Use of a highly effective intramolecular Pauson-Khand cyclisation for the formal total synthesis of (±)-α- and β-cedrene by preparation of cedrone

The cedrene carbon skeleton was directly and efficiently assembled from a simple monocyclic precursor by the strategic use of a high yielding intramolecular Pauson-Khand cyclisation reaction. A small number of further synthetic manipulations provided a concise formal total synthesis of α- and β-cedrene. The cyclisation precursor was readily prepared, with a stereoselective ketone alkenylation selectively providing the olefin required for efficient access to the natural target.     

Immunologic relatedness of extracellular ligninases from the actinomycetesstreptomyces viridosporus t7a andstreptomyces badius 252

Four isoforms of the extracellular lignin peroxidase of the ligninolytic actinomyceteStreptomyces viridosporus T7A (ALip-P1, P2, P3, and P4) were individually purified by ultrafiltration and ammonium sulfate precipitation, followed by electro-elution using polyacrylamide gel electrophoresis. Three of the purified peroxidases were compared for their immunologic relatedness by Western blot analysis using a polyclonal antibody preparation produced in rabbits against pure isoform P3. The anti-P3 antibody was also tested for its reactivity towards a lignin peroxidase from the white-rot fungusPhanerochaete chrysosporium and another ligninolytic actinomyceteStreptomyces badius 252. Results showed that peroxidases ALip-P1 through ALip-P3 are immunologically related to one another. The peroxidases ofS. badius, but not the peroxidase ofP. chrysosporium, also reacted with the antibody, thus indicating that the lignin peroxidases ofS. viridosporus andS. badius are immunologically related. Based upon its specific affinity, lignin peroxidase isoform ALip-P3 ofS. viridosporus was readily purified using an anti-P3 antibody affinity column.     

The direct determination of organic oxygen in coals

Summary A method is described for the determination of the organic oxygen content of coals,Interfering mineral matter is removed by treatment with dilute hydrochloric acid under specified conditions, after which the resulting extracted sample is dried under controlled non-oxidising conditions.From this prepared sample, a weighed portion is introduced into a specially designed apparatus in which it is pyrolysed under rigidly controlled conditions of heating in the presence of an inert carrier gas, The oxygenated products of pyrolysis are then, with the carrier gas, passed over a platinised carbon catalyst by means of which the oxygen compounds are reduced to carbon monoxide.Finally, the carbon monoxide produced is allowed to react with heated iodine pentoxide, and the resulting iodine is determined by the Leipert titration procedure. The oxygen content of the original sample is calculated after certain corrections have been applied.

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Zusammenfassung Eine Methode zur Bestimmung des organisch gebundenen Sauerstoffs in Kohle wurde beschrieben.Störendes anorganisches Material wird durch Behandlung mit verd. Salzsäure unter besonderen Bedingungen entfernt. Die extrahierte Probe wird dann unter Ausschluß oxydierender Einflüsse getrocknet.Eine Einwaage davon wird in einer eigens dafür bestimmten Apparatur bei streng eingehaltener Temperatur in Gegenwart eines inerten Trägergases pyrolysiert. Die sauerstoffhältigen Pyrolyseprodukte gelangen mit dem Trägergas über platinierte Kohle, wo sie zu Kohlenmonoxyd reduziert werden. Dieses reagiert schließlich mit erhitztem Jodpentoxyd. Das freigesetzte Jod wird nachLeipert titriert. Bei Berechnung des Sauerstoffgehaltes der ursprünglichen Probe sind bestimmte Korrekturen anzubringen.

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Résumé On décrit une méthode de dosage de l'oxygène organique contenu dans les charbons.On élimine la matière minérale gênante par traitement à l'acide chlorhydrique dilué dans des conditions données, après quoi l'on sèche l'échantillon extrait sous des conditions contrôlées non oxydantes.On introduit un poids donné de cet échantillon dans un appareil construit spécialement dans lequel on le soumet à une pyrolyse sous des conditions strictement contrôlées de chauffage en présence d'un gaz inerte entraîneur. On fait alors passer les produits oxygénés de la pyrolyse, avec le gaz entraîneur, sur un catalyseur au charbon platinisé, grâce auquel les composés oxygénés sont réduits en oxyde de carbone.Finalement, on fait réagir l'oxyde de carbone produit, avec l'anhydride iodique chauffé et l'on dose l'iode résultant suivant le procédé de titrage deLeipert. On calcule la teneur en oxygène de l'échantillon original après avoir appliqué certaines corrections.