bluuebunny/crossref_metadata_2025_split huggingface dataset:
Recherches dans la série des cyclitols XLIV. Synthèses de cycloses dérivés du cyclopentane
Authors: Cocu F. G. , Posternak Th. 
Published: December 2004

AbstractThe conversion to free ketoses by transketalisation of ethylene‐ketal and/or isopropylidene derivatives of polyhydroxy‐cyclopentanones has been investigated. The preparation of 2, 3‐dihydroxy‐cyclopentanone and of 2, 3‐dihydroxy‐cyclopentenone has been described.
The Photodecarbonylation of α‐Aryl Aldehydes: 1‐Formyl‐1‐methyl‐indan and heterocyclic analogues
Authors: Wolf H. , Gonzenbach H.‐U. , Müller K. , Schaffner K. 
Published: December 2004

AbstractThe singlet photodecarbonylation of the indanyl aldehyde 7 – a benzohomologue of laurolenal (1) and also a conformationally rigid ‘out‐of‐plane’ analogue of the α‐aryl aldehyde 4 previously studied [5] [6], – and of the heterocyclic derivatives 8–10 in degassed solutions, has been investigated. While 7 decarbonylates uniformly to the niethylindan 30 in close analogy to the examples studied previously, 8 and 9 decompose to the corresponding Δ2‐unsaturated compounds 33, 35 in addition to decarbonylation to 32, 34. The results provide an independent indication for intermediate photolytically formed radical pairs (a) in which heteroatoms facilitate radical removal of hydrogen from C(2), and thus introduce disproportionation to give unsaturated products + CH2O, competing with the otherwise exclusive alternative affording saturated products +CO.
Extraction liquide‐liquide par des esters alkylphosphoriques. II. Extraction des nitrates de béryllium et des autres alcalino‐terreux par le tri‐n‐butylphosphate
Authors: Brunisholz G. , Hirsbrunner W. , Aerny J. 
Published: December 2004

AbstractThe solvent extraction systems Be(NO3)2HNO3H2OTBP/kerosene and M(NO3)2H2OTBP/kerosene (TBP = tri‐n‐butylphosphate, M = Be, Mg, Ca and Sr) have been studied. The alkaline earths elements are poorly extracted. Only very high acidities allow better extraction of beryllium. The sequence of extraction of the alkaline earths elements by the TBP depends on the concentration of the cations and is Ca > Be > Sr > Mg if the metal concentration is lower than 2 M.
Quinazolines et benzodiazépines‐1, 4. LVI. Oxadiazolo‐1, 2, 4[4, 5‐d] benzodiazépines‐1, 4: synthése et passage aux oxazolo [3, 2‐d] benzodiazépines‐1, 4
Authors: Jaunin R. , Oberhänsli W. E. , Hellerbach J. 
Published: December 2004

AbstractThe tricyclic derivatives 4–14 can be prepared by 1, 3‐dipolarcycloaddition of the appropriate nitrile oxides on the corresponding 1, 4‐benzodiazepines. NaBH4 reduction of the esters 12–14 was found to proceed very readily; starting from 13 it is possible, by proper reaction conditions, to get in good yield either the monoalcohol 19 or the aminodiol 20. The alcohols 19 and 23 undergo an acid‐catalysed rearrangement which produces the amidoximes 24 and 26. The determination of the structure of 24 by X‐ray diffraction analysis is also presented.
Vier neue Metabolite von Giberella zeae: 5‐Formyl‐zearalenon, 7′‐Dehydrozearalenon, 8′‐Hydroxy‐ und 8′‐epi‐Hydroxy‐zearalenon
Authors: Bolliger G. , Tamm Ch. 
Published: December 2004

AbstractFrom cultures of Gibberella zeae ergosterol, zearalenone (1) and hitherto unknown minor metabolites, i.e.. 5‐formyl‐zearalenone (6), 7′‐dehydrozearalenone (8), 8′‐hydroxyzearalenone (9) and 8′‐epi‐hydroxyzearalenone (11) were isolated. The production of zearalenone and its congeners proved to be very strongly dependent on the conditions of culture.5‐Formyl‐zearalenone (6) as well as 3‐formylzearalenone (4) were synthesized from zearalenone (1) and characterized by the di‐O‐methyl derivatives 7 and 5 respectively. The structure of 7′‐ dehydrozearalenone (8) was deduced from spectral data. The di‐O‐methyl derivatives 10 and 12 respectively of the two corresponding epimeric 8′‐hydroxy derivatives 9 and 11 yielded the same β‐diketone 13. The keto‐enol equilibrium of 13 was studied.
Zur Kinetik der Perkow‐Reaktion
Authors: Konecny J. , Dousse R. , Rosales J. 
Published: December 2004

AbstractThe Perkow reaction of CH3COCHClCONHCH3 with (CH3O)3P is first order in both reactants. The reaction rates, the activation energies and the high negative entropies of activation have comparable values in benzene and in acetonitrile solutions.
Kinetic Investigation of a (6 + 4) Cycloaddition
Authors: Tanida Hiroshi , Pfaendler H. R. 
Published: December 2004

AbstractKinetics of the [6+4] Cycloaddition of tropone to cyclopenta‐1, 3‐diene were investigated. It was concluded that the mechanism of this cycloaddition is similar to that of the classic Diels‐Alder reaction.
Pyrazines. 2ème communication [1]. II. Synthèse de dihydro‐6,7‐5H‐cyclopenta[b]pyrazines alkylées
Authors: Flament Ivon , Sonnay Philippe , Ohloff Günther 
Published: December 2004

AbstractAlkyl‐5H‐6,7‐dihydrocyclopenta[b]pyrazines are prepared by condensation of cyclopentenolones with alkylenediamines or of aliphatic α‐diketones with 1,2‐diaminocyclo pentanes. Products so obtained were dehydrogenated using palladium on activated charcoal, or copper chromite. NMR. and mass spectra are given for 21 bicyclic pyrazines and intermediates, and their IR. spectra are compared.
Synthèse du tétraéthoxycarbonyl‐1,1,6,6‐cyclodécadiyne‐3,8
Authors: Etournaud Alain , Wyler Hugo 
Published: December 2004

AbstractA cyclisation of 1‐bromo‐5,5,10,10‐tetraethoxycarbonyl‐2,7‐decadiyne (9b) using NaH in dilute solution gives 1,1,6,6‐tetraethoxycarbonyl‐cyclodeca‐3,8‐diyne (8) in 17,6% yield. 9b is prepared by condensation of 1,1,6,6‐tetraethoxycarbonyl‐3‐hexyne with 1,4‐dibromo‐2‐butyne.
The Nature of the Azonium Cation as Evidenced by X‐Ray Photoelectron Spectroscopy
Authors: Haselbach Edwin , Henriksson Anita , Schmelzer Andreas , Berthou Hervè 
Published: December 2004

AbstractThe question of the classical or non‐classical nature of aryl‐substituted azonium cations as well as of the pyridazinium cation has been settled by X‐ray photoelectron spectroscopy in favour of the classical structure. The relative magnitude of the observed N1s binding energies is reasonably well reproduced on the basis of the theoretically calculated charge structure of these ions. The relative magnitude of the crucial intramolecular potential terms, appearing in the theoretical treatment, is also suggested from PMR.‐investigations on protonated azo‐compounds. The electronic structure of these species is compared with that implied by commonly accepted classical valence structures and parallels to carbo‐cations are drawn. MINDO/2 calculations of the proton affinities of azo‐compounds, considering structurally different conjugate acids, also support a classical azonium cation structure. The gas phase basicity of azobenzene is predicted to be higher than that of azomethane.
Observation of the Neophyl Radical Rearrangement by Electron Spin Resonance Spectroscopy
Authors: Hamilton Edwin J. , Fischer Hanns 
Published: December 2004

AbstractThe rearrangement of the 2‐methyl‐2‐phenylpropyl (or neophyl) radical 1 to the 1‐methyl‐1‐benzylethyl radical 2 is observed by ESR. spectroscopy during photolysis of di‐t‐butylperoxide in t‐butylbenzene at 270–360 K. The energy of activation of the rearrangement is determined to be (43 ± 9) kJ mol−1.
Strukturanalyse von Scillicyanosid‐pentahydrat. 58. Mitteilung über Herzglykoside [1]
Authors: Jaunin André , Weber Hans Peter , Wartburg Albert Von 
Published: December 2004

AbstractThe crystal structure of the steroidal glycoside scillicyanosid‐pentahydrate has been determined by X‐ray analysis. The rings of the steroid backbone are A/B cis, B/C trans, and C/D cis fused, the six substituents are all in β‐position (5β‐D‐gluco‐pyranoside, 10β‐aldehyde, 13β‐methyl, 14β‐hydroxy, 16β‐acetoxy, and a 17β‐lactone ring). The crystal structure displays a complex system of hydrogen bonds between the five water molecules and the various oxygen functions in the steroidal glycoside. There are no intramolecular hydrogen bonds. 624 structural parameters were refined to an R‐value of 0.059 with 1907 significant structure factors.
3‐Chlor‐4,5‐dihydrofuran ‐ ein nützlicher Synthesebaustein
Authors: Schlosser Manfred , Schaub Bruno , Spahic Bojana , Sleiter Giancarlo 
Published: December 2004

Abstract3‐Chloro‐4,5‐dihydrofuran can be easily substituted in the 2‐position by metalation with butyllithium followed by treatment with an electrophilic reagent. The resulting derivatives may be dehalogenated to give compounds where the original ring structure is either retained or opened. In the latter case alk‐3‐yne‐1‐ols, and 1‐hydroxy‐4‐alkanones are formed.
Arbeiten über Phosphorsäure‐ und Thiophosphorsäureester mit einem heterocyclischen Substituenten. 7. Mitteilung. Thio‐ und Dithiophosphorsäureester von der Art des GS 13005 mit einem analogen oder homologen heterocyclischen Ring
Authors: Rüfenacht Kurt 
Published: December 2004

AbstractTo complete results presented in this and in previous papers of this series as well as published in patents of other authors a review is given on known and new variations of the heterocyclic moiety in GS 13005 type thio‐ and dithiophosphoric acid esters (1, 2) by modification of the 1,3,4‐thiadiazol‐2(3H)‐one ring 5 and by its replacement by analogue five‐ and homologue six‐membered rings.Among new esters of this type some containing the pyrazolinone ring 3 or a 2‐alkoxy‐4H, 6H‐1,3,4‐thiadiazin‐5‐one ring 10 (homologue of the original 5‐methoxy‐1,3,4‐thiadiazol‐2(3H)‐one ring in GS 13005) show no remarkable pesticidal activity, some others containing a pyrazolering 7 or a 3(2H)‐pyridazinonc ring 8 are moderately to highly active but toxic to inauinials in the same proportion.Attempts to prepare seven‐membered 2‐alkoxy‐ and 2‐alkylthio‐6,7‐dihydro‐l, 3,4‐thiadiazepin‐S(4H)‐ones 11, Z‐rnethoxy‐l,3,4‐thiadiazepin‐S(4H)‐one 12 (ring vinylogue of the original 5‐methoxy‐l,3,4‐thiadIazol‐2(3H)‐one ring in GS 13005) and its 7‐methyl‐derivative have been unsuccessful due to unexpected side reactions, such as: five‐ring closure of 3‐(3‐chloropropionyl)‐thio‐ and ‐dithiocarbazic acid esters 22 to pyrazolidinone derivatives 23, pyrazolinone ring closure of a 3‐(acetoacety1)‐thiocarbazic acid O‐methyl ester derivative 26, bromine attack on sulfur in 3‐(2‐alkenoyl)‐thiocarbazic O‐methyl esters 29 instead of bromine addition at the double bond, and halogen splitting off without ring closure in 3‐(2,3‐dihalogeno‐alkanoyl) ‐thiocarbazic O‐methyl esters 30 prepared by acylation of thiocarbazic acid O‐methyl ester with dihalogeno‐alkanoyl‐chlorides.
Dediazoniations of Arene Diazonium Ions in Homogeneous Solution. Part III: Heterolytic arylations in 2,2,2‐trifluoroethanol ‐ an SN1‐or an SN2‐reaction?
Authors: Burri Peter , Zollinger Heinrich 
Published: December 2004

AbstractBenzenediazonium tetrafluoroborate in 2,2,2‐trifluoroethanol decomposes to give fluorobenzene and phenyl 2,2,2‐trifluoroethyl ether. In the presence of benzene, toluene, trifluoromethyl‐benzene or anisole, the respective biphenyl derivatives are formed in addition to fluorobenzene and the ether. The distribution of the isomeric substituted biphenyls is consistent with an electrophilic substitution. No homolytic products (diazo tars, benzene) are formed. The reaction kinetics clearly show that ether formation and aryl‐dediazoniations are of second‐order type, i.e. that trifluoroethanol and the benzene derivatives mentioned above are rate‐determining factors. It is shown that these results exclude the SN1‐mechanism which is usually assumed for heterolytic dediazoniations; free aryl cations are therefore not involved in these reactions. An SN2‐like mechanism seems to be the most likely, but one involving an encounter complex containing the dissociated benzenediazonium ion is also consistent with the experimental data.
The Oxidation of the Double Bonds of β‐Elemene
Authors: Thomas Alan F. , Vial Christian , Ozainne Michel , Ohloff Günter 
Published: December 2004

AbstractPeracid oxidation of β‐elemene (6) occurs by attack specifically on the isolated [isopropenyl] group at C(4). The structures of the epoxides thus obtained were demonstrated by [conversion] to tetrahydrogeijerol 12 (R  H), which was identical with the substance obtained from geijerone (2) by reduction, first catalytically, then with metal hydride. Ozonolysis of β‐elemene is less specific, attack occurring on the other isopropenyl group (at C(2)) in addition to the one at C(4), and subsequently on the vinyl group (at C(1)). The structures of the ozonolysis products were confirmed by a sequence of reactions from elemol.
Über die Konstitution und die Konfiguration der Rifamycine B, O, S und SV
Authors: Oppolzer Wolfgang , Prelog Vladimir 
Published: December 2004

AbstractDegradation experiments and spectroscopic (UV., VIS., IR., and 1H‐NMR.) evidence have led to the elucidation of the complete constitution and of a part of the configuration of rifamycins B, O, S, and SV.
Dienol‐Benzol‐Umlagerung von Penta‐2,4‐dienyl‐benzocyclohexadienolen
Authors: Greuter Hans , Hansen Hans‐Jürgen , Schmid Hans 
Published: December 2004

Abstract1‐Hydroxy‐2‐methyl‐2‐(penta‐2,4‐dienyl)‐1,2‐dihydronaphthalene (2), on treatment with 0,75N H2SO4 in ether at 0°, underwent a [1s, 2s]‐sigmatropic rearrangement to give 2‐methyl‐1‐(penta‐2,4‐dienyl)‐naphthalene (5), cf. scheme 2. 2‐Hydroxy‐1‐methyl‐1‐(penta‐2,4‐dienyl)‐1,2‐dihydronaphthalene (4) under the same conditions gave 38% of the [1s, 2s]‐product 1‐methyl‐2‐(penta‐2,4‐dienyl)‐naphthalene (6), together with 26% 1‐methylnaphthalene, 21% 1‐methyl‐4‐(penta‐2,4‐dienyl)‐naphthalene (7) and 1% 1‐methyl‐5‐(penta‐2,4‐dienyl)‐naphthalene (8), cf. scheme 2. Most likely the latter two naphthalene derivatives at least are products of an intermolecular process.
Specifically π→π* Induced Photoreactions of α,β‐Unsaturated Ketones: Hydrogen Abstraction by the α‐carbon. (Preliminary Communication)
Authors: Gloor Jean , Bernardinelli Gérald , Gerdil Raymond , Schaffner Kurt 
Published: December 2004

AbstractIrradiations at 254 nm of the α,β‐unsaturated γ‐dimethoxy‐methyl ketone 7 in iso‐octane and t‐butyl alcohol afforded in a specifically π→π*induced process and in high chemical yield the epimeric products 9 and 10. These products were not formed on n→π* excitation of 7 at > 340 nm, but triplet energy transfer to 1,3‐cyclohexadiene could be observed. Photolyses of the hexadeuterio analog 7‐d6 at 254 nm led to the fully deuteriated products (cf. 9‐d6) in both solvents, with stereospecific incorporation of a deuterium atom in position C(1α). The structures of 9 and 10 were determined by an X‐ray diffraction analysis of 9 and chemical correlations of the two products. The structural constraints in 7 demand a hitherto unprecedented direct transfer of a methoxyl hydrogen to the α‐carbon of the excited enone and formation of intermediate 8.
Tétraméthylidène‐2, 3, 5, 6‐oxa‐7‐bicyclo[2.2.1]heptane. (Communication préliminaire)
Authors: Vogel Pierre , Florey André 
Published: December 2004

AbstractPreparation of the title compound (4) is described. An important transannular effect between the two unconjugated s‐cis‐butadiene chromophores is observed by comparison of the UV. spectra of the dimethylidene‐oxanorbornane 3 and the tetramethylidene‐oxanor‐bornane 4.
Antibiotic X‐5108. VI. Relative configuration of the tetrahydrofuran moiety of goldinamine. Preliminary communication
Authors: Maehr Hubert , Williams Thomas H. , Leach Michael , Stempel Arthur 
Published: December 2004

AbstractDie relative Konfiguration des 3,4‐dihydroxy‐2,5‐disubstituierten Tetrahydrofuranrings, ein Strukturelement dcs Antibiotikum X‐5108 und Mocimycin, wurde durch NMR.‐Spektroskopie unter Zuhilfenahme von Modellverbindungen bestimmt. Alle vier Substituenten liegen auf derselben Ringseite.
3‐C‐Hydroxymethyl‐D‐riburonic Acid Synthesis of the Branched‐Chain Uronic Acid and comparison with a carbohydrate component of a naturally occurring bilirubin conjugate
Authors: Blackstock Walter P. , Kuenzle Clive C. , Eugster Conrad H. 
Published: December 2004

AbstractA novel carbohydrate has previously been isolated from human bile as a complex glycoside of bilirubin [1]. This compound has been tentatively identified as 3‐C‐hydroxymethyl‐D‐riburonic acid. To test this structural assignment the proposed branched‐chain uronic acid was synthesized. Gas chromatographic and mass spectrometric comparison of the natural and synthetic materials indicated that the proposed structure, 3‐C‐hydroxymethyl‐D‐riburonic acid, did not apply to thc natural product.
Steroide und Sexualhormone. 253. Mitteilung [1]. Synthetische Versuche in der Limoninreihe II Partialsynthetischer Aufbau der Ringe A und A' von Limonin
Authors: Lüthy Christoph , Schlatter Hans‐Rudolf , Graf Walter 
Published: December 2004

AbstractTwo different synthetic approaches towards compound 16 with the ring A/A'‐partial structure of limonin (1) are described.
Darstellung und Eigenschaften von π‐Cyclopentadienylrhodium‐bis(tert.‐phosphit)‐Komplexen
Authors: Neukomm Heinrich , Werner Helmut 
Published: December 2004

AbstractThe half‐sandwich type compounds C5H5Rh[P(OR)3]2 (R = CH3, C2H5, C6H5, p‐CH3C6H4, p‐ClC6H4) have been prepared from [(P(OR)3)2RhCl]2 and NaC5H5. The NMR. data as well as the IR. and mass spectra of the new compounds will be discussed. The preparation of C5H5Rh(CO)P(OC2H5)3 is also reported.
Oxydation von Allylalkoholen mit Blei(IV)‐acetat
Authors: Ehrenfreund Josef , Zink Markus Peter , Wolf Hans Richard 
Published: December 2004

AbstractLead tetraacetate (LTA) oxidation of the allylic alcohols1, 10, 14and19leads to the formation of the epoxides2, 11, 15and20, products of a novel internal addition reaction of the electron deficient alcohol oxygen to the allylic double bond. In some cases (10, 14) the formation of a new type of acetoxylated enolethers (12, 16) is observed. The LTA oxidation of the allylic dienols21and29gives rise to the formation of the epoxyacetates25and33, products of a similar internal addition reaction. Furthermore, a variety of cyclization products (22, 23, 24, 26, 30, 31, 32and34) has been isolated whose formation requires an isomerisation of the allylictransdouble bond to acisone.
Transpositions de doubles liaisons dep‐menthènes et dep‐menthadiènes catalysées par des bases
Authors: Ferro Alberto , Naves Yves‐René 
Published: December 2004

AbstractThe displacements of double bonds by basic catalysts (N‐lithioethylene diamine with an excess of ethylene diamine, potassiumt‐butylate in dimethylsulfoxide, benzyl‐sodium in boiling xylene) are studied onp‐menthenes andp‐menthadienes. The isomerizations ofp‐menthadienes are accompanied by dehydrogenation. A representative mechanism of isomerization and dehydrogenation according to the catalyst is proposed for limonene.
Azidiniumsalze. 9.Mitteilung [1]. Struktur‐Reaktivitäts‐Beziehungen in Serien quartärer N‐Heteroaromaten: Aciditätskonstanten von 2‐Amino‐cyclimonium‐Ionen als σHet‐Konstanten
Authors: Balli Heinz , Hellrung Bruno , Hinsken Hans 
Published: December 2004

AbstractAus den Aciditätskonstanten kernquartärer Amino‐N‐Heteroaromaten werden σHet‐Konstanten abgeleitet, die in eine lineare Freie Energie‐Beziehung einbezogen werden. Die Synthese der benötigten Amin‐Salze und die Messung ihrer Aciditätskonstanten Kμ (25°, μ = 0,01, Wasser) werden mitgeteilt.
Arbeiten über Phosphorsäure‐ und Thiophosphorsäureester mit einem heterocyclischen Substituenten. 8. Mitteilung. Das Stäubli‐Verfahren, eine Eintopf‐Kondensation von Thiophosphorverbindungen (, XO,S), Aldehyden und Heterocyclen (mit saurer NH‐Gruppe)
Authors: Rüfenacht Kurt 
Published: December 2004

AbstractThe condensation reaction of thiophosphoric compounds 1, aldehydes and heterocycles 3 with an acidic NH‐group in strong mineral acid of specific concentration to asymmetrical compounds 4, called Stäubli procedure, differs from the Mannich‐type reaction catalyzed by weak or dilute acid (aminoalkylation of Hellmann & Opitz) and from the Tscherniac‐Einhorn‐type condensation in concentrated sulfuric acid (amidomethylation of Hellmann). Its main feature is the acidity of the two condensation participants 1 and 3; therefore an attuned concentration of mineral acid is required to activate them each to its individual optimum extent. Their pK difference, however, is sufficient to differentiate their nucleophility and reactivity and to prevent a simultaneous reaction of both of them with the aldehyde provocating side reactions to symmetrical by‐products such as 13, 14 and 15.
8‐Oxabicyclo[5.1.0]octa‐2,4‐dien Thermische und lichtinduzierte Isomerisierung
Authors: Schiess Peter , Wisson Markus 
Published: December 2004

Abstract8‐Oxabicyclo[5.1.0]octa‐2, 4‐diene (1) yields 2,4,6‐heptatrienaldehyde as major primary rearrangement product upon pyrolysis in a flow system between 200 and 300°. Above 500° o‐cresol, benzaldehyde and benzene are obtained. Bicyclo[3.2.0]hept‐2‐en‐7‐one, 2,3‐ and 2, 5‐dihydrobenzaldehyde are shown to be intermediates in this transformation to stable aromatic products. The observed conversions can be rationalized as proceeding mostly through allowed pericyclic reaction steps with heterogeneous, acid catalysed reactions participating to a minor extent. Irradiation of 1 affords 3‐oxatricyclo[4.2.0.02,4]oct‐7‐ene, 2,4,6‐heptatrienal and 3,5‐cycloheptadienone. Upon sensitized irradiation only the latter two compounds are formed.
Vinca Alkaloids XXXIII [1]. Microbiological Conversions of Vincaleukoblastine (VLB, Vinblastine), an Antitumor Alkaloid from Vinca rosea. LINN
Authors: Neuss N. , Mallett G. E. , Brannon D. R. , Mabe J. A. , Horton H. R. , Huckstep L. L. 
Published: December 2004

AbstractThe conversion of VLB using different Streptomycetes led to the isolation of VLB‐ether (3) and Hydroxy VLB (6). The structural assignments have been made by NMR. and high resolution mass spectral data.
13C‐NMR. Spectroscopy of Naturally Occurring Substances. XXXV. Labdanic diterpenes
Authors: Buckwalter Brian L. , Burfitt Ivor R. , Nagel Arthur A. , Wenkert Ernest , Näf Ferdinand 
Published: December 2004

AbstractA total carbon shift analysis of several representatives of the labdane diterpene family of natural products is presented. The shift assignment is based on the prior shift designation of some synthetic trans‐decalin derivatives.
13C‐Kernresonanzspektroskopische Untersuchung der Komplexierung von synthetischen «Carrier»‐Molekeln mit Ca2+‐Ionen
Authors: Büchi Rolf , Pretsch Ernö 
Published: December 2004

AbstractThe complex formation between CaCl2 and the ion carrier ligands 1 and 2 was investigated with 13C‐NMR. spectroscopy. In methanol as solvent, the ligands form complexes with both 1:2‐ and 1:1‐stoichiometry (Ca2+/ligand). In the latter case, apart from solvent molecules, the ligand's two amide carbonyl groups and two ether oxygenatoms probably take part in the coordination of the metal cation. In contrast, when using a non polar solvent (CDCl3), 2 forms only a complex with 1:2‐stoichiometry, whereas 1 may also form a 1:1‐complex in which the ester carbonylgroups participate in the coordination too.
Low Temperature Photochemistry of the Acetone/2‐Propanol System
Authors: Henne Andreas , Fischer Hanns 
Published: December 2004

AbstractDuring UV.‐irradiation of acetone/2‐propanol mixtures at −70° products of photo‐addition of acetone to intermediate enols are formed. The yields of these products exceed the yield of pinacol, the major room temperature product. At −70° the photoadditions are favoured by the long lifetime of acetone enol (≥ 5000 s).
Ionisation Energies and the Electronic Structures of the N‐oxides of Azanaphthalenes and azaanthracenes
Authors: Maier John P. , Muller Jean‐François , Kubota Tanekazu , Yamakawa Masumi 
Published: December 2004

AbstractThe HeI photoelectron spectra of the N‐oxides of the azanaphthalenes 1–5 and of the azaanthracenes 6, 7 were ascertained. The inferred ionisation energies, and the assignments of the spectra, are presented and are discussed in respect to the electronic structures of the N‐oxides and the spectra of the azaderivatives. The data supports the description of the electronic structures of the basic heterocyclic N‐oxides based on PPP SCF calculations and the electronic abrosption spectroscopy.