α-Alkoxy-β-dicarbonylverbindungen durch Acylierung von Lithiumenolaten

A series of -alkoxy--dicarbonyl compounds2 were prepared by acylation of lithium enolates in good to excellent yields by a simple one-pot procedure.

     

Synthese von α-Methyl-homocysteinthiolacton

Summary A facile high yield large scale methylation procedure affording2c is reported utilizing the N-[bis(methylthio)-methylen-protected derivative4a as an intermediate. The optical resolution of racemic2c is described leading to (S)-2b. In addition the thiolactone2c undergoes oxidative ring opening by bromine to the corresponding sulphonic acid5.

     

Darstellung und Eigenschaften von 2-Acyl-1,2-thiazetidin-1,1-dioxiden

Title compounds3a–3i were synthesized by acylation of 1,2-thiazetidine 1,1-dioxide by various methods. Spectroscopic data elucidate the conformation and geometry of the fourmembered ring. An X-ray analysis of3i is presented.

     

Bestimmung der Aktivitätskoeffizienten im chromatographischen Modell „binärer Lösungen“

An explanation is given for the two possible ways of determination of the activity coefficients of solutes, when applying a new thermodynamic model of adsorption and partition chromatography, i. e. the binary solutions model.

     

N-Arylsulfonyl-N′-pyrimidinylsubstituierte Chloralaminale

N-Arylsulfonyl-N-pyrimidinyl substituted aminals of chloral were prepared from N-(1-Hydroxy-2,2,2-trichloroethyl)arylsulfonamides with thionyl chloride and subsequent reaction with aminopyrimidines.

     

Tetracyclische Imidazole

2-(Phenacyl)-tetrahydro--carboline (2) was transformed to theE/Z-oximes3 and4 and the isolated species cyclodehydrogenated to the nitrone5 and oxadiazine6. These compounds were dehydrated in acidic medium to the imidazole9.

     

Discontinuous flow-through measurement of gamma-rays. Principles of operation and application in clinical biochemistry

Ohne Zusammenfassung

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Discontinuous flow-through measurement of gamma-rays. Principles of operation and application in clinical biochemistry

     

O-Heterocycles by the cyclization of side-chain bromomethoxylated 2′-acetoxychalcones

Summary The title chalcone derivatives react with aqueous sodium hydroxide of various concentrations to form aurones as the major product, together with small amounts of flavones. However, the introduction of 4-nitro or 4-chloro substituents resulted in the formation of flavones as the major product.

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O-Heterocyclen mittels Cyclisierung von an der Seitenkette brommethoxylierten 2-Acetoxychalconen

Zusammenfassung Die im Titel genannten Chalconderivate reagieren mit Natronlauge in verschiedenen Konzentrationen, wobei Aurone zusammen mit geringen Mengen an Flavonen entstehen. Die Einführung von 4-Nitro- oder 4-Chlor-Substituenten führte jedoch zur bevorzugten Bildung von Flavonen.

     

Konformationen diastereoisomererBis-(alkylaryl)-ether

Summary X-ray-analysis of the meso-ether2 showed the existence of two bridged species in the unit cell besides the expected molecule. The additional bonds between the 9- and 10-positions of the anthracene moieties were extraordinarily long. This fact leads to conclusions on the reactive behaviour of alkylaryl carbinoles upon acid-catalysed etherification.

     

N-(2,6-Dihalobenzoyl)-N′-pyrimidinylharnstoffe

N-(2,6-Dichlorobenzoyl)- and N-(2,6-difluorobenzoyl)-N-pyrimidinylureas3b–3n have been synthesized by reaction of the corresponding aminopyrimidine derivatives with 2,6-dichlorobenzoyl isocyanate or 2,6-difluorobenzoyl isocyanate. The insecticidal activity of compounds3b–3n has been evaluated.

     

Charge-transfer complexes betweenp-toluidine and iodine in solution: A kinetic study

The kinetics of charge-transfer interaction betweenp-toluidine and iodine in methylene chloride was investigated in depth. Thethermal process of formation of theinner complex was found to proceed to an equilibrium. Thephotochemical process follows a different reaction coordinate, going through the formation of an exciplex between the excitedouter complex and the amine ground state. In both cases the same ionic complex (Am ₂I⁺I ₃ ^– , whereAm stands forp-toluidine) was detected as the final product.

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Kinetische Untersuchung der Charge-Transfer-Komplexe zwischenp-Toluidin und Jod

Zusammenfassung Die Kinetik der Charge-Transfer-Wechselwirkung zwischenp-Toluidin und Jod in Methylenchlorid wurde ausführlich untersucht. Derthermische Prozeß, der zur Bildung desinner-Komplexes führt, geht bis zu einem Gleichgewicht. Derphotochemische Prozeß folgt einer unterschiedlichen Reaktionskoordinate und verläuft über die Bildung eines Exziplexes zwischen dem angeregtenouter-Komplex und dem Amin im Grundzustand. In beiden Fällen wurde derselbe ionische Komplex (Am ₂I⁺I ₃ ^– , wobeiAm fürp-Toluidin steht) als Endprodukt festgestellt.

     

Substituierte 3-Amino-thiophene und 3-Amino-selenophene aus β-Chlor-α-cyan-zimtsäurenitril

Summary -Chloro--cyano-cinnamonitrile (1) reacts in one step with -oxo-thioles3 or successively with sodium sulphide and -chlorocarbonyl compounds4 to form the 5-substituted 4-amino-2-phenyl-thiophene-3-carbonitriles5. Analogously, the successive reactions of -chloro cinnamonitrile1 with sodium selenide — produced in situ from selene and sodium boronhydride — and -chlorocarbonyl compounds4 yields the 5-substituted 4-amino-2-phenyl-selenophene-3-carbonitriles6.

     

Synthesis of pyridine derivatives by reactions of α,β-unsaturated nitriles with 2-oxo-cycloalkano carbothioic acid anilides

Summary The tandem Michael addition-cyclization of 2-oxo-cycloalkane carbothioic acid anilides1–3 to benzylidenemalononitrile4 yielded spiroannulated pyridines5–7. Reaction of acrylonitrile with2 and3 gave 2,2-disubstituted Michael adducts14,15, whereas with1 led to 2,2,5-tri(2-cyanoethyl)-cyclopentanone11.

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Synthese von Pyridinderivaten durch Reaktionen von ,-ungesättigten Nitrilen mit 2-Oxo-cycloalkano-thiokohlensäure-aniliden

Zusammenfassung Die Michael Tandem-Addition-Cyclisierung von 2-Oxo-cycloalkano-thiokohlensäure-aniliden1–3 mit Benzylidenmalononitril4 ergab die spiroannelierten Pyridine5–7. Reaktion von Acrylnitril mit2 und3 ergab die 2,2-disubstituierten Michael-Addukte14,15, wohingegen mit1 2,2,5-Tri(2-cyanethyl)-cyclopentanon11 erhalten wurde.

     

Fungizide Pyridinderivate, 4. Mitt.: α-Trifluormethyl-3-pyridinmethanole

Summary The synthesis of a series of the title compounds is described applying the addition of 3-pyridyllithium to appropriate trifluoromethylalkanones (path 1) and addition of lithiumorganyls to 2,2,2-trifluoro-1-(3-pyridyl)-ethanone (path 2), respectively.

     

Amino- und Hydroxylaminosubstituierte α-Azidozimtsäureester und α-Aminozimtsäureester durch kathodische Reduktion ungesättigter Nitroazidoester

Cathodic reduction of nitro-substituted azidocinnamic esters on mercury under aprotic and protic conditions was studied. Nitro and azido groups behave as independent entities so that selectively amino- resp. hydroxylamino--azido compounds are obtained, which could not be synthesised by conventional methods. Under aprotic conditions, with added acetic anhydride, medium yields of acylated 4-hydroxylamino- and 4-amino--cinnamic acid derivatives are isolated. Evidence of homogeneous electron transfer from nitroanion radicals to azido groups is given.

     

Eine Bemerkung zur Berechnung des Diamagnetismus in der Xα-Theorie

Zusammenfassung Ein Lagrange-Formalismus für die X-Theorie wird diskutiert und in diesem Zusammenhang eine Formel für die Berechnung der diamagnetischen Suszeptibilität erhalten.

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A remark on the calculation of the diamagnetism in the X-theory

A Lagrange formalism for the X-theory is discussed. In this connexion a formula for the calculation of the diamagnetic susceptibility is obtained.

     

Spektroskopische Untersuchungen an organischen Carbonylverbindungen, 5. Mitt.: Zum Einfluß des π-Chromophors auf das elektronische Spektralverhalten von dimethylaminophenyl-substituierten β-Diketonen bei Kettenverlängerung und Variation der Arylsubstituenten

Summary Absorption and fluorescence data of dimethylaminophenyl-substituted -dicarbonyl compounds are discussed in dependence on the size of the -electronic system. The variation of the chain length and of the aryl moiety shows the strong influence of the intramolecular donor-acceptor properties on the deactivation processes. The stabilization of the S₁-state in polar solvents gives rise to fluorescences with large Stokes shifts.

     

Reactions with β-cyanoethylhydrazine,III. A new approach for the synthesis of substituted 3,5-diaminopyrazole and 1,2,4-triazoles

The reactivity of -cyanoethylhydrazine toward enaminonitrile and aroyl isothiocyanates is reported. A variety of 3,5-diaminopyrazole and ³-1,2,4-triazolin-5-thione derivatives could be prepared.

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Reaktionen mit -Canyethylhydrazin, 3. Mitt.: Ein neuer Weg zur Synthese von substituierten 3,5-Diaminopyrazolen und 1,2,4-Triazolen

Zusammenfassung Es wird über die Reaktivität von -Cyanethylhydrazin gegenüber Enaminonitril und Aroylisothiocyanaten berichtet. Es konnte eine Reihe von 3,5-Diaminopyrazol-und ³-1,2,4-Triazolin-Derivaten hergestellt werden.