bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthese eines hochwirksamen Hypertensin II‐amids (L‐Asparaginyl‐L‐arginyl‐L‐valyl‐L‐tyrosyl‐L‐isoleucyl‐L‐histidyl‐L‐prolyl‐L‐phenylalanin)
Authors: Rittel W. , Iselin B. , Kappeler H. , Riniker B. , Schwyzer R. 
Published: December 2004

AbstractThe synthesis of Ileu5‐hypertensin II‐Asp‐β‐amide, L‐Asparaginyl‐L‐arginyl‐L‐valyl‐L‐tyrosyl‐L‐isoleucyl‐L‐histidyl‐L‐prolyl‐L‐phenylalanine, is described. The highly purified octapeptide is 5 to 10 times as active as noradrenaline on the blood pressure of the rat in the experimental set‐up of Peart9), and 2 to 4 times as active as Val5‐ hypertensin I, isolated from bovine plasma3).
Etude spectrographique des complexes formés par les halogénures d'aluminium et le trifluorure de bore. III – Spectre d'absorption infrarouge et pression de vapeur du composé d'addition des fluorures de bore et d'acétyle
Authors: Susz Bernard P. , Wuhrmann Jean‐Jacques 
Published: December 2004

AbstractLe spectre d'absorption infrarouge du composé CH3COF, BF3, à −40° (état solide), donne les fréquences de l'ion (BF4)−. Les fréquences caractéristiques de l'ion (CH3CO)+ ont done pu être déterminées. La fréquence normale ω(CO) de CH3COF ayant disparu du spectre du fluoborate d'acétylium, les auteurs forment l'hypothèse que la fréquence nouvelle intense ω = 2299 em−1 représente cette vibration de valence dans l'ion acétylium. Ils proposent la formule de résonance
equation image
avec faible contribution de la structure non‐ionisée.
Etudes sur les matières végétales volatiles – CXLV. Sur l'iso‐α‐irone et sur les iso‐α‐irols et néo‐iso‐α‐irols
Authors: Naves Yves‐René 
Published: December 2004

AbstractTheiso‐α‐irone (2,6)trans(21,22)cis‐α‐irone) was obtained by fractional distillation of the crude irone prepared by cyclisation of pseudo‐irones by means of boron trifluoride. This ketone and its ethylenic stereoisomer, theneo‐iso‐α‐irone (2,6)trans(21, 22)trans‐α‐irone were reduced to alcohols by means of lithium‐aluminium hydride without noticeable stereomutation.
Über die Alkaloide aus der Rinde von Strychnos melinoniana Baillon. 25. Mitteilung über Calebassen‐Alkaloide
Authors: Bächli E. , Vamvacas C. , Schmid H. , Karrer P. 
Published: December 2004

AbstractAus der Rinde von Strychnos melinoniana Baillon wurden ausser den von E. Schlittler & J. Hohl früher dargestellten Melinoninen A und B 12 weitere Alkaloide isoliert: Melinonine E, F, G, H, I, K, L, M, Mavacurin, Fluorocurin sowie l‐Narcotin und Thebaïn. Die beiden letzteren Pflanzenbasen stammen sehr wahrscheinlich nicht aus der Rinde, sondern sind während deren Aufarbeitung künstlich eingeschleppt worden.
Isolierung und Aufteilung der chloroformlöslichen Bestandteile der chinesischen Krötengiftdroge Ch'an Su. Über Krötengifte, 10. Mitteilung
Authors: Ruckstuhl Jean‐Pierre , Meyer Kuno 
Published: December 2004

AbstractMit Hilfe des chromatographischen Aufteilungsverfahrens an Al2O3 und durch Papierchromatographie liessen sich im Chloroformextrakt eines neuen Handelsmusters von Ch'an Su 11 Bufogenine nachweisen, wovon 10 in reiner Form präparativ herausgearbeitet werden konnten, während das elfte (Substanz B = Desacetyl‐bufotalin) nur auf indirektem Wege (durch Verseifung von Bufotalin) rein erhalten werden konnte. Die einzelnen Bufogenine waren im untersuchten Ch'an‐Su‐Muster in folgenden Mengen enthalten (bezogen auf die rohe Droge): Cinobufagin 4,2–4,5%, Resibufogenin ∥roh) 1,7–2 %, Bufalin 1,25–1,5 %, Cinobufotalin 1,0–1,2 %, Gamabufotalin 0,85 bis 1,0 %, Bufotalin 0,6–0,8 %, Telocinobufagin 0,5–0,6 %, Substanz A = Desacetyl‐cinobufagin 0,3–0,4 %, Substanz C = Hellebrigenin 0,17–0,2 %, Substanz D = Desacetyl‐cinobufotalin 0,12–0, 15 %, Substanz B = Desacetyl‐bufotalin 0,10–0,15 %.
Versuch zur Erklärung des papierchromatographischen Verhaltens von Zuckern
Authors: Jäger Herbert , Ramel A. , Scindler O. 
Published: December 2004

AbstractDie Wanderungsgeschwindigkeit von Zuckern im Papierchromatogramm wird in Beziehung gebracht zu der Konstellation der Hydroxylgruppen in der pyranosiden Form.Die Tatsache, dass Zucker im Papierchromatogramm als einheitliche Substanz wandern, obgleich sie in Lösung in verschiedenen im Gleichgewicht stehenden Formen existieren, wird theoretisch begründet.
Zur quantitativen Beschreibung des Einflusses von Substituenten auf das Absorptionsspektrum ebener Molekeln. Anwendung auf Anthrachinon
Authors: Labhart H. 
Published: December 2004

AbstractEs wird gezeigt, wie man ein System von Parametern finden kann, mit dessen Hilfe es möglich ist, bei Kenntnis der Spektren einiger Derivate einer Grundsubstanz die Absorptionswellenlängen und Intensitäten anderer Derivate mit guter Genauigkeit zu extrapolieren. Bei der Anwendung auf disubstituierte Anthrachinonderivate ergab sich eine Genauigkeit zwischen experimentellem und berechnetem Wert von ± 8μ in der Wellenlänge des langwelligsten π‐Elektronenüberganges. Der Einfluss intramolekularer H‐Brücken auf die Absorption scheint gering. Die Polarisationsrichtung des behandelten Überganges liegt sehr wahrscheinlich parallel der Querachse der Anthrachinonmolekel.
Untersuchungen über den sterischen Verlauf säurekatalysierter Cyclisationen bei terpenoiden Polyenverbindungen. 3. Mitteilung. Zur Stereochemie der Bicyclofarnesylsäuren
Authors: Stadler P. A. , Eschenmoser A. , Schinz H. , Stork G. 
Published: December 2004

AbstractDie Stereochemie der seinerzeit von A. Caliezi & H. Schinz sowie G. Stork & A. W. Burgstahler beschriebenen Bicyclofarnesylsäuren (Smp. bzw. 131°, 138° und 154°) wurde festgelegt. Es handelt sich in diesen Verbindungen um Derivate des trans‐Decalins.
Azeotropismus und Mischungswärme chemisch und physikalisch ähnlicher Verbindungen (Häufigkeit des Azeotropismus durch Kompensation von Beiträgen bei der Dampfdruckdifferenz und Summierung beim Energiebedarf der Vermischung)
Authors: Kuhn Werner , Kuhn H. J. 
Published: December 2004

AbstractDie Siedepunktsdifferenz ΔT von Substanzen, welche einander physikalisch und chemisch ähnlich sind, wird darauf zurückgeführt, dass gewisse für die van der Waal'sche Anziehung der Molekeln wichtige Kenngrössen wie Molekelradien, Polarisierbarkeiten, Dipolmomente usw. für solche Substanzen nahezu, aber nicht ganz dieselben Werte besitzen. Die Unterschiede werden durch für die Unterschiede in den einzelnen Kenngrössen charakteristische Differenzparameter festgehalten.
Über Muscarin. 8. Mitteilung. Herstellung von racemischem Allomuscarin
Authors: Corrodi H. , Hardegger E. , Kögl F. 
Published: December 2004

AbstractDie Nomenklatur für Stereoisomere des Muscarins wird festgelegt. Es werden Reaktionsbedingungen angegeben, die auf dem im Formelschema angedeuteten Weg aus einfachen Estern in guter Ausbeute zu racemischem Allomuscarin führen, obwohl als Zwischenprodukte Gemische diastereomerer Verbindungen auftreten.
Elektronenstruktur und physikalisch‐chemische Eigenschaften von Azo‐Verbindungen Teil V: Über den Einfluss von Substituenten auf das Absorptions‐Spektrum des Phenyl‐azo‐azulens, ein Beitrag zur Kenntnis der PLATTNER'schen Verschiebungsregel
Authors: Gerson F. , Heilbronner E. 
Published: December 2004

AbstractIt is shown that for phenyl‐azo‐azulenes substituted in the benzene nucleusthe position ṼB.Iof the band corresponding to the long‐wave transition depends linearly on the Hammett σxvalue of the substituent Xthe shift ΔṼB.IIof the intense π→π* transition at 24 000 cm−1on protonation of the azo link depends linearly on σx, provided that σx‐ σ′xis negative.
Synthese des Colchicins
Authors: Schreiber J. , Leimgruber W. , Pesaro M. , Schudel P. , Threlfall T. , Eschenmoser A. 
Published: December 2004

AbstractEs wird eine von Purpurogallin, bzw. Pyrogallol ausgehende Totalsynthese des Colchicins, des Hauptalkaloids der Herbstzeitlose, beschrieben.
Stoffwechselprodukte von Actinomyceten. 32. Mitteilung. Über die Konstitution von Nonactin
Authors: Dominguez J. , Dunitz J. D. , Gerlach H. , Prelog V. 
Published: December 2004

AbstractThe neutral, colourless and optically inactive metabolite nonactin, C40H64O12, obtained from cultures of several Actinomyces strains, is a macrocyclic tetralactone (“macrotetrolide”) I of racemic nonactic acid, C10H18O4. The constitution II has been established for the latter by degradation. Crystallographic data for nonactin are reported.
Über die Dünnschichtchromatographie von Lipiden. 1. Mitteilung. Untersuchungen von Gehirngewebe Multiple‐Sklerose‐Kranker und Normaler
Authors: Honegger C. G. 
Published: December 2004

Abstract1. Brain tissue (white and grey matter) of two multiple sclerosis patients and two normals has been extracted with 2:1 chloroform‐methanol.
Aromatische Substitution des Tyrosins bei der sauren Hydrolyse seiner Carbobenzoxyderivate
Authors: Iselin B. 
Published: December 2004

AbstractThe side reactions observed on acid hydrolysis (6 N HCl; 20 hrs at 115°C) of carbobenzoxy derivatives of tyrosine containing peptides were investigated by hydrolyzing carbobenzoxy‐L‐tyrosine or O‐benzyl‐L‐tyrosine under the same conditions or by reacting L‐tyrosine with benzylchloride in the presence of 6N HCl. In every instance the reaction mixture contained besides tyrosine 3 new products distinguishable by paper chromatography. The fractionation of the mixture yielded a mono‐benzylated tyrosine considered to be 3‐benzyl‐L‐tyrosine (I) and two different products which were shown to contain 2–3 benzyl residues in the aromatic ring. These results demonstrate that the benzyl cation formed in the course of the hydrolysis of carbobenzoxy derivatives of tyrosine containing peptides transforms L‐tyrosine into derivatives substituted in the aromatic nucleus.
Konstitution und Reaktionsfähigkeit von Trichlor‐pyrimidylamino‐Verbindungen
Authors: Ackermann H. , Dussy P. 
Published: December 2004

Abstract2,4,5,6‐Tetrachlorpyrimidin wurde mit Ammoniak, aliphatischen und aromatischen Aminen umgesetzt und es konnte gezeigt werden, dass dabei fast ausschliesslich das Chlor in 4‐Stellung des Pyrimidinrings substituiert wird.
Reaktionen von Steroid‐Hypojoditen VI. Substitutionen tertiärer Wasserstoffatome. Über Steroide, 200. Mitteilung
Authors: Heusler K. , Kalvoda J. 
Published: December 2004

AbstractThe attack of an oxy radical (produced by the hypoiodite reaction) on a tertiary hydrogen atom, followed by base treatment, leads to an allylic ether: a 4α‐hydroxy‐5 βH‐steroid gives a Δ‐4α, 9α‐oxide as the main reaction product. It is postulated, that in cases where the initial 1,5‐hydrogen shift from carbon to oxygen leads to a sterically hindered carbon radical, the iodine atom does not combine with the radical. By transfer of an electron from carbon to iodine an ion pair is formed which decomposes by elimination of HI. The final allylic ether is produced by addition of a newly formed oxy radical to this double bond, followed by another oxidation and/or substitution elimination reaction.
Structure et réactions du composé d'addition: triphénylphosphine ‐ anhydride maléique
Authors: Hudson R. F. , Chopard P. A. 
Published: December 2004

AbstractThe structure of the adduct between maleic anhydride and triphenylphosphine has been determined by direct synthesis and spectral analysis. It is analogous to a phosphine methylene derivative (WITTIG reagent) stabilized by an u‐carbonyl group. With aldehydes, it gave none or very poor yields of the expected olefins; water (or alcohols) caused the anhydride ring to open, instead of forming triphenylphosphine oxide plus the corresponding hydrocarbon.
Pyridinderivate als Komplexbildner V. Die Metallkomplexe von 1,10‐Phenanthrolin und α, α′‐Dipyridyl
Authors: Anderegg G. 
Published: December 2004

AbstractThe complex formation of Mg2+, Ca2+, Pb2+, Mn2+, Fe2+, C02+, Ni2+, Cu2+, Zn2+, Cd2+, Hg2+ and Cu+ with l,l0‐Phenanthroline and K, α′‐Dipyridil have been investigated using potentiometric measurements (20°, μ = 0,l (NaNO3)). Since some of these complexes are formed in rather acid solution the usual procedure of pH titration would not be very suitable. For this season displacement reactions have been measured in many cases. The results of these measurements are in good agreement with those obtained using the pHg‐method or redox potential measurements.
Fluoreszenzmethoden zur histochemischen Sichtbarmachung von Monoaminen. 1. Identifizierung der fluoreszierenden Produkte aus Modellversuchen mit 6,7‐Dimethoxyisochinolinderivaten und Formaldehyd
Authors: Corrodi H. , Hillarp N. Å. 
Published: December 2004

AbstractWhen primary or secondary catecholamines are treated with formaldehyde gas in a dried protein layer a strong fluorescence appears which is used for histochemical identification of these amines in central and peripheral adrenergic nerves.
Beiträge zur Chemie der Si‐N‐Bindung, XVIII [1]. Über lineare, cyclodisilazan‐modifizierte Oligosiloxane
Authors: Fink Walter 
Published: December 2004

AbstractLinear oligosiloxanes with cyclodisilazane rings built into the siloxane chain were prepared by the reaction of hydroxysilyl substituted cyclodisilazanes in the form of their lithiumsilanolates with dimethyldichlorosilane, α,ω‐chlorosiloxanes or dimethylchlorosilyl substituted cyclodisilazanes.
Etudes sur les composés organométalliques. X [1]. Action d'organomagnésiens sur la benzophénone
Authors: Dubsky George Jon , Jacot‐Guillarmod André 
Published: December 2004

AbstractVarious Grignard reagents and their diorganomagnesium complexes with ether or pyridine have been reacted with benzophenone, using different mole ratios and orders of addition. Analysis of the reaction products has provided information as to probable reaction mechanisms of addition and reduction. A monomeric diorganomagnesium reagent, favoured either by addition of the reagent to the ketone or by complexation of the reagent with pyridine, enhances if possible the reduction reaction.
Structure of hygromycin B, an antibiotic from Streptomyces hygroscopicus; The use of CMR. spectra in structure determination, I
Authors: Neuss N. , Koch K. F. , Molloy B. B. , Day W. , Huckstep L. L. , Dorman D. E. , Roberts J. D. 
Published: December 2004

AbstractDas Antibioticum Hygromycin B, eine Verbindung C20H37N3O13 aus Streptomyces hygroscopicus, wurde hydrolytisch gespalten und die Spaltprodukte charakterisiert und identifiziert. Die Kenntnis ihrer Struktur und die Interpretation von 13C‐NMR.– (CMR.)‐ Spektren führten zur Strukturaufklärung des Antibiotikums.
Vernetzung von Phenolcarbonsäureestern von Polysacchariden durch oxydative phenolische Kupplung
Authors: Geissmann T. , Neukom H. 
Published: December 2004

AbstractGuaran, a watersoluble polysaccharide, was esterified with various phenolic acids. Solutions of these esters formed gels upon oxidation. In these gels the phenolic ester groups were crosslinked by oxidative phenolic coupling, the corresponding dimeric phenolic acids being liberated by saponification.
Biosynthesis of Betalaines. On the Cleavage of the Aromatic Ring during the Enzymatic Transformation of Dopa into Betalamic Acid
Authors: Fischer Nikolaus , Dreiding André S. 
Published: December 2004

AbstractBei der enzymatischen Umwandlung von 3′,4′‐Dihydroxyphenylalanin (Dopa) in Betalaminsäure, in Betalain‐haltigen Centrospermen, wird der aromatische Ring an der Bindung neben den beiden Hydroxylgruppen (C(4′)‐C(5′)) und nicht zwischen den Hydroxyl gruppen (C(3′)‐C(4′)) gespalten. Dies ergab sich aus dem Einbau von L‐Tyrosin‐[3′,5′‐3H] in Betanin mit Kaktusfruchtmiaterial. Das [3H]‐Betanin und das daraus durch Hydrolyse erhaltene Betanidin enthielten ∼90% des Tritiums am C(11), denn nach Behandlung des Betanins mit Prolin fanden sich ∼90% der Radioaktivität im Indicaxanthin und nur ∼10% im Cyclodopaderivat, und Behandlung des Betanidins mit CF3COOH bewirkte keine Radioaktivitätsverminderung durch 1H‐3H‐Austausch.
Thermochemische Untersuchungen an cyclischen Ketonen
Authors: Wolf G. 
Published: December 2004

AbstractThe enthalpies of formation of the nine cyclic ketones CnH2n−2O (n = 4–12) were determined by combustion calorimetry. The heats of vaporization were determined by measuring the vapor pressure as a function of temperature and the heats of fusion of the three compounds with n = 8, 9, 12 which are solids at room temperature, by DSC.
Isolierung von (2S, 4S)‐(+)‐γ‐Hydroxynorvalin und (2S, 4R)‐(−)‐γ‐Hydroxynorvalin aus Boletus satanas Lenz
Authors: Matzinger P. , Catalfomo Ph. , Eugster C. H. 
Published: December 2004

AbstractWe have isolated from the carpophores of Boletus satanas Lenz (Basidiomycetae) (2S,4S)‐(+)‐γ‐hydroxynorvaline (1) and (2S,4R)‐(−)‐γ‐hydroxynorvaline (2). The chirality of each diastereomer has been determined by chemical synthesis starting from optically active precursors and by application of different chiroptical methods. Gaschromatographic separation of the derived diastereomeric N‐[(S)‐α‐methoxypropionyl]‐lactones reveals that the optical purity of natural 2 is 88% whereas 1 exists as a partial racemate: (2S,4S): (2R,4R) = 3:2.Muscarine could not be detected in the carpophores of B. satanas, contrary to some literature data but basic substances of unknown structure are present in low concentration.
Farbstoffsensibilisierte Photoreaktionen von vinylogen Epoxycarbonylverbindungen
Authors: Skorianetz Werner , Ohloff Günther 
Published: December 2004

AbstractOn irradiation in the presence of dye sensitizers, vinylogous epoxy carbonyl compounds undergo a novel photofragmentation reaction, to give furyl ketones in good yields. The fragmentation process is probably preceded by trans‐cis isomerization of the double bond; in one case the cis‐isomer could be isolated. In a side reaction epoxyenone 10 gives the cyclopentanone derivatives 13 and 14 by a [1, 2] shift of a methyl group.Similar dye sensitized photolysis of the endo‐peroxide 2 also gives the corresponding furyl ketone 4, and the corresponding vinylogous epoxyketone C is probably an intermediate in this transformation.The finding that dyes of relatively low triplet energies (∼ 30 kcal/mol) efficiently sensitize these reactions, and a certain wave length dependence suggest that the usual triplet mechanism cannot be involved.
Zur Kenntnis von Rifamycin‐S. Reaktionen des chinoiden Nucleus. Modifikationen von Antibiotica, 9. Mitteilung [1]
Authors: Kump Wilhelm , Bickel Hans 
Published: December 2004

AbstractThe reactivity of rifamycin‐S (1) with respect to nucleophilic reagents has been studied. Several new classes of derivatives, some of which show interesting biological activities, are described.
Organic Phosphorus Compounds. Part 64 synthesis of 4,6‐dimethylamino‐2‐cyclohexyl‐2H‐1,3,5,2‐Pv‐thiadiazaphosphorin‐2‐thione
Authors: Maier Ludwig 
Published: December 2004

AbstractIn the reaction of cyclohexylmonothiophosphonic anhydride, [C6H11P(S)O]3, with dimethylcyanamide not the expected 2H‐1,3,5,2‐Pv‐thiadiazaphosphorin‐2‐oxide derivative is formed, but the corresponding thione derivative, the title compound, is obtained.
Zur Kontrolle von Solid‐phase Peptidsynthesen durch Eluat‐Chloridbestimmung
Authors: Fankhauser Peter , Fries Peter , Brenner Max 
Published: December 2004

AbstractThe origin of chloride ion in chloroform and methylene chloride solutions of tertiary amines is studied. The applicability of such solutions in the analytical control of solid phase peptide synthesis must be seriously questioned. An alternative procedure, amenable to automation, is suggested.
Absolute Konfiguration der enantiomeren α‐CyclogeraniumsäUren, α‐Cyclogeraniale, α‐Jonone, γ‐Jonone, α‐und ϵ‐Carotine
Authors: Buchecker Richard , Egli Robert , Regel‐Wild Helen , Tscharner Christoph , Eugster Conrad Hans , Uhde Gerald , Ohloff Günther 
Published: December 2004

AbstractBy chemical correlation with manool and ambrein the absolute configurations of the enantiomeric α‐cyclogeranic acids, α‐cyclogeranials, α‐ionones and α‐ and ϵ‐carotenes have been elucidated.
Quinazolines et benzodiazépines‐1,4. LX Imidazo[5,1‐c]benzodiazépines‐1,4
Authors: Jaunin Roland , Arnold Wolf 
Published: December 2004

AbstractUpon treatment with oxalyl chloride followed by reaction with the appropriate nucleophile, the 3‐carbamoyl‐benzodiazepines 6, 7 and 8 were converted stereospecifically to the tricyclic compounds 12, 13, 14, 16 and 19. Epimerization of 19 in presence of p‐toluenesulfonic acid led to 21. The stereochemistry of these tricyclic compounds and of some of their N(2)‐alkyl derivatives (22‐31) has been established by NMR. spectroscopy. Under proper reaction conditions, attack by bases on the tricyclic esters 13 and 26 was shown to cause an inversion of the chiral center C(11a) and to yield stereospecifically rearranged products, e.g. 23 from 26 and 33 from 13.
The Reaction of Singlet Oxygen with α‐ and β‐Pinenes
Authors: Jefford Charles W. , Boschung André F. , Moriarty Robert M. , Rimbault Christian G. , Laffer Mostyn H. 
Published: December 2004

AbstractThe reaction of photogenerated singlet oxygen with α‐ and β‐pinenes has been carefully re‐examined. α‐Pinene almost exclusively (99.3% yield) furnishes trans‐3‐hydroperoxy‐pin2(10)‐ene. However, detectable amounts of the three other possible products are also found, viz., cis‐3‐hydroperoxypin‐2 (10)‐ene (˜0.8%), and cis‐ and trans‐2‐hydroperoxypin‐3 (4)‐ene (˜0.04%). β‐Pinene gives 99.9% of 10‐hydroperoxypin‐2 (3)‐ene and a trace (˜0.01%) of norpinan‐2‐one. Rates of reaction and product composition are treated by modal analysis and reflect the operation of steric and stereoelectronic factors in a reactant‐like transition state.
Thermochemical Kinetics of Nitrogen Compounds. Part 4. The gas phase unimolecular thermal decomposition of triallylamine
Authors: Vitins Peter , Egger Kurt W. 
Published: December 2004

AbstractThe gas phase thermal decomposition of triallylamine was studied in the temperature range 531 to 620 K. The major products observed in the reaction were propylene and 3‐picoline. The first order rate constants for depletion of triallylamine, obtained using the internal standard technique, are found to be independent of pressure and conversion, and fit the Arrheniusrelationship

The reaction appears to be homogeneous, as a 15‐fold change in thc surface‐to‐volume ratio of the vessel left the rate constants unchanged. The Arrhenius parameters are consistent with a molecular elimination reaction involving a six‐center transition state, yielding propylene and N‐allyl‐prop‐2‐enaldimine. It is proposed that the latter product undergoes a 1,5‐hydrogen transfer, followed by a ring closure reaction to yield dihydropicoline, which in turn reacts forming 3‐picoline via a self‐initiated decomposition reaction.
Alkylierung der 3‐Acyl‐thio‐ und ‐dithio‐carbazinester‐Gruppierung CONHNHCSYR
Authors: Rüfenacht Kurt 
Published: December 2004

Abstract3‐Benzoyl‐thiocarbazic acid O‐methyl ester 7a and 3‐benzoyl‐dithiocarbazic acid methyl ester 7b are methylated, in presence of alkali, at the SH group of 1a, the ene‐thiol tautomer of 1, to give the 3‐benzoyl‐isothiocarbazic acid O, S‐dimethyl ester 8a and the 3‐benzoyl‐isodithiocarbazic acid dimethyl ester 8b resp., which clearly differ from the N‐methylated compounds 11a and 12a or 11b and 12b prepared from the two N‐methyl benzohydrazides 9 and 10 resp. (melting points, thin‐layer chromatography and NMR. spectra).The previously reported [1] ring closure of 3‐(ω‐chloroalkanoyl)‐thiocarbazic acid O‐alkyl esters and ‐dithiocarbazic acid alkyl esters can be interpretated as an intramolecular auto‐alkylation of CONHNHCSYR: the 3‐(chloroacetyl)‐compounds 2 are S‐alkylated (enethiol form) to the six‐membered thiadiazinones 4, but the 3‐(3‐chloropropionyl)‐compounds 3 are N‐alkylated to the pyrazolidinones 6, the five‐membered ring being preferred in the latter case to the seven‐membered ring 5 which would be formed by S‐alkylation. Hence the position of alkylating attack depends on the size of the ring to be formed.As a consequence, starting from 3‐(4‐chlorobutyryl) compounds 13, an alternative between the two N‐alkylation products 14 (five‐membered ring) and 15 (six‐membered ring) would be expected. On the contrary however, a combination of 1,3,4‐thiadiazole ring closure and chlorine elimination predominates, giving the 5‐(3‐hydroxypropyl)‐1,3,4‐thiadiazoles 16. This reaction may proceed via the butyrolactone intermediates 18 and could therefore be interpreted as O‐alkylation followed by rearrangement.