Zur Bestimmung der Kohlens?ure

Ohne Zusammenfassung     

Preparation of Neutral Ionophores for Alkali and Alkaline Earth Metal Cations and their application in ion selective membrane electrodes

The preparation of a series of non-cyclic, uncharged ligands able to selectively complex alkali and alkaline earth metal cations is described. These molecules are designed to be used as carriers for cations through membranes. Some of the compounds show high Ca²⁺ and Na⁺ selectivity, respectively, in liquid membrane electrodes.     

Über die Darstellung und die Eigenschaften des Indo-oxins

Zusammenfassung Es wird eine Darstellungsmethode für das vonBerg undBecker beschriebene Indo-oxin angegeben. Für das Produkt werden die Absorptionsspektren in verschiedenen Lösungsmitteln mitgeteilt. Die Darstellung des bisher unbekannten Hydrochlorids wird beschrieben.Mit 2 Abbildungen.Meinem verehrten Lehrer, Herrn Professor Dr.A. Franke, zum 80. Geburtstag gewidmet.W. P.     

Use of Dimethylsilyl Ethers for Characterizing Primary Aliphatic Alcohols: A comparison of mass spectrometric fragmentation of di- and trimethylsilyl derivatives

Mass spectral fragmentation patterns of dimethylsilyl (DMS) ethers of primary unbranched, branched, and secondary unbranched aliphatic alcohols in the C₅ to C₁₀ range are compared with those of the corresponding trimethylsilyl (TMS) derivatives. Unlike their TMS analogues, DMS ethers of primary alcohols exhibit pronounced rupture of the C? C bond adjacent to the oxygen atom within the alkyl moiety (loss of an alkyl radical R) in marked preference to cleavage within the silyl substituent (loss of CH₃). Within this class of compounds, complementary preparation of DMS derivatives can therefore be used to establish or to confirm the site, and thus the primary nature of the hydroxyl group, whereas preparation of TMS ethers may be of advantage in deducing molecular size. For the derivatives of secondary alcohols this diagnostically useful difference in fragmentation behaviour is not observed.     

Einsatz von Hochleistungs-Trennkapillaren in der GC.-EIMS./GC.-CIMS.-Analyse: Eine Möglichkeit zur massenspektrometrischen Doppelbindungscharakterisierung in komplexen Monoalkengemischen

In an attempt to determine position and substitution of double bonds in complex mixtures of straight-chain and branched monoalkenes without actually isolating the constituents, GC.-MS. analysis is performed after in-batch preparation of derivatives of a judiciously chosen type. Cyclic phenylboronates (4,5-substituted 2-phenyl-1,3,2-dioxaborols) are prepared from 1,2-diols which are, in turn, obtained from the original alkenes by treatment with osmium tetroxide. Chemical ionization mass spectrometry (CIMS.) is used in addition to conventional electron impact techniques (EIMS.) in sequential GC./CIMS.- and GC./EIMS.runs, yielding complementary structural information for the single components of the mixture. In order to cope with the potential severity of the separation problem, high-efficiency glass capillary columns were employed throughout. The performance of the system used is demonstrated by a complete double bond analysis of a 35-component mixture of monoalkenes in the C₅ to C₉ range.     

Synthese und Abbau von 1-(5-Nitro-2-thiazolyl)-2-imidazolidinon und Derivaten

1-(5-Nitro-2-thiazolyl)-2-imidazolidinone is synthesized from 2-amino-5-nitro-thiazole and 2-chloroethyl-isocyanate. The structure of this new potent schistosomicide is established by acid and alkaline degradation as well as by synthesis starting from 2-imidazolidinone. A number of derivatives of 1-(5-nitro-2-thiazolyl)-2-imidazolidinone are reported.     

On the aromaticity of annulenones

Application of our method of predicting aromaticity¹ shows that the behavior of the annulenones is intermediate between that of the fulvenes (a nonaromatic series) and the annulenes (a series with strong alternation between aromatic and antiaromatic).