bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthese von 4‐halogensubstituierten Analogen von Trimethoprim
Authors: Kompis Ivan , Wick Alexander 
Published: December 2004

The Synthesis of 4‐Halogen‐substituted Analogs of TrimethoprimThe four 2,4‐diamino‐5‐(4‐halo‐3,5‐dimethoxybenzyl)pyrimidines 20a‐d have been synthesized along known routes, i.e. form the corresponding aldehydes 17a‐d via the aminomethylidene‐derivatives 18a‐d and 19a‐d, respectively (Scheme 4). All four aldehydes were prepared from a common intermediate, methyl 4‐amino‐3,5‐dimethoxybenzoate (3), which was obtained from dimethyl 2,6‐dimethoxyterephthalate (2) and hydroxylamine in a regioselective Lossen‐type rearrangement mediated by polyphosphoric acid (Scheme 1). Under identical rearrangement conditions 2,6‐diethoxyterephthalate (12) led, in addition to the amine 14, to the benzoxazolone 15 (Scheme 2). Scope and mechanism of this reaction are discussed. ‐ The antimicrobial activity of the diamino‐pyrimidines 20a‐d, expressed as the inhibition of E. coli‐dihydrofolate reductase, has been measured and compared with that of trimethoprim (1), an established antimicrobial agent.
2‐(Trimethylsilyl)äthylester als Carboxylschutzgruppe; Anwendung bei der Synthese des (−)‐(S)‐Curvularins
Authors: Gerlach Hans 
Published: December 2004

2‐(Trimethylsilyl)ethyl Esters as Carboxyl Protecting Group; Application in the Synthesis of (−)‐(S)‐CurvularinThe mould metabolite curvularin (VIII) has been synthesized with the help of a new carboxyl protecting group that can be removed selectively with fluoride ions. 2‐(Trimethylsilyl)ethyl 7‐hydroxy‐octanoate (III) was acylated with 3,5‐dibenzyloxy‐phenacetyl chloride (IV) to form V with two different ester groups. Tetrabutyl‐ammonium fluoride in tetrahydrofuran cleaved the 2‐(trimethylsilyl)ethyl ester in V selectively to form the carboxylate anion of VI together with ethylene and trimethylsilyl fluoride. Curvularin dibenzyl ether (VII) was formed by intramolecular acylation of VI. Removal of the benzyl ether groups in VII by hydrogenolysis led to (±)‐curvularin (VIII). The naturally occurring (−)‐enantiomer was formed when (+)‐(S)‐III served as starting material.
Action du monoxyde d'azote sur le phényléthylène et sur quelques arylalcènes
Authors: Tuaillon Jacques , Perrot Roger 
Published: December 2004

AbstractNitric oxide reacts with phenylethylene and arylalkenes under the action of sunlight and at room temperature giving dimeric nitronitroso compounds prouved by IR. spectroscopy (see Table 2) and the corresponding nitroolefins. The main gaseous product is nitrogen as prouved by gaz liquid chromatography (see Table 1). The dimeric nitronitroso compounds can also be obtained by the reaction of dinitrogen trioxide with olefins. The structure of the nitronitroso compounds was further discussed. They may be reduced to give monoamines corresponding to the nitrogroup and may be also converted into nitroolefins.
Structures of Addition Products of Acetylenedicarboxylic Acid Esters with Various Dinucleophiles. An application of C, H‐spin‐coupling constants
Authors: Vögeli Ulrich , von Philipsborn Wolfgang , Nagarajan Kuppuswamy , Nair Mohan D. 
Published: December 2004

AbstractHeterocyclic compounds obtained by addition of acetylenedicarboxylic acid esters to thioureas, cyclic amidines and o‐difunctionalized aromatic systems have been studied by 13C‐NMR. In particular, C, H‐spin‐coupling constants over two and three bonds were used to differentiate between the various constitutional isomers and to establish the configuration of trisubstituted exocyclic C, C‐double bonds. The configurational significance and diagnostic value of vicinal cis and trans C,H‐spin coupling is again demonstrated in the present series.
Derivate des 5, 9‐Methano‐6, 7,8, 9‐tetrahydro‐5 H‐benzocycloheptens und Umlagerungen zum 1, 4‐Äthano‐1,2,3,4‐tetrahydronaphtalin‐System
Authors: Stoll André P. , Loosli Hans‐Rudolf , Niklaus Peter , Zardin‐Tartaglia Therese 
Published: December 2004

Derivatives of 5,9‐Methano,7,8,9‐tetrahydro‐5H‐benzocycloheptene and Rearrangements to the 1,4‐Ethano‐I,2,3,4‐tetrahydronaphthalene SystemReduction of the oxime 2 with Raney alloy gives the amine 3a, with AlH3 a mixture of the isomeric amines 3a and 3b, whilst LiAlH4 yields the aziridines 4a and 4b. The bicyclo[3.2.1]octane 4b rearranges under acidic conditions to the bicyclo[2.2.2]octane 5. The olefin 7 can be converted to the aminoalcohol 9 via the epoxide 8 and to the amine 13 using iodine isocyanate: the carbon skeleto. remains intact. However, treatment of the olefin 17 with iodine isocyanate leads to the bicyclo[2.2.2]octanes 21 and 24 in which a skeletal rearrangement has taken place. The configuration was determined by NMR. and X‐ray analysis.
Diterpenoide Drüsenfarbstoffe aus Labiaten: 6 neue p‐Chinomethane aus Plectranthus parviflorus WILLD
Authors: Rüedi Peter , Eugster Conrad Hans 
Published: December 2004

Leaf‐gland Pigments: 6‐Novel p‐Quinomethanes of the Abietane Series from Plectranthus parviflorus WILLDThe above mentioned plant accumulates in its red coloured leaf‐glands a complex mixture of strongly dehydrogenated abietanols. They were separated (with difficulties) to yield 6 novel compounds. Spectroscopic and chiroptic data show them to be esters of either 11, 19‐dihydroxy‐ or 2 α, 11‐dihydroxy‐abieta‐5, 7, 9 (11), 13‐tetraen‐12‐one 2a and 3a, respectively. Specifically, the 19‐O‐p‐hydroxybenzoate (2d) parvifloron C, the 19‐O‐vanilloate (2c) parvifloron B, the 19‐O‐p‐hydroxy‐benzoate (2d) parvifloron C, the 19‐O‐3′,4′‐dihydroxybenzoate (2e) parvifloron E, the 2 α‐O‐p‐hydroxybenzoate (3b) parvifloron D, and the 2 α‐O‐3′,4′‐dihydroxy‐benzoate (3c) parvifloron F. Reduction by LiAlH4 splits the ester function and reduces the p‐quinomethane to a colourless pyrocatechol derivative which, by air oxidation, regenerates the red p‐quinomethane system of 2a and 3a.
Basenkatalysierte Cyclisierungen von 2‐(2‐Propinyl)oxybenzamiden
Authors: Scherrer Veronica , Jackson‐Mülly Martha , Zsindely Janos , Schmid Hans 
Published: December 2004

Base Catalysed Cyclizations of 2‐(2‐Propynyl)oxy‐benzamide Systems2‐(2‐Propynyl)oxy‐benzamides were cyclized under base catalysis to 6‐ or 7‐membered ring compounds, depending on the reaction conditions. Treatment of 2‐(2‐propynyl)oxy‐benzamide (10) with sodium methylsulfinylmethanide (NaMSM) in DMSO gave two isomeric oxazepinons 11 (34%) and 12 (7%), while the transformation with sodium‐2‐propanolate in 2‐propanol afforded the oxazinone 13 (34%) and with lithium cyclohexyl‐isopropylamide (Li‐CHIP) in N‐methylpyrrolidone 11 (48%) exclusively (Scheme 4). N‐Methyl‐2‐(2‐propynyl)‐oxy‐benzamide (14) behaved similarly. In the reaction of 14 with sodium 2‐propanolate in 2‐propanol yielding the benzoxazinone 16, the allenyloxy‐benzamide 17 could be isolated as an intermediate (Scheme 5). The N‐phenyl‐compounds 18 and 22 treated with NaMSM/DMSO were converted to 3‐anilino‐2‐methyl‐benzo‐ and naphtho‐pyran‐4‐ones, respectively (Schemes 6 and 7). The mechanisms for these reactions are discussed (Schemes 8, 9 and 10).
Tris (methylidene)‐cyclopropane (“[3]Radialene”). Part 2. Electronic states of the molecular cation and revised UV.‐absorption spectrum of the parent neutral
Authors: Bally Thomas , Haselbach Edwin 
Published: December 2004

AbstractThe photoelectron spectrum of tris (methylidene)‐cyclopropane 1 (“[3]radialene”) is reported and the electronic states of 1+ assigned. Jahn‐teller activity in the degenerate states of 1+is discussed. Differences in the Franck‐Condon profile of the first PE band and the Rydberg series in the Vacuum‐UV./UV. absorption spectrum indicate for the Rydberg series (n=3) a 1A″2‐species, which supports earlier tentative proposals. The high intensity absorption in the 5.5 eV‐6 eV energy range of the latter spectrum recorded earlier are definitely due to impurities. The vibrational fine structure of a weak band system around 5.5 eV in our spectrum suggests for this transition S0→S2(1A′1), which is dipole forbidden but borrows intensity from S1(1E′) trough vibronic coupling via an e′‐mode. From vapor pressure measurements ε(λmax=289 nm) = 9390± 1170 for gaseous 1 was found.
Synthese von 3‐Dimethylamino‐3a,4,5,7a‐tetrahydro‐1H‐iso‐indol‐1‐onen durch intramolekulare Diels‐Alder‐Reaktion
Authors: Widmer Ulrich , Heimgartner Heinz , Schmid Hans 
Published: December 2004

Synthesis of 3‐Dimethylamino‐3a,4,5, 7a‐tetrahydro‐1H‐isoindol‐1‐ones by Intramolecular Diels‐Alder ReactionThermolysis of N2‐acylamidines, the acyl group of which derives from an α,β,γ,δ‐unsaturated carboxylic acid (2, 5–7), yields 3‐dimethylamino‐3a,4,5,7a‐tetrahydro‐1H‐isoindol‐1‐ones (3,8–10, Schemes 1 and 3) in 63–78%. Only the thermodynamically controlled cis‐fused ring system is formed. The starting materials are readily available by the reaction of 3‐dimethylamino2H‐azirines (1 and 4) and carboxylic acid chlorides.
Reduktionsgrad in Photoredox‐Systemen
Authors: Calzaferri Gion , Grüniger Hans‐Rudolf 
Published: December 2004

Reduction Degree in Photoredox‐SystemsThe reduction degree is in many photoredox systems an invariant under irradiation. Therefore it represents an important degree of freedom in these systems. It is possible to define the reduction degree in such a systematic way, that it may also be applied for discussing complicated systems. It would be helpful to have selective electrode material for the examination of photoredox systems. We have succeeded in finding a selective electrode material for the iron in the iron/thionin system as well as in the iron/iodine system.
Spectra of Organic Molecules in Thin Films
Authors: Swalen J. D. , Tacke M. , Santo R. , Rieckhoff K. E. , Fischer J. 
Published: December 2004

AbstractIn order to investigate molecules and their interactions at interfaces we have developed a new spectroscopic technique based on integrated optics. A significant increase in sensitivity has been predicted and observed. We report here the details of the method and some preliminary spectra of organic dye molecules on thin films.
Partial Syntheses of Methyl Dehydrojasmonate and Tuberolactone
Authors: Dubs Paul , Stüssi Rita 
Published: December 2004

AbstractThe natural products methyl dehydrojasmonate (1) and tuberolactone (2) have been synthesized from methyl jasmonate (3) and jasmolactone (4) resp., via sulfenylation‐sulfoxide pyrolysis.
Über die Herstellung von Äther der enantio‐14, 15‐Dinorlabdan‐Reihe aus Eperusäure
Authors: Dey Ashesh Kumar , Wolf Hans Richard 
Published: December 2004

The Conversion of Eperuic Acid into Ethers of the enantio‐14, 15‐Dinorlabdane Series5 and 6 are strongly odiferous substances of the ambra‐type. Their enantiomers 7 and 8, hitherto unknown, have been synthesized from eperuic acid (4) and their olfactory properties compared with those of 5 and 6. 4 was esterified by CH2N2 and dehydrogenated with (C6H5Se)2/H2O2 to the α,β‐unsaturated ester 9 (61%). Oxidation by KMnO4 in acetone yielded the ketone 3 (60%). Epoxidation followed by treatment with acid converted 3 into the acetals 7 (61%) and 8 (14%). 7 and 8 differ from 5 and 6 in odor intensity, and 6 and 8 show slightly different odor quality.
Selective Removal of the o‐Nitrophenylsulfenyl Protecting Group in Peptide Synthesis
Authors: Tun‐Kyi Aung 
Published: December 2004

Abstract2‐Thiopyridone (2‐mercaptopyridine, 1) was found to be a very suitable reagent for removing the Nα‐o‐nitrophenylsulfenyl (NPS‐) group in both conventional and solid‐support peptide synthesis. A 3‐ to 5‐molar excess of the reagent together with an equivalent amount of glacial acetic acid in methanol, dimethylformamide, or methylene chloride produces the soluble, stable mixed disulfide, 2‐nitrophenyl 2‐pyridyl disulfide (2), and the Nα‐deprotected amino‐acid or peptide. The yields are quantitative in less than 5 min if all educts are dissolved, in about 20 to 30 min in solid‐support synthesis. No modifications of either the indole side‐chain of tryptophan or of a series of side‐chain protecting groups, in particular of the t‐butyl type, are produced. No adverse side‐reactions (insoluble disulfides) were observed. The procedure is illustrated with a series of amino‐acid derivatives and with the solid‐support synthesis of [5‐leucine]‐enkephalin.
Rhodium (I)‐katalysierte Reaktionen der [2+4]‐Cycloaddukte aus 3,4‐Dimethoxyfuran und Acetylendicarbonsäure‐estern
Authors: Iten Peter Xaver , Eugster Conrad Hans 
Published: December 2004

[2+4]‐Cycloaddition Products of 3,4‐Dimethoxyfuran with Acetylenedicarboxylates and Their Transformations under the Influence of Rhodium(I) Catalysts3,4‐Dimethoxyfuran (1) readily reacts with acetylenedicarboxylates (2) at room temperature in a [2+4]‐cycloaddition to give a mono‐(3) and several di‐addition products. 90% of the latter consists of the endo‐exo compound 4. Under the influence of catalytic amounts of [Rh(CO)2Cl]2 the mixture of mono‐ and di‐adducts in methanolic solution is smoothly transformed into endo‐5,5,6‐trimethoxy‐7‐oxabicyclo [2.2.1]hept‐2‐ene‐2,3‐dicarboxylateAlle Verbindungen sind racemisch. Die Formeln stellen jeweils nur ein Enantiomeres dar.

(5)
, 3‐hydroxy‐4,5‐dimethoxyphthalate (
6
) and (I
R
*, 2
S
*, 4
R
*, 5
R
*, 7
R
*, 11
R
*, 12
R
*) ‐5,8,8,9,12‐pentamethoxy‐3,6‐dioxatetracyclo [5.3.1.1
2,5
. 0
4,11
]dodec‐9‐ene‐1,11‐dicarboxylate

(
7
).
Activity, Selectivity, Decay and Long‐Term Behaviour of Amination Catalysts
Authors: Baiker Alfons , Richarz Werner 
Published: December 2004

AbstractA survey of the activity and selectivity of several catalysts for the amination of long‐chain aliphatic alcohols with dimethylamine is given. The best results were obtained with Cu‐catalysts whose long‐term behaviour was investigated. The main reasons for catalyst decay are the irreversible adsorption of dimerization products and the thermal diffusive fusion of Cu‐crystallites.
A Theoretical Study of Complex Formation between Formaldehyde and Lithium
Authors: Ha Tae‐Kyu , Wild Urs P. , Kühne René O. , Loesch Charles , Schaffhauser Thierry , Stachel Johanna , Wokaun Alexander 
Published: December 2004

AbstractAb initio SCF and CI calculations on the cationic and neutral complexes of formaldehyde and lithium are reported. For the cationic complex CH2O/Li+, the stabilization energy of 41.7 kcal/mol obtained from the SCF calculation increases to 51.6 kcal/mol if a configuration interaction is introduced. For the neutral complex CH2O−/Li+, the C2v‐conformer of the 2A1‐state with the equilibrium bond distances of d(CO) = 1.23 Å and d (OLi) = 1.90 Å is calculated to be more stable than the 2B1‐state with d (CO) = 1.34 Å, and d (OLi) = 1.65 Å. Charge transfer and polarization effects upon complex formation are discussed.
Ruspolia hypercrateriformisM.R.: Isolierung und Strukturaufklärung von neuen Pyrrolidin‐Alkaloiden. 169. Mitt. über organische Naturstoffe
Authors: Roessler Felix , Ganzinger Dietmar , Johne Siegfried , Schöpp Emanuel , Hesse Manfred 
Published: December 2004

Ruspolia hypercrateriformis M.R.: Isolation and Structure Elucidation of New Pyrrolidine AlkaloidsThree new pyrrolidine alkaloids have been isolated from Ruspolia hypercrateriformis, which belongs to the plant family of Acanthaceae. The structure of the alkaloids ruspolinone (1), norruspolinone (2) and norruspoline (3) (Scheme 1) has been elucidated by means of spectroscopic data of the pure compounds and their derivatives, by chemical transformation fo 2 to 1 by methylation, by trans‐formation of 3 and 2 to identical hydrogenation products, and by comparison of degradation products with synthetically prepared model compounds.
Préparation de quelques 4‐nitroisoxazoles à partir de pseudonitrosites de cétones éthyléniques du type chalcone
Authors: Hauff Jean‐Pierre , Tuaillon Jacques , Perrot Roger 
Published: December 2004

The Synthesis of some 4‐Nitroisoxazoles from Pseudonitrosites of ChalconesThe action of dinitrogen trioxide with α,β‐unsaturated ketones of the chalcone type leads to pseudonitrosites (Table 1) which are cyclized to 4‐nitro‐3,5‐diarylisoxazoles (Table 2).
Synthese von zwei natürlich vorkommenden Lactonen mit 10gliedrigen Ringen: (±)‐Phoracantholid J und I
Authors: Gerlach Hans , Künzler Peter , Oertle Konrad 
Published: December 2004

Synthesis of Two Naturally Occurring 10‐Membered Ring Lactones: (±)‐Phoracantholide J and ITwo 10‐membered ring lactones 7 and 11 from the metasternal secretion of the eucalypt longicorn Phoracantha synonyma have been synthesized by the following method. Reaction of the dilithium derivative of 4‐pentynoic acid (3) with 4‐tetrahydropyranyloxy‐1‐pentylbromide (2), followed by removal of the protecting group and by esterification with diazomethane, gave methyl 9‐hydroxy‐4‐decynoate (4; s. Scheme 1). Partial hydrogenation of the triple bond in 4 with Lindlar palladium catalyst, followed by saponification lead to cis‐9‐hydroxy‐4‐decenoic acid (6). The 9‐hydroxydecanoic acid (9) was synthesized by addition of methyl magnesium iodide to methyl 8‐formyloctanoate (8) followed by saponification (s. Scheme 2). The hydroxy acids 6 and 9 were converted into the S‐(2‐pyridyl) thioesters and cyclized in dilute benzene solution under the influence of silver ions to yield (±)‐phoracantholide J (7) and I (11) in 74 and 71% yield, respectively.
5, 7‐Dihydroxy‐8‐methoxy‐chroman‐4‐on aus dem Zwiebelwachs von Eucomis comosa
Authors: Heller Werner , Tamm Christoph 
Published: December 2004

5, 7‐Dihydroxy‐8‐methoxy‐chroman‐4‐one from the Bulb Wax of Eucomis comosaFrom the bulb wax of Eucomis comosa (HOUTT.) WEHRH. (Liliaceae) 5, 7‐dihydroxy‐8‐methoxy‐chroman‐4‐one (1) was isolated. The structure was confirmed by direct comparison with a synthetic specimen. 1 is the first natural chroman‐4‐one which is unsubstituted in the heterocyclic ring.
The Dianions of Phenanthrene and 1,2,3,4‐Dibenzocyclooctatetraene
Authors: Müllen Klaus 
Published: December 2004

AbstractThe dianions of phenanthrene and 1,2,3,4‐dibenzocyclooctatetraene have been prepared by metal reduction of the neutral compounds and characterized via the study of their 1H‐ and 13C‐NMR. spectra. A description of the charge distribution can be achieved which is consistent with both MO‐models and the spin density distribution of the corresponding radical anions. Thus, the dianion of 1,2,3,4‐dibenzocyclooctatetraene appears as a π‐bond delocalized species having its excess charge mainly localized in the eight membered ring.
A Chemical Study of Virginia Tobacco Flavour (Nicotiana tabacum L.) II. Isolation and synthesis of cis‐2‐isopropenyl‐8‐methyl‐1,2,3,4‐tetrahydro‐1‐naphthalenol and 3‐isopropenyl‐5‐methyl‐1,2‐dihydronaphthalene
Authors: Demole Edouard , Enggist Paul 
Published: December 2004

AbstractGas liquid chromatography allowed isolation of the novel cis‐2‐isopropenyl‐8‐methyl‐1,2,3,4‐tetrahydro‐1‐naphthalenol (A) and its dehydration product, 3‐isopropenyl‐5‐methyl‐1,2‐dihydronaphthalene (B), from two small subfractions of Virginia tobacco condensate. Both these norsesquiterpenes were identified on spectral grounds and synthesized from 1‐methylnaphthalene in a way (9 steps) that also afforded the «non‐natural», trans‐alcohol A′. The possible biogenesis of A and B in tobacco is briefly outlined.
Metal Complexes with Macrocyclic Ligands. IX. Synthesis and properties of a new class of branched N4‐macrocycles with an additional ligating group in the side chain
Authors: Lotz Tobias J. , Kaden Thomas A. 
Published: December 2004

AbstractIn the presence of Ni2+ the template reaction between 2,6‐diacetylpyridine and 4‐(2‐dimethylaminoethyl)‐ or 4‐(2‐hydroxyethyl)‐1, 7‐diamino‐4‐azaheptane yields the complexes of either the open‐chain ligand (3 and 11) or of the macrocycle (4 and 12). Reduction of the imino group in 4 and 12 with PtO2/H2 gives 5 and 13, respectively. In the case of the dimethylamino derivative 5 a mixture of at least four isomers was obtained. These were partially separated by chromatography on Sephadex SP‐25 cation exchanger. Through demetalation of the Ni2+ complexes by cyanide the new macrocycles 7 and 14 were isolated, from which the corresponding Zn2+ and Cu2+ complexes were prepared.The macrocyclic Ni2+‐complexes 4, 12, 5 and 13 can exist in two forms depending on the pH of the solution. At low pH protonation of the dimethylamino or hydroxy group in the side chain occurs. The metal ion is then bound to the four nitrogen atoms of the macrocycle in a square planar ligand field. At higher pH, however, the dimethylamino or hydroxy group (the last one also in its deprotonated form) can coordinate to one of the axial positions, whereby pseudooctahedral coordination geometry is induced. This reaction can be quantitatively described by a reversible acid‐base equilibrium, the pKH of which greatly depends on the nature of the functional group, the degree of unsaturation of the macrocycle and the metal ion.The acid‐base reaction and the concomitant structural change are a direct consequence of the unique combination of the rigid and kinetically stable structure of the macrocycle and of the flexible and kinetically labile functional group of the side chain.
Einfluss der Lipophilie von 3, 6‐Dioxakorksäurediamiden auf ihr Verhalten als Ionophore
Authors: Bissig René , Oesch Urs , Pretsch Ernö , Morf Werner E. , Simon Wilhelm 
Published: December 2004

Influence of the lipophilicity of 3,6‐dioxaoctanedioic diamides on their ion carrier propertiesA series of lipophilic 3,6‐dioxaoctanedioic diamides (potential ionophores for Ca2+) have been prepared. With increasing lipophilicity the ionophoric behavior of these ligands vanishes. This loss is shown to be due to kinetic limitations in the exchange reactions between aqueous phase and membrane phase.
Réactions chimiques oscillantes. II. Comportement de la «période d'induction» dans les systémes BrO/Ce4+/Cyclohexanone et BrO/Ce4+/Cyclopentanone
Authors: Farage Vincent J. , Janjic DéSimir 
Published: December 2004

Oscillating Chemical Reactions. 11. Behaviour of the “induction period” in the BrO/Ce4+/Cyclohexanon and BrO/Ce4+/Cyclopentanon systems
The addition of α‐monobromoketone, one of the products of reaction of the BrO3−/Ce4+/Cyclohexanon (S1) and BrO3−/Ce4+/Cyclopentanon (S2) oscillating systems, decreases and even suppresses the induction period (τind.) in the case of S2.Such is not the case with S1: τind. increases and the oscillations can even be completely inhibited.
The order of addition of the reagents and the time lapse (tadj.) preceding the addition of the last of them influences τind., particularly when the last reagent added is Ce4+.
In our experimental conditions, the inhibition of the oscillatory phenomenon by Cl− ions is definite only for | Cl− | ≥ 5,0 · 10−2M (S1) and |Cl−| > 2,5 · 10−3M (S2); for lower concentrations τind. increases with | Cl−|.
Elektrochemische Bildung von Δ1,2‐Norbornen
Authors: Stamm Erich , Walder Lorenz , Keese Reinhart 
Published: December 2004

Electrochemical Formation of Δ1,2‐NorborneneThe electrochemical reduction of 1,2‐dihalogen norbornanes in tetrahydrofuran/furan leads to a mixture of two isomeric cycloadducts 6 and 7. The ratio of these adducts corresponds to those which have been found in reductive bisdehalogenation of 1 and 2 by butyllithium.
“Push‐Pull”‐Acetylene für die Peptid‐Synthese
Authors: Lienhard Ulrich , Fahrni Hans‐Peter , Neuenschwander Markus 
Published: December 2004

“Push‐Pull” Acetylenes as Reagents for Peptide SynthesisA series of ‘push‐pull’ acetylenes 1 is easily available from the corresponding “push‐pull” olefins by a simple bromination‐dehydrobromination sequence. The versatility of the acetylenes with regard to peptide synthesis is discussed.