounds (acetates, alcohols, aldehydes, acids and esters) and of one 11, 13‐di‐cis compound (11, 13‐di‐cis retinol) are reported. Included in this investigation are desmethyl‐, desmethylethyl, and aryl‐vitamin A analogues and others as well as 30 reference compounds of smaller molecular weight. Furthermore, the 13C‐NMR. spectra of 23 β‐apo‐ and other carotenoids were studied. A complete assignment of the signals of all 106 compounds to the specific carbon atoms was achieved by extensive application of lanthanide shift reagents, mainly Yb(dpm)3, by CW‐offset and selective 1H‐decoupling experiments, by comparison of the shifts of related compounds, and in three cases by utilization of specifically deuteriated compounds (11, 12‐D2‐retinol and retinyl acetate, 15, 15′‐D2‐β‐carotene). The chemical shift differences between the cis‐ and trans‐vitamin A compounds and the applicability of the shift reagents for the assignment of the 13C‐NMR. spectra are discussed.
The Bond‐Rotational Mobility of Guanidinium Ion
Authors: Bally Thomas , Diehl Peter , Haselbach Edwin , Tracey Alan S. 
Published: December 2004

AbstractThe NMR. spectrum of guanidinium ion 1 is studied in anisotropic liquid crystalline nematic solution. Assuming an HNH‐angle of 120°, the distance ratio NH/NC = 0.784 is obtained, from which using NC = 1.330 Å (from X‐ray data) NH = 1.043 Å results. An upper bound for the free energy of activation for bond rotation of ΔG+ ≤ 13 kcal/mol is deduced. The bondrotational mobility of 1 is also investigated using the MINDO/3‐SCF‐procedure. The results obtained for the three conceivable consecutive activation energies for bond‐rotation indicate that the observed bond‐rotational mobility of 1 does not involve cooperative two‐ or three‐bond rotations. The ‘conjugative stabilization’ of 1 has been estimated to be of the order of 24–26 kcal/mol.
New β‐Lactam‐Antibiotics. Fluorinated Cephalosporins. Preliminary Communication. Modifikationen von Antibiotika. 15. Mitteilung
Authors: Müller Beat , Peter Heinrich , Schneider Peter , Bickel Hans 
Published: December 2004

AbstractNeue Cephalosporine, die in 3‐Stellung eine Fluormethylgruppe aufweisen (9, 17/Schema 1), wurden ausgehend von 2b unter Verwendung von 2‐Chlor‐1,1,2‐trifluor‐triäthylamin als Fluorierungsmittel hergestellt. Mit Piperidin‐schwefeltrifluorid erhielt man ferner aus 18 die 3‐Difluormethyl‐cephemverbindung 19 (Schema 2), die nach bekannten Methoden in antibakteriell wirksame Cephalosporine (20a, b) übergeführt wurde. 3‐Fluor‐cephemderivate, z.B. 23b, liessen sich ausgehend von entsprechenden 3‐Hydroxy‐cephemverbindungen, mit diesem Reagens jedoch nur in sehr geringer Ausbeute herstellen.
Eine stereospezifische, licht‐ und säurekatalysierte Allylumlagerung; Synthese von Paliclavin. 80. Mitteilung über Mutterkornalkaloide
Authors: Fehr Theo , Stadler Paul Albert 
Published: December 2004

A Stereospecific, Light‐ and Acid Catalyzed Allylic Rearrangement; Syntsesis of PaliclavineThe synthesis of paliclavine, a recently isolated metabolite of strain of Claviceps paspali STEVENS et HALL, was achieved by an acid‐ and photo‐sensitized stereoselective allylic rearrangement of chanoclavine‐I and isochanoclavine‐I. In a second approach N‐methyl‐chanoclavine‐I was converted to N‐methyl‐paliclavine by the same method, subsequent N‐demethylation led to paliclavine. The chemical prerequisites and the mechanism of the reaction are discussed.
Ringschlüsse an Chinonylmethanfarbstoffen und analogen Merocyaninen. 2. Mitteilung. Dihydronaphthophenazinone; Beeinflussung der Löslichkeitseigenschaften durch Substitution, Isolierung und Charakterisierung einer Zwischenstufe des Ringschlusses
Authors: Schelz Dieter , Priester Martin 
Published: December 2004

Cyclization Reactions of Quinonylmethane Dyes and Analogous Merocyanines. 2. Communication: Dihydro‐oxo‐naphto‐phenazines. Correlation of Solubility and Substitution. Isolation and Characterization of an Intermediate CompoundAn intermediate compound of the cyclization reaction of 2‐chloro‐3‐(1‐cyclohexyl‐3‐methyl‐1,2‐dihydroquinoxalin‐2‐ylidenmethyl)‐naphthoquinone was isolated and characterized by spectroscopic methods. 6‐Chloro‐8‐cyclohexyl‐5,8‐dihydronaphtho[1,2‐b]phenazinone was obtained as the final product of this reaction. Several more dihydronaphtho[1,2‐b]phenazinone dyes were synthesized. The relationship of substitution and solubility of the dyes is discussed. The visible and 1H‐NMR. and some mass spectra of the dyes are given.
Etude des cinétiques de décoloration thermique de spiropyrannes benzodithioliques‐1,3 photochromes. Comparaison avec leurs analogues benzothiazoliniques
Authors: Appriou Pierre , Guillerez Jean , Garnier Francis , Guglielmetti Robert 
Published: December 2004

AbstractNous avons étudié la transformation réversible de spiropyrannes benzodithioliques photochromes en mérocyanines: les spectres d'absorption de celles‐ci et leurs cinétiques de décoloration thermique sont suivis en utilisant un spectrophotomètre à enregistrement rapide couplé à un appareil de photolyse‐éclair. Les nombreuses inversions constatées par rapport aux résultats cinétiques obtenus en série benzothiazolinique pour des composés identiquement substitués, associées à des considérations sur les spectres visibles des photomérocyanines et à des effets de polarité de solvant, nous amènent à envisager pour les mérocyanines benzodithioliques une structure de type quinonique alors qu'en série benzothiazolinique une structure de type dipolaire a été mise en évidence.
Spectres photoélectroniques He(I) et He(II) du benzo[b]sélénophène et du benzo[b]tellurophène
Authors: Muller Jean‐François 
Published: December 2004

He(I) and He(II) photoelectron spectra of benzo[b]selenophene and benzo[b]telluropheneThe photoelectron spectra of benzo[b]selenophene (2) and benzo[b]tellurophene (1) have been recorded with He(I) and He(II) radiation and been compared to those of benzo[b]thiophene (3), benzo[b]furan (4), indole (5) and indene (6). The first four bands are correlated with π‐orbitals, of which the highest occupied one is strongly localized on the heteroatom in the case of 1. The results are in agreement with semi‐empirical PPP‐calculations.
Synthesis and Properties of 3,7‐Dehydrotropones
Authors: Szechner Barbara , Dreiding André S. 
Published: December 2004

Synthese und Eigenschaften von 3,7‐Dehydrotroponen7‐exo‐Brom‐7‐endo‐t‐butyl‐(9) und 7‐exo‐Chlor‐7‐endo‐phenyl‐bicyclo[3.2.0]hept‐2‐en‐6‐on(12) sowie 7,7‐Dichlor‐2,3‐benzo‐bicyclo[3.2.0]hept‐2‐en‐6‐on (16), das letztere hergestellt aus Dichlorketen und Inden (15), wurden mit 1 Moläquiv. N‐Bromsuccinimid behandelt. Die entsprechenden Hauptprodukte waren 4‐exo‐, 7‐exo‐Dibrom‐7‐endo‐t‐butyl‐(10) und 4‐exo‐Brom‐7‐exo‐chlor‐7‐endo‐phenyl‐bicyclo[3.2.0]hept‐2‐en‐6‐on (13) sowie 4‐exo‐Brom‐7, 7‐dichlor‐2, 3‐benzo‐bicyclo[3.2.0] hept2‐en‐6‐on (17). Neben dieser « normalen » Bromierung fand in zwei Fällen eine solche unter Allylisomerisierung statt: Als Nebenprodukt bei der Monobromierung von 12 wurde 4‐exo‐Brom‐6‐exo‐chlor‐6‐endo‐phenyl‐bicyclo[3.2.0]hept‐2‐en‐7‐on (14) gebildet und bei der Dibromierung von 9 (wahrscheinlich via 10) war das Hauptprodukt 2,4‐exo, 6‐exo‐Tribrom‐6‐endo‐t‐butyl‐bicyclo[3.2.0]hept‐2‐en‐7‐on (11).Aus der Behandlung der vier bromierten Bicycloheptenon‐Derivate 10, 11 und 13 sowie 17 mit 1,1 mol Triäthylamin bei tiefer Temperatur liessen sich 2‐t‐Butyl‐(5), 6‐Brom‐2‐t‐butyl‐(6) und 2‐Phenyl‐3, 7‐dehydrotropon(7) sowie 2‐Chlor‐4, 5‐benzo‐3, 7‐dehydro‐tropon (8) isolieren.Das Reaktionsverhalten und die spektralen Eigenschaften (1H‐NMR., 13C‐NMR., IR. und UV.) der Dehydrotropone 5, 6, 7 und 8, sowie ihr Zusammenhang mit deren Struktur werden detailliert beschrieben.
The Crystal and Molecular Structure of 12, 13‐Dibromopseurotin
Authors: Weber Hans Peter , Petcher Trevor J. , Bloch Peter , Tamm Christoph 
Published: December 2004

AbstractThe crystal structure of 12,13‐dibromopseurotin has been determined by single crystal X‐ray analysis. The crystals belong to space group P21 with a = 16.75, b = 9.63, c = 7.42 Å, β 95.9°, Z = 2. The structure was solved by the heavy atom technique and refined to R = 0.062 with 819 significant reflexions for 299 parameters.
Halogenierte Pyridine II. Reaktionen der 3‐Halogenmethyl‐pyridine
Authors: Horn Ulrich , Mutterer Francis , Weis Claus D. 
Published: December 2004

Halogenated pyridines II. Reactions of 3‐halogenomethyl‐pyridines.The facile syntheis of 3‐halogenomethyl‐pyridines provides an easy access to a variety of new 2, 6‐di‐ and 2, 5, 6‐trihalogented pyridines with various functional groups in the 3‐position of the pyridine ring. Substitution reactions of the 3‐halogenomethyl groups, their Friedel Crafts reactions, and nitrations of the halogenated pyridine ring are reported.
Halogenierte Pyridine IV. Kernchlorierte Pyridin‐3‐carbonsäuren
Authors: Mutterer Francis , Weis Claus D. 
Published: December 2004

Halogenated pyridines IV. Nuclear chlorinated pyridine‐3‐carboxylic acids.Chlorinated pyridine‐3‐carboxylic acids (nicotinic acids) are readily accessible by oxidation of nuclear chlorinated 3‐chloromethyl‐pyridines. The catalytic oxidation procedures proved to be by far the best ones of the methods tested.
15N Labelling: Potassium azide, tetrazoles and imidazoles
Authors: Wentrup Curt , Thétaz Célestin 
Published: December 2004

AbstractA simplified high‐yield preparation of end‐labelled potassium azide from K15NO3 is described. Treatment of 4‐chloropyrimidines with K15NN2 and subsequent gas‐phase pyrolysis gives ring‐labelled 1‐cyanoimidazoles in 80–100% yields. The cyano‐groups in the latter are easily removed by hydrolysis.
The Aldehyde Ketone Rearrangement. Rearrangement of Bis(4‐methoxyphenyl)‐acetaldehyde into 4,4′‐Dimethoxydeoxybenzoin
Authors: Tadros Wadie , Tadros Raouf Ramzi , Awad Sami Bassili 
Published: December 2004

AbstractThe formyl carbonyl group in bis(4‐methoxyphenyl)‐acetaldehyde does not contribute to the formation of the carbonyl group in 4,4′‐dimethoxydeoxybenzoin when the former rearranges to the latter by treatment with 50% (w/w) sulfuric acid.
Bemerkungen zur Synthese von 3‐Aminotoluol‐5‐sulfonsäure und 2‐Aminotoluol‐3‐sulfonsäure
Authors: Courtin Alfred 
Published: December 2004

Some comments on the synthesis of 3‐aminotoluene‐5‐sulfonic acid and 2‐aminotoluene‐3‐sulfonic acid.Sulfonation of 3‐nitrotoluene (5) yields predominantly the unsymetrical isomer 5‐nitrotoluene‐2‐sulfonic acid (7), and lesser amounts of 5‐nitrotoluene‐3‐sulfonic acid (6), previously reported as the major product. The desired 5‐aminotoluene‐3‐sulfonic acid (3) was synthesized in preparative amounts from 6‐aminotoluene‐3‐sulfonic acid (4) via the following sequence of reactions: diazotation and Sandmeyer replacement of 6‐chlorotoluene‐3‐sulfonic acid (13), nitration of the sulfonyl chloride 14 under suitable conditions to give isomer free 6‐chloro‐5‐nitrotoluene‐3‐sulfonyl chloride (15), hydrolysis to the sulfonic acid 16 and finally, simultaneous hydrogenolysis and reduction to 3. The isomeric 7 was unequivocally prepared from 2‐amino‐5‐nitrotoluene (9) via two routes: (1) diazotation, Sandmeyer thiocyanatation to 5‐nitro‐2‐thiocyanatotoluene (10), Na2S reduction to the di(2‐methyl‐4‐nitro‐phenyl)‐disulfide (11), treatment with nitric acid and chlorine to give 5‐nitrotoluene‐2‐sulfonyl chloride (12) and finally alkaline hydrolysis to 7; (2) Meerwein's SO2 treatment of the diazonium salt derived from 9 leads directly to 12 and thence to 7.2‐Aminotoluene‐3‐sulfonic acid (1) was prepared from the key intermediate 3‐amino‐2‐nitrotoluene (18) via the same two routes used to prepare 7 from 9. Both reaction sequences provided 2‐nitrotoluene‐3‐sulfonly chloride, the hydrolysis product of which was reduced to 1. Intermediate 18 was prepared in the following four steps from m‐toluic acid (19): nitration to the 2‐nitroderivative (20), whose acid chloride (21) was converted to 2‐nitro‐m‐toluamide (22), and Hoffmann rearrangement to 18.
Synthesis of Vitamin A via Sulfones: A C15 Sulfone Route
Authors: Manchand P. S. , Rosenberger M. , Saucy G. , Wehrli P. A. , Wong H. , Chambers L. , Ferro M. P. , Jackson W. 
Published: December 2004

AbstractA Synthesis of vitamin A has been achieved by alkylating a β‐ionylidene‐ethyl (C15) aromatic sulfone with 1‐acetoxy‐3‐chlormethyl‐2‐butene (C5) followed by elimination of the corresponding sulfinic acid.
Résonance Magnétique Nucléaire de 17O. Aldéhydes et cétones aliphatiques: additivité des effets de substitution et corrélation avec la 13C‐RMN
Authors: Delseth Claude , Kintzinger Jean‐Pierre 
Published: December 2004

17O‐NMR. Aliphatic aldehydes and ketones, additivity of substituent effects and correlation with 13C‐NMR.The 17O‐chemical shifts of 9 aldehydes, 22 aliphatic and 4 alicyclic ketones, in the natural abundance FT.‐NMR. spectra followed a good correlation with the 13C‐chemical shifts of the terminal C‐atoms of corresponding methylene compounds. An additivity relation involving 6 parameters represents the 17O‐shifts of 28 of the measured products with a standard deviation of 2.5 ppm. The additivity parameters are discussed with respect to the modifications of the polarity of the carbonyl group induced by the hyperconjugative interaction of π and π* orbitals with the πCH3 orbitals of the alkyl substituent groups.
The lead tetraacetate reaction of alcohols containing a small ring. Part II. Cyclobutane‐methanols and cyclopropane‐ethanols
Authors: Mihailović Mihailo Lj. , Bošnjak Jovan , Čeković Živorad 
Published: December 2004

AbstractThe leadtetraacetate and lead tetraacetate/metal chloride oxidations of cyclobutane‐methanol, cyclopropane‐ethanol and the corresponding α, α‐diniethyl alcohols have been investigated and compared with the oxidative reactions of cyclobutane‐carboxylic acid, cyclopropane‐acetic acid and 4‐pentenoic acid, performed with the same reagents and under similar conditions. It was found that alcohol β‐fragmentation and acid decarboxylation follow a remarkably similar mechanistic course, affording comparable results when the substrates are of the same structural type (1, 2 and 5; 3, 4 and 6) or are converted to the same intermediate alkyl radical fragments (3, 4, 6 and 7). In addition, cyclization products formed from cyclopropane‐ethanol (dihydropyran derivative 31) and 4‐penteuoic acid (γ‐lactones 38) have been isolated and identified.
Reactions with the Arylhydrazones of α‐Cyanoketones: The Structure of 2‐Arylhydrazono‐3‐ketimino‐nitriles
Authors: Elnagdi Mohamed Hilmy , Sallam Mohamed Mohamed Mohamed , Fahmy Hussein Mahmoud , Ibrahim Saad Abdel‐Motteleb , Elias Mohamed Ajmal Mohamed 
Published: December 2004

AbstractAnalysis of the IR., UV., and polarographic data of a variety of 2‐arylhydrazono‐3‐ketimino‐nitriles indicated that these derivatives exist mainly in the intramolecularly chelated hydrazone structure 1.Compounds 1 reacted with hydrazine hydrate to yield the corresponding 5‐amino‐4‐arylazopyrazoles (3).Compounds 3a reacted with acetylacetone, ethyl acetoacetate, and diethyl malonate to yield the pyrazolo[1, 5‐a]pyrimidine derivatives 4, 5, and 7 respectively. Compound 3a also reacted with benzoylisothiocyanate to yield the pyrazolyl thiourea derivative 8.
The Crystal Structure of the NH4NCS Complex of Nonactin
Authors: Neupert‐Laves Katarina , Dobler Max 
Published: December 2004

AbstractThe NH4NCS complex of the macrotetrolide antibiotic nonactin crystallizes in the space group P1, a = 12.565, b = 13.115, c = 14.999 Å, α= 91.22, β= 90.10, γ= 104.97°. The X‐ray crystal structure analysis shows that the NH ion is coordinated by hydrogen bonds to the four ether oxygen atoms (NH … O, 2.86 Å). These four atoms and the four carbonyl oxygen atoms (N … O, 3.08 Å) enclose the NH ion in a somewhat distorted cube.
Herstellung von Dihydro‐, Tetrahydro‐ und Hexahydrochelidamsäure‐Derivaten
Authors: Hermann Kurt , Dreiding André S. 
Published: December 2004

Preparation of dihydro‐, tetrahydro‐ and hexahydro‐chelidamic‐acid derivatives.Three methods for the preparation of 4‐oxo‐2,6‐piperidine‐dicarboxylic acid (3) and derivatives, required as a synthon for betalaine pigments, were explored.The best method was found to be the catalytic hydrogenation of chclidamic acid (1) with 5% Rh/Alox in water under 2.7 atm. H2 for 33 h at 70° and subsequent esterification with methanol which gave 42% of cis, cis‐4‐hydroxy‐2,6‐piperidine‐ (7) and 10% of 2,6‐cis‐piperidine‐dicarboxylic acid dimethyl ester (8), readily separable by chromatography. Oxidation of 7 with dimethylsulfoxide and a carbodiimide attached to a polymer afforded 90% of 4‐oxo‐2,6‐cis‐piperidine‐dicarboxylic acid dimethyl ester (19). Other methods of oxydizing 7 to 19 were less successful.The electrochemical reduction of 1 followed by esterification with methanol led in a low yield to a mixture of 4‐oxo‐0‐2,6‐trans‐piperidine‐dicarboxylic acid dimethylester (24), its dimethyl acetal 25 and presumably trans‐4‐hydroxy‐r‐2, cis‐6‐piperidine‐dicarboxylic acid dimethyl ester (26).Reaction of 4‐oxo‐hepta‐2E, 5E‐dienoic acid (35) with aqueous ammonia gave a 98% yield of a 3 : 2 mixture of cis‐ and trans‐ammonium‐4‐oxo‐2, 6‐piperidine‐dicarboxylate (39 and 40).The above mentioned catalytic hydrogenation method was also applied to N‐ethyl‐chelidamic acid (16) to give a 4:6 mixture of the N‐ethyl derivatives 17 and 18. Furthermore, a number of functional derivatives of 5, of 19, of 39 and of 40 were prepared.Oxidation of the hydroxy‐diester 7 with dimethylsulfoxide and a carbodiimidc derivative in the presence of trifluoroacetic acid afforded 4‐oxo‐1,2,3,4‐tetrahydro‐2, 6‐pyridine‐dicarboxylic acid dimethyl ester (50). This ester was also obtained under the same conditions from thc keto‐diester 19.
Ringschlüsse an Chinonylmethanfarbstoffen und analogen Merocyaninen. 4. Mitteilung. Dihydro‐anthracenophenazinone
Authors: Schelz Dieter , Priester Martin 
Published: December 2004

Dihydro‐anthracenophenazinones (Cyclization of Quinonylmethane Dyes), 4th Communication.Substituted dihydroanthraceno[1,2‐b]phenazinones were synthetized by reaction of 1‐alkyl‐2,3‐dimethyl‐quinoxalinium‐perchlorates with dichloro‐ or tetrachloro‐1,4‐anthraquinone and cyclization of the intermediate quinoxalylidenmethyl‐1, 4‐anthraquinones. The tetrachloro derivative of 1,4‐anthraquinone obtained by chlorination in boiling acetic acid in the presence of iodine is identified to be the 2,3,6,9‐isomer. The properties of the dihydroanthraceno[1,2‐b]phenazinones are discussed. The visible, mass, and some 1H‐NMR. spectra are given.
Ringschlüsse an Chinonylmethanfarbstoffen und analogen Merocyaninen. 5. Mitteilung. Ein Ringschluss am substituierten Indandion
Authors: Schelz Dieter , Priester Martin 
Published: December 2004

Cyclization of a substituted Indandion (Cyclization of Quinonylmethane Dyes, 5th Communication).An unexpected product was obtained from the reaction of 2‐[1‐ethoxyethylidene]indan‐1,3‐dione and 1‐ethyl‐3‐methyl‐2‐methylidene‐1,2‐dihydroquinoxaline. The visible, 1H‐NMR., and mass spectra of the product are given.
Synthese des (R)‐trans‐11‐Hydroxy‐8‐dodecensäure‐lactons (Recieifeiolid)
Authors: Gerlach Hans , Oertle Konrad , Thalmann Adolf 
Published: December 2004

Synthesis of RecifeiolideThe synthesis of the mould metabolite recifeiolide (VIII), a 12‐membered ring lactone, is described. 1,3‐Butandiol was resolved with (−)‐camphanic acid via (R)‐1‐iodo‐3‐butanol (II) into (R)‐3‐hydroxybutyl triphenyl phosphonium iodide (III). Wittig condensation of the phosphorane derived from III with methyl 8‐oxo‐octanoate (V) led to the methyl trans‐11‐hydroxy‐8‐dodecenoate (VI). The corresponding hydroxy acid VII was transformed into the S‐(2‐pyridyl) carbothioate which cyclizes under the influence of silver ion to the lactone VIII. With (−)‐(R)‐1,3‐butandiol (I) as starting material the naturally occurring (+)‐(R)‐recifeiolide (VIII) is produced in 70% yield from VII.
Synthesis of 3,7‐Diacetoxy‐benzo‐bullvalene
Authors: Chapleo Christopher B. , Dreiding André S. 
Published: December 2004

AbstractDurch partielle reduktive Fragmentierung von 9,9a‐Benzo‐9a‐homotriaster‐9‐en‐3,7‐dion (6) mit Zinkstaub in Eisessig wurde 61% 9,10‐Benzo‐tricyclo[3.3.2.02,8]‐dec‐9‐en‐3,7‐dion (3) und daraus mit Isopropenyl‐acetat 47% 3,7‐Diacetoxy‐benzo‐bullvalen (4) erhalten. Eine relativ schnelle degenerierte Cope‐Umlagerung in 4 liess sich durch die Temperaturabhängigkeit von dessen 1H‐NMR.‐Spektrum aufzeigen. Mildere Acetylierung von 3 lieferte das Mono‐enolacetat 9.Unter etwas energischeren Bedingungen der Zink/Eisessig‐Reduktion wurden beide Cyclopropanringe in 6 aufgespalten, wobei 90% eines Gemisches, hauptsächlich bestehend aus 9,10‐benzo‐bicyclo[3.3.2]dec‐9‐en‐3,7‐diol (7) entstand. Behandlung von 6 mit Zinkstaub in Acetanhydrid lieferte – offenbar wegen noch unübersichtlichen Unterschieden in den Reaktionsbedingungen – einmal 50% des oben erwähnten tricyclischen Diketons 3, ein andermal 45% 3,8‐Diacetoxy‐9,10‐benzo‐bicyclo[3.3.2]deca‐2,9‐dien‐7‐on (10) und sonst Gemische von 3 und 10, sowie von einem Produkt, für das die Struktur eines 3,7‐Diacetoxy‐9,10‐benzo‐tricyclo[3.3.2.02,8]dec‐9‐en – Diastereomerengemisches 11 in Betracht gezogen wird.
Preparation of 1,2,3‐ Triarylpropane compounds
Authors: Coviello Vincenzo , Siegrist Adolf Emil 
Published: December 2004

AbstractAnile aromatischer Aldehyde können mit 2 Mol‐Äquiv. 2,5‐Dichlortoluol oder mit 2 Mol‐Äquiv. in 2‐Stellung durch 3‐Chlor‐4‐methyl‐phenyl substituierte 2H‐Benzotriazole, 2H‐Naphtho[1,2‐d]triazole, Oxazole oder Benzoxazole in Gegenwart von Dimethylformamid und Kaliumhydroxid in die entsprechenden 1,2,3‐Triarylpropan‐Derivate übergeführt werden. Der Chlorsubstituent in o‐Stellung zur Methylgruppe bestimmt wesentlich gute Ausbeuten und einen leichten Reaktionsverlauf, welcher weiterhin durch Abwesenheit von Licht begünstigt, in vielen Fällen erst ermöglicht wird.
Über das fluktuierende Verhalten von triphenylmethylsubstituierten Cyclopentadienyl‐Metallverbindungen
Authors: Kläui Wolfgang , Werner Helmut 
Published: December 2004

The fluxional behaviour of triphenylmethyl substituted cyclopentadienyl metal compounds1H‐NMR. spectroscopy has been used to study the influence of the triphenylmethyl substituent on the metallotropic rearrangement in C5H4(CPh3)Si(CH3)3 and C5H4 (CPh3)Sn(CH3)3. The most likely mechanism corresponds to a degenerate metal exchange between two neighbouring ring positions. The AA'XX' spectrum of the cyclopentadienyl ring protons in C5H4(CPh3)Sn(CH3)3 has been analysed under rapid exchange conditions. The free energy of activation for the sigmatropic [1,5]‐Sn shift has been measured by comparison with computer simulated spectra for slow exchange.
Dérivés C‐Glycosyliques XXXI. Utilisation en chimie des sucres du synthon bromo‐2‐cyano‐2‐éthényle. Communication préliminaire
Authors: Tronchet Jean M. J. , Martin Olivier R. 
Published: December 2004

C‐Glycosyl derivatives XXXI. Some uses in Carbohydrate Chemistry of the 2‐bromo‐2‐cyano ethenyl synthonSugars bearing the synthon 2‐bromo‐2‐cyano‐ethenyl, CαHCγ(Br)CN, reacted with binucleophiles, gave rise to α, α, α, β or α, γ ring‐forming reactions. C‐glycosyl‐dioxolanes, ‐aziridines, ‐dithianes, ‐pyrimidines, ‐furanes and ‐pyrazoles were so obtained. The stereochemical paths of some of these reactions are discussed.