bluuebunny/crossref_metadata_2025_split huggingface dataset:
Der Stoffwechsel von Verbindungen mit Dreifachbindung. VI. Stoffwechselverhalten von Alkincarbonsäuren und Alkindicarbonsäuren
Authors: Graf Peter , Kaempf Ekkehard , Reichlmeier Klaus , Bernhard Karl 
Published: December 2004

Metabolism of Acetylenic Monocarboxylic and Dicarboxylic AcidsFeeding of acetylenic monoacids with chain length of 11 to 18 C‐atoms to rats led to excretion of dicarboxylic acids with retained triple bonds. 10‐Octadecynoic acid led to the formation of metabolites with even and odd number of C‐atoms, suggesting in addition to established ω‐ and β‐oxidation an α‐oxidative pathway.
Sesquiterpenoids from Costus Root Oil (Saussurea lappa CLARKE)
Authors: Maurer Bruno , Grieder Alfred 
Published: December 2004

AbstractApart from the well‐known constituents (+)‐β‐selinene (2), (−)‐β‐elemene (4), (+)‐β‐costol (7), (−)‐caryophyllene (17), and (−)‐elemol (19) the following sesquiterpenoids have been isolated for the first time from costus root oil (Saussurea lappa CLARKE): (−)‐α‐selinene (1), (+)‐selina‐4, 11‐diene (3), (−)‐α‐trans‐bergamotene (5), (−)‐α‐costol (6), (+)‐γ‐costol (8), (−)‐elema‐1,3,11 (13)‐trien‐12‐ol (9), (−)‐α‐costal (11), (+)‐γ‐costal (12), (+)‐γ‐costal (13), (−)‐elema‐1,3,11 (13)‐trien‐12‐al (elemenal, 14), (−)‐(E)‐trans‐bergamota‐2, 12‐dien‐14‐al (15), (−)‐ar‐curcumene (16), and (−)‐caryophyllene oxide (18). Compounds 6, 8, 9, and 13 are new sesquiterpenoids. IR. and NMR. spectra of 12 sesquiterpenoids are reproduced.
Die Bromierung von «Push‐Pull»‐Olefinen. II. Die Struktur der Bromierungsprodukte
Authors: Bürgi Daniel , Sterchi Alfred , Neuenschwander Markus 
Published: December 2004

The Bromination of Push‐Pull‐Olefins. II. Structure Elucidation of the Bromination ProductsBromination of 3‐dialkylamino‐acroleins 1a, b as well as of 4‐dialkylamino‐3‐buten‐2‐ons 1c, d gives O‐protonated produkts 2 with all‐trans configuration of the (NCCCO)‐skeleton. The structure of these hydrobromides 2 is confirmed by 1H‐ as well as by 13C‐NMR. evidence.
Base Catalysed Racemization of Ethylenediamine‐N,N,N′‐triacetato‐aqua‐cobalt(III)
Authors: Bernhard C. A. , Bernauer K. 
Published: December 2004

AbstractThe kinetics of the base catalysed racemization of [Co(EN3A)H2O]Abbreviations: EN3A3−=(−OOCCH2)2N(CH2)2NHCH2COO−; ME3A3−=(−OOCCH2)2N(CH2)2 N(CH3)CH2COO−; EDDA2−=−OOCCH2NH(CH2)2NHCH2COO−; EDTA4−=(−OOCCH2)2N(CH2)2N(CH2COO−)2;TNTA4−=(−OOCCH2)2N(CH2)3N(CH3COO−)2; HETA3−=(−OOCCH2)2N(CH2)2N(CH2COO−)CH2CH2OH; en=H2N(CH2)2NH2; Meen=H2N(CH2)2NHCH3; sar−=−OOCCH2NHCH3.
were studied polarimetrically in aqueous buffer solution. The reaction rate is first order in OH− and in complex, in weakly acidic medium. Activation parameters are ΔH≠=22 kcal · mol−1, ΔS≠=26 cal · K−1. The results are discussed in terms of an SN1CB mechanism involving exchange of the ligand water molecule.The N‐methylated analogue [Co(ME3A)H2O] does not racemize in the pH‐range investigated. Loss of optical activity occurs at a rate which is about 1,000 times slower than the racemization of [Co(EN3A)H2O](60°) and coincides with the decomposition of the complex.
Notiz über den Austausch einer Cyanogruppe durch eine Dialkylaminogruppe in Cyclobuten‐1,2‐dicarbonitril und (E)‐Äthylendinitril
Authors: Belluŝ Daniel 
Published: December 2004

A Note on Exchange of a Cyanogroup for a Dialkylaminogroup in Cyclobutene‐1,2‐dicarbonitrile and (E)‐EthylenedinitrileReactions of electrophilic cyclobutene‐1,2‐dicarbonitrile and (E)‐ethylene‐dinitrile with secondary amines lead to 1:1 adducts of type 3 and 12, respectively. These adducts eliminate hydrocyanic acid either thermally or, more conveniently for preparative purposes, upon treatment with a strong base (e.g. t‐butoxide or methoxide) affording 2‐dialkylaminocyclobutenes‐1‐carbonitriles 4 and 3‐dialkylamino‐acrylnitriles 13, resp., in high yields.
Die massenspektrometrische Retro‐Diels‐Alder‐Reaktion: 1,2,3,4‐Tetrahydrocarbazol. 30. Mitteilung über massenspektrometrische Untersuchungen
Authors: Neukomm Gisela , Hesse Manfred 
Published: December 2004

The mass spectral retroDiels‐Alder‐reaction: 1,2,3,4‐tetrahydrocarbazole1,2,3,4‐Tetrahydrocarbazole undergoes a retroDiels‐Alder‐reaction under electron impact. C(2) and C(3) are eliminated as ethylene. This is shown by measuring the deuterated derivatives1a,1band1c. Furthermore the oxo‐1,2,3,4‐tetrahydrocarbazole derivatives3and4are investigated in respect to the mass spectral retroDiels‐Alderreaction too.
Synthese und Reaktionen 8‐gliedriger Heterocyclen aus 3‐Dimethylamino‐2,2‐dimethyl‐2H‐azirin und Saccharin bzw. Phthalimid
Authors: Chaloupka Stanislav , Vittorelli Piero , Heimgartner Heinz , Schmid Hans , Link Helmut , Bernauer Karl , Oberhänsli Willi E. 
Published: December 2004

Synthesis and Reactions of 8‐membered Heterocycles from 3‐Dimethylamino‐2,2‐dimethyl‐2H‐azirine and Saccharin or Phthalimide3‐Dimethylamino‐2,2‐dimethyl‐2H‐azirine (1) reacts at 0‐20° with the NH‐acidic compounds saccharin (2) and phthalimide (8) to give the 8‐membered heterocycles 3‐dimethylamino‐4,4‐dimethyl‐5,6‐dihydro‐4 H‐1,2,5‐benzothiadiazocin‐6‐one‐1,1‐dioxide (3a) and 4‐dimethylamino‐3,3‐dimethyl‐1,2,3,6‐tetrahydro‐2,5‐benzodiazocin‐1,6‐dione (9), respectively. The structure of 3a has been established by X‐ray (chap. 2). A possible mechanism for the formation of 3a and 9 is given in Schemes 1 and 4.Reduction of 3a with sodium borohydride yields the 2‐sulfamoylbenzamide derivative 4 (Scheme 2); in methanolic solution 3a undergoes a rearrangement to give the methyl 2‐sulfamoyl‐benzoate 5. The mechanism for this reaction as suggested in Scheme 2 involves a ring contraction/ring opening sequence. Again a ring contraction is postulated to explain the formation of the 4H‐imidazole derivative 7 during thermolysis of 3a at 180° (Scheme 3).The 2,5‐benzodiazocine derivative 9 rearranges in alcoholic solvents to 2‐(5′‐dimethylamino‐4′,4′‐dimethyl‐4′H‐imidazol‐2′‐yl) benzoates (10, 11), in water to the corresponding benzoic acid 12, and in alcoholic solutions containing dimethylamine or pyrrolidine to the benzamides 13 and 14, respectively (Scheme 5). The reaction with amines takes place only in very polar solvents like alcohols or formamide, but not in acetonitrile. Possible mechanisms of these rearrangements are given in Scheme 5.Sodium borohydride reduction of 9 in 2‐propanol yields 2‐(5′‐dimethylamino‐4′,4′‐dimethyl‐4′H‐imidazol‐2′‐yl)benzyl alcohol (15, Scheme 6) which is easily converted to the O‐acetate 16. Hydrolysis of 15 with 3N HCl at 50° leads to an imidazolinone derivative 17a or 17b, whereas hydrolysis with 1N NaOH yields a mixture of phthalide (18) and 2‐hydroxymethyl‐benzoic acid (19, Scheme 6). The zwitterionic compound 20 (Scheme 7) results from the hydrolysis of the phthalimide‐adduct 9 or the esters 11 and 12. Interestingly, compound 9 is thermally converted to the amide 13 and N‐(1′‐carbamoyl‐1′‐methylethyl)phthalimide (21, Scheme 7) whose structure has been established by an independent synthesis starting with phthalic anhydride and 2‐amino‐isobutyric acid. However, the reaction mechanism is not clear at this stage.
Aromatic Radical Anions with Parallel or Crossed Triple Bonds
Authors: Elschenbroich Christoph , Gerson Fabian , Ohya‐Nishiguchi Hiroaki , Wydler Christoph , Nissen Axel 
Published: December 2004

AbstractProton hyperfine data are reported for the radical anions of 1,8‐di (propyn‐1‐yl)‐naphthalene (I), 7,8,12,13‐tetradehydro‐10,11‐dihydro‐9H‐cyclodeca[d,e]naphthalene (II) and 2,2′‐di(propyn‐1‐yl)‐biphenyl (III), as well as of 5,6,11,12‐tetradehydro‐7,8,9,10‐tetrahydro‐dibenzo[a,c]cyclodecene (IV) and its 8,8,9,9‐tetradeuterio‐derivative (IV‐d4). The triple bonds in I and II can be regarded as roughly parallel, while those in IV (and IV‐d4) may be considered as crossed. The π‐spin distributions in I⊖ to IV⊖ are discussed in terms of simple MO models which suggest a weekly bonding interaction between the acetylenic fragments in IV⊖, in contrast to III⊖ where such an effect appears to be negligible. The importance of an analogous interaction in I⊖ and II⊖ is difficult to deduce, since its inclusion into a MO model does not substantially affect the π‐spin distribution in these radical anions.
Minor Lankamycin‐Related Antibiotics from Streptomyces violaceoniger
Authors: Martin Jerry R. , Egan Richard S. , Goldstein Alma W. , Stanaszek Ruth S. , Tadanier Jack , Keller‐Schierlein Walter 
Published: December 2004

AbstractSeveral previously undescribed metabolites related to lankamycin have been isolated from fermentation broths of the lankamycin‐producing organism Streptomyces violaceoniger. Two of these metabolites, of weak antibacterical activity, have been characterized as 15‐O‐(α‐L‐4‐O‐acetyl‐arcanosyl)‐lankamycin and 15‐deoxy‐15‐oxo‐lankamycin. The latter antibiotic is prepared in high yield by Jones oxidation of lankamycin.
Electron Transfer in Monolayer Assemblies with Incorporated Ruthenium (II) Complexes
Authors: Seefeld Karl‐Peter , Möbius Dietmar , Kuhn Hans 
Published: December 2004

AbstractAn arrangement for light induced vectorial charge separation is discussed in which the electron of the excited dye is transferred to an acceptor and the dye is recovered by electron tunneling through a high and narrow potential barrier. The possible relevance of the model in connection with photosynthesis is considered. Monolayers of Ru(II)‐bipyridine complexes with long chain hydrocarbon substituents were investigated which may be useful as component in such arrangements.The surface pressure area isotherms of the monolayers were measured for various ionic compositions of the subphase, and the results demonstrate a strong effect of these ions on the structure of the layers. The layers were deposited on different substrates. The luminescence and its change by contacting the sample with water and by subsequent drying were found to be strongly dependent on the architecture of the layer assembly. Attempts of a photochemical cleavage of water with these assemblies failed.The pH‐dependence of the absorption and the luminescence of a Ru(II) bipyridine‐dicarboxylic acid complex in solution is interpreted by assuming that the electron in the excited state is localized in one pyridine part of the substituted ligand, the conjugation with the second half of the bipyridine carboxylic acid being negligible. Monolayer assemblies for measuring the energy transfer from the ruthenium complex to an adequate energy acceptor and from an adequate energy donor to the ruthenium complex were investigated. The results demonstrate that the deactivation of the excited ruthenium complex occurs mainly by passing the luminescent state.Assemblies were investigated for measuring the electron transfer from the excited ruthenium complex to an appropriate electron acceptor positioned in the carboxylate portion at the same interface as the electron donor. With bipyridinium ions as acceptor the ruthenium complex luminescence is quenched at average distances between acceptor molecules of about 10 Å, while this distance is 30, 60 und 75 Å for different cyanine dyes used instead of the ruthenium complex. A correlation between this distance and the ionization energy in the excited state of the donor is observed.
Stabilité en solution aqueuse de complexes de métaux lourds avec des ligands diaza‐polyoxamacrocycliques
Authors: Arnaud‐Neu Françoise , Spiess Bernard , Schwing‐Weill Marie‐José 
Published: December 2004

Stability in aqueous solution of some complexes of heavy metals with diaza‐polyoxamacrocyclic ligandsStability of metal complexes (Mn+ = Cu2+, Ni2+, Co2+, Zn2+, Pb2+, Ag+ and Cd2+) with five diaza‐polyoxamacrocycles (L = [2.1.1], [2.2.1], [2.2.2], [2.1] and [2.2] ) have been determined at 25°, in 0.1 M Et4N+ClO aqueous solutions, by means of potentiometric titrations. All cations form MLn+ complexes; Cu2+ also forms the MHL(n+1)+ protonated species with both [2.2.1] and [2.1.1] ligands. The stability of these complexes has been discussed in terms of structure and by considering the ionic radii of the cations together with the radii of the macrocyclic cavities. Different behaviour is observed between some of these complexes and the well known alkali and alkaline‐earth cryptates, partly due to the more covalent nature of bonds formed by the investigated cations and the donor sites of the ligands. The effect of the substitution of two oxygen by two sulfur atoms in the pentadentate ligand [2.1] on the stability of the complexes is reported.
The Reaction of Biadamantylidene with Singlet Oxygen in the Presence of Dyes [1]
Authors: Jefford Charles W. , Boschung André F. 
Published: December 2004

AbstractSinglet oxygen, generated chemically or photogenetically, reacts with biadamantylidene to give the corresponding dioxetane and epoxide only. When methylene blue (MB) or meso‐tetraphenylporphin (m‐TPP) is used as sensitizer the normal reaction course occurs giving dioxetane as the preponderant product in 2‐propanol, ethyl acetate, acetone, pinacolone, methylene chloride, chloroform, carbon tetrachloride and benzene, although in the last two solvents some 10–25% of epoxide is formed. When erythrosin and rose bengal (RB) are used, epoxide becomes the main product (70–95%). Epoxide does not derive from chemical reaction with the solvent. Pinacolone, for example, is not oxidized to t‐butyl acetate.The rose bengal reaction involves both singlet oxygen and radicals, since diazabicyclooctane (DABCO) and di‐t‐butyl‐p‐cresol interfere with the oxidation. A mechanistic scheme is proposed in which sensitizer and oxygen combine to produce sensitizer radical cation and superoxide radical anion. Subsequently, hydroperoxy radical, deriving from superoxide, reacts with substrate to give epoxide and hydroxy radicals. The latter adds to substrate to give a new radical which captures triplet oxygen. Epoxide is formed by loss of hydroperoxy radical and the chain starts anew. The dioxetane is formed separately either by [2+2]‐cycloaddition or stepwise addition.
Tetracarbonyleisenkomplexe von trans‐Cycloalkenen und trans‐Cycloalkadienen. Vorläufige Mitteilung
Authors: von Büren Martin , Hansen Hans‐Jürgen 
Published: December 2004

Tetracarbonyliron Complexes of trans‐Cycloalkenes and trans‐CycloalkadienesRelatively stable olefin tetracarbonyliron complexes were obtained by reaction of Fe2(CO)9 with trans‐cyclooctene (t‐1), trans‐cyclononene (t‐2) and trans‐cyclodecene (t‐3) (Scheme 2) in pentane solution at room temperature. Furthermore, trans,cis‐cycloocta‐1,5‐ and ‐1,3‐diene (t,c‐7 and t,c‐8) as well as trans,trans,cis‐2,8,12‐trans‐bicyclo[8.4.0]tetradecatriene (t,t,c‐9) gave stable complexes only with the trans‐configurated double bond (Scheme 3).An olefin tetracarbonyliron complex was also obtained with bicyclo[4.3.1]deca‐7,9‐diene (10) which reacted only at the strained bridge‐head double bond. The IR. spectra of the new complexes are in agreement with an equatorial position of the olefinic ligands in the trigonal bipyramide of the iron.
Stereochemical Structure of the Dihydrothiazines. I. 1H‐NMR. Determination of the Stereochemistry of two Reduction Products of Benzo[b]‐5α‐17β‐hydroxy‐androst‐2‐eno [2,3‐e][1,4]thiazine
Authors: Sciacovelli Oronzo , Marchini Paolo , Liso Gaetano , Reho Antonia 
Published: December 2004

AbstractThe stereochemical structure of two reduction products of benzo[b]‐5α‐17β‐hydroxy‐androst‐2‐eno[2,3‐e] [1,4]thiazine has been determined by 1H‐NMR. Spectrometry using the INDOR technique.
Permanganate Oxidation of Ambrein and the Absolute Configuration of Dihydro‐γ‐ionone (Supplement and Rectification)
Authors: Ohloff Günther , Vial Christian 
Published: December 2004

AbstractCompounds 2 to 7 were identified among the products obtained from ambrein (1) by potassium permanganate oxidation; (+)‐dihydro‐γ‐ionone (3) was shown to have the S‐configuration.
Diterpenoide Drüsenfarbstoffe aus Labiaten: 3β‐Acetoxyfuerstion, Nilgherron A und Nilgherron B, neue Chinomethane aus Plectranthus nilgherricus BENTH.; absolute Konfiguration von Fuerstion
Authors: Miyase Toshio , Rüedi Peter , Eugster Conrad Hans 
Published: December 2004

Leaf‐gland Pigments: 3β‐Acetoxyfuerstione, Nilgherron A and Nilgherron B, New Quinomethanes from Plectranthus nilgherricus BENTH. (Labiatae); Absolute Configuration of FuerstioneWe have isolated from leaf‐glands of the above mentioned plant the following deeply coloured quino‐methane derivatives: (1) traces of the already known fuerstione (1a); 11,15‐dihydroxy‐5,7,9 (11), 13‐abietatetraen‐12‐one; (2) the new 3β‐acetoxy‐fuerstione (1b); (3) nilgherron A (5a, I or II), a new dimeric diterpenoid quinomethane, C40H52O7, formed in the plant obviously by cycloaddition of the o‐quinone 8 (9aS, 11R)‐11 ‐hydroxy‐2‐(1‐hydroxy‐1‐methylethyl‐9,9‐dimethyl‐3,4,7,8,9,9a,10,11‐ octahydro‐5H‐dibenzo [a, d]cycloheptene‐3,4‐dione) with fuerstione; (4) nilgherron B (5b, I or II), C42H54O9, likewise a new compound, formed by the same type of cycloaddition (heterodiene synthesis) of 8 with 3β‐acetoxyfuerstione. On the basis of 1H‐NMR. shift arguments structure I is slightly preferred to II for 5a and 5b. Model experiments have shown the easy formation of the dihydrodioxin ring by reaction of an o‐benzoquinone with p‐quinomethanes. The absolute configuration of fuerstione and 3β‐acetoxyfuerstione has been determined by chiroptical methods.
Transition metal complexes with bidentate ligands spanning trans‐positions. VI. The preparation of some diaryl‐ and dialkyl derivatives of 2,11‐bis (phosphinomethyl)benzo [c]phenanthrene
Authors: Kapoor Pramesh N. , Venanzi Luigi M. 
Published: December 2004

AbstractThe preparation of the ditertiary phosphines 2,11‐bis (di‐m‐tolylphosphinomethyl)benzo [c]phenanthrene (1b), 2,11‐bis (di‐p‐anisylphosphinomethyl)benzo‐[c]phenanthrene (1c), 2,11‐bis (di‐m‐trifluoromethylphenylphosphinomethyl) benzo‐[c]phenanthrene (1d), 2,11‐bis (dicyclohexylphosphinomethyl)benzo [c]phenanthrene (1e) and 2,11‐bis [di‐(t‐butyl)phosphinomethyl]benzo [c]phenanthrene (1f), by a combination of synthetic routes is described.
Die Struktur des Bisindolalkaloides Amatain ( = Grandifolin, Subsessilin)
Authors: Agwada Vincent C. , Naranjo Jorge , Hesse Manfred , Schmid Hans , Rolland Yves , Kunesch Nicole , Poisson Jacques , Chatterjee Asima 
Published: December 2004

The structure of the bisindole alkaloid amataine (= grandifoline, subsessiline)Amataine (1) was isolated from the roots of Hedranthera barteri (HOOK. F.) PICHON (Apocynaceae). In comparison to the alkaloid vobtusine (5), which was isolated from the same plant, 1 contains two hydrogen atoms less. By reduction of 1 with H2/PtO2 or with NaBH4 dihydromataine ( = isovobtusine, 13) was formed which is isomeric to 5. Acid catalysed water addition to 1 afforded hydratoamataine (15), which was reduced to 5 with NaBH4. Thermolysis of 15 gave 1. The difference between the two isomeric bases 5 and 13 has to be attributed to a different configuration at the spirocenter C(7). In contrast to 5 amataine (1) contains an ether bridge instead of a hydroxy group; this bridge is located between C (2′) and C (8).
Eine neue Synthese von (±)‐Pyrenophorin
Authors: Gerlach Hans , Oertle Konrad , Thalmann Adolf 
Published: December 2004

A new Synthesis of (±)‐PyrenophorinThe synthesis of pyrenophorin (I), a 16‐membered dilactone metabolite of plant pathogenic fungi is described. Reaction of the Grignard reagent II with the activated succinic acid ester III gave the methyl (t‐butyl)dimethylsilyloxy‐oxo‐octanoate IV which was converted into the corresponding ethylene acetal. Dehydrogenation via the benzeneselenenyl derivative lead to pyrenophorinic acid V with protected functional groups. Selective removal of silyl group followed by saponification of the ester group provided the ethylene acetal‐hydroxy acid VI suitable for the cyclodimerisation reaction. This was effected with azodicarbonic acid ester and triphenylphosphine at −40° in a dilute toluene solution. The 16‐membered dilactones VII with protected carbonyl groups were isolated in 24% yield. Silver‐ion induced cyclodimerisation of the S‐2‐pyridyl carbothioate of VI gave much lower yields. Removal of the acetal groups lead to (±)‐pyrenophorin (I) and meso‐pyrenophorin in about equal amounts.
Synthese des (±)‐Lasiodiplodins
Authors: Gerlach Hans , Thalmann Adolf 
Published: December 2004

Synthesis of (±)‐LasiodiplodinThe synthesis of the plant growth inhibitor (±)‐lasiodiplodin (VII), a 12 membered lactone of a substituted resorcylic acid is described. Condensation of methyl acetoacetate and methyl 11‐hydroxy‐2‐undecenoate followed by treatment of the product with benzyl alcohol lead to the benzyl ether II which was aromatized via the benzeneselenenyl derivative. Methylation of the phenolic hydroxyl in III and conversion of the primary alcohol in the side chain into the secondary alcohol provided the hydroxy ester IV. The corresponding hydroxy acid V was transformed into the S‐(2‐pyridyl) carbothioate which cyclized under the influence of silver ions to yield 68% of 4‐benzyl‐lasiodiplodin (VI). Removal of the benzyl group by catalytic hydrogenation gave (±)‐lasiodiplodin (VII).
Crystal Structure and Molecular Conformation in Solution of 6‐Phenyl‐ and 11‐Phenyl‐3,4,6,11‐tetrahydro‐2H‐pyrimido [2,1‐c] [2,4]benzothiazepine. 26th Communication on Seven‐Membered Heterocycles
Authors: Weber Hans Peter , Petcher Trevor J. , Loosli Hans Rudolf 
Published: December 2004

Die Kristallstruktur und die molekulare Konformation in Lösung von 6‐Phenyl‐ und 11‐Phenyl‐3,4,6,11‐tetrahydro‐2H‐pyrimido‐[2,1‐c] [2,4]benzothiazepinDie Röntgenstrukturanalysen der beiden Titelverbindungen ergaben, dass die Konformation der Thiazepinringe zwar voneinander verschieden sind, dass aber in beiden Verbindungen der Phenylsubstituent in axialer Stellung steht. Interpretationen der 1H‐NMR.‐Daten legen die Vermutung nahe, dass die bevorzugten Konformationen des siebengliedrigen Ringes in Lösung in beiden Molekeln mit den im Kristall beobachteten Konformationen identisch sind.
Synthèse de céphalosporine‐lactones
Authors: Petrzilka Théodor , Prasad Kapa K. , Schmid Gérard 
Published: December 2004

AbstractCondensation of azetidinones 2a and 2b with mercaptan 3 gave respectively compound 10 or a 1:1 mixture of 17 and 17′. Bromination of 10, afforded cis and trans‐bromohydrins 13a and of 17 and 17′ cis and trans‐bromohydrins 18a. Acetylation and reduction with zinc and acetic acid of these bromohydrins gave cephems 4a or 4b and 4b′ respectively.
Chemical selectivities disguised by mass diffusion. V. Mixing‐disguised azo coupling reactions. 6th communication on the selectivity of chemical processes
Authors: Bourne John R. , Crivelli Eros , Rys Paul 
Published: December 2004

AbstractThe results of this study show that, for given initial and boundary conditions, four parameters are sufficient to describe the final product distribution of azo coupling reactions influenced by mixing. This is in agreement with the prediction of the mixing‐reaction model developed previously [4] [5]. In order to explain the pH‐dependence of the measured mixing‐disguised product distribution, it is necessary to assume that a selectivity‐determining, local pH‐gradient exists even though the solution is macroscopically buffered.
Catalytic C(1), C(2)‐Bond Cleavage of Long‐Chain Aliphatic Alcohols and ω‐Phenylalkyl Alcohols
Authors: Baiker Alfons , Richarz Werner 
Published: December 2004

AbstractA catalytic one step procedure for the C(1), C(2)‐bond cleavage of long‐chain aliphatic alcohols and ω‐phenyl alcohols has been investigated, using as examples decanol, dodecanol, hexadecanol, benzyl alcohol, 2‐phenylethanol and 3‐phenyl‐propanol. The reactions, which were carried out in a continuous flow tubular reactor using a Ni/Cu catalyst, showed good activity and selectivity with respect to the cleavage products. On the basis of the experimental studies a reaction scheme for the heterogeneous catalytic C(1), C(2)‐bond cleavage of the alcohols is suggested.