Papierchromatographische Trennungen von Alkaloidgemischen an Succinylzellulose-Papieren

Zusammenfassung Das früher beschriebene¹ Succinylzellulose-Papier wird als Ionenaustauscher zur weiteren papierchromatischen Trennung von Basengemischen verwendet. Getrennt wurden die Alkaloide der Morphingruppe und deren Abwandlungsprodukte, ferner die Alkaloide der Strychnin-, der Tropin-, der Cocaingruppe und andere Alkaloide.

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Summary The succinyl-cellulose paper described previously¹ is used as ion exchanger for additional paper chromatographic separations of mixtures of bases. Separations were accomplished of the alkaloids of the morphine group and their modification products, and also of the alkaloids of the strychnine-, tropine- and cocaine groups and other alkaloids.

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Résumé On utilise le papier à la succinyl-cellulose déjà décrit¹, comme écharigeur d'ions pour d'autres séparations par chromatographie sur papier de mélanges basiques. On a séparé ainsi les alcaloïdes du groupe de la morphine et leurs produits d'évolution, et en outre, les alcaloïdes des groupes de la strychnine, de la tropine et de la cocaïne et d'autres alcaloïdes.

     

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.     

Komplexometrische Bestimmung von Metallkationenverunreinigungen in Reinchemikalien

Zusammenfassung Ein Verfahren zur quantitativen summarischen Bestimmung von Metallionenverunreinigungen in flüssigen Chemikalien (Reinheitsprüfung) durch komplexometrische Titration mit photometrischer Endpunktsanzeige wird beschrieben. Als Indikator dient Eriochromschwarz T; erfaßbar ist zirka 1 g in 20 ml. Durch einfaches Einengen des Ausgangsmaterials lassen sich noch Metallionengehalte von 0,01 ppm mit einer Genauigkeit von einigen Prozent bestimmen.

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Summary A procedure is described for the quantitative summary determination of metal ion impurities in liquid chemicals (purity tests) through complexo-metric titration with photometric endpoint indication. Eriochrome black T serves as indicator. Approximately 1 g can be detected in 20 ml. Metal ion contents as low as 0.01 ppm can still be determined with a precision of several per cent by simple concentration of the starting material.

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Résumé On décrit un procédé de dosage total quantitatif des impuretés à l'état d'ions métalliques dans les produits chimiques liquides (contrôle de la pureté) par titrage complexométrique avec détection du point équivalent par photométrie. On utilise le noir ériochrome T comme indicateur. La limite de dilution est d'environ 1 g/20 ml. On peut encore doser des teneurs en ions métalliques de 0,01 ppm avec une erreur de quelques pour cent simplement en diminuant la quantité initiale de substance.

     

Photochemistry of Bacteriochlorophylls in Human Blood Plasma: 1. Pigment Stability and Light-induced Modifications of Lipoproteins

Transmetalated derivatives of bacteriochlorophyll are promising sensitizers in photodynamic therapy. Protocols using short delay times between injection and irradiation cause interest in the photochemistry of these pigments in the blood. Using near-infrared irradiation where these pigments absorb strongly, we have studied the photochemistry of Zn- and Pd-bacteriopheophorbide (WST09), and of the highly polar taurinated Pd-derivative, WST11, in isolated fractions of human blood plasma. The stability of all pigments is increased in blood plasma, compared with monomeric solutions. Pd-bacteriopheophorbide is much more stable than the other two derivatives. It also has a higher capacity for inducing reactive oxygen species, yet the consumption of oxygen is comparable. There is furthermore evidence for photobleaching under anoxic conditions. The generation of hydroperoxides (ROOH) is faster with Pd- than with Zn-complexes; the formation of endoperoxides (ROOR′), measured as thiobarbituric acid reactive substances, is comparable with the two central metals. Formation of both ROOH and ROOR′ is increased in low-density lipoproteins (LDL) compared with high-density lipoproteins (HDL), which is probably related to the higher concentration of target molecules in the former. In HDL, extensive cross-linking is induced among the apolipoproteins; judged from the electrophoretic mobility of LDL and HDL particles, there is also a gross structural change. Photosensitized cross-linking is much less pronounced with high-density proteins.     

Die chemie der schweren carben-analogen R2M,M = Si,Ge, Sn: IX. Eigenschaften und thermolyse von neuen 7-silabicyclo[2.2.1]heptadienen

Factors governing the ease and mechanism of 7-silabicyclo[2.2.1]heptadienes thermolysis in order to generate free silylenes and the corresponding benzene derivatives are investigated. For this purpose, 29 new compounds of the types VII–X have been prepared. No indications for a polar mechanism or an intermediate biradical could be found. The degradation is exactly of first order in all cases investigated sofar, and is enhanced by phenyl groups at the bridgehead C atoms, if a conformation coplanar with the basic ring is allowed by the neighbouring substituents, but is not enhanced by phenyl groups at the Si. The X-ray structure of two typical derivatives is discussed with this respect. A special mechanism is operating in the easy thermolysis of carbomethoxy-substituted compounds leading to cyclic sila enolether intermediates.     

Reaction of Anthranilamide with Phosphorus Pentasulfide: Formation of 2-Mercapto-(1H)-1,3,2λ5-benzodiazaphosphorine-2,4-dithione

The reaction of anthranilamide with phosphorus pentasulfide in boiling pyridine leads to the benzodiazaphosphorine-pyridine salt 2 . The structure is established by elemental analysis, ¹H- ¹³C- ¹⁵N- ³¹P-NMR, and mass spectral data.     

Caloric properties of dilute nonelectrolyte solutions: A success story

Selected aspects of the thermodynamics of very dilute solutions of gases in liquids, in particular aqueous solutions, are reviewed and connected with recent high-precision experimental techniques [vapor-liquid equilibrium measurements (VLE), calorimetry and densimetry]. Some of the problems encountered in data reduction and data correlation over large temperature ranges, including the critical region, are discussed. The focus is on caloric properties, such as partial molar enthalpy changes on solution, ΔH^∞₂, and partial molar heat capacity changes on solution, ΔC^∞_P,2: direct calorimetric methods are compared with indirect methods based on VLE studies as a function of temperature (van't Hoff approach).