Cyclopeptid-Antibiotika aus Aspergillus-Arten. Struktur der Echinocandine C und D

Cyclopeptide antibiotics from Aspergillus species. Structure of echinocandins C and D The echinocandins B, C and D are antifungal antibiotics produced by a strain of Aspergillus rugulosus. All three metabolites are closely related representing cyclic oligopeptides composed of six amino acids and a linolic acid residue in an amide linkage. The complete structure of echinocandin B ( 1 ) has recently been established by X-ray analysis. Structural assignments to the new minor metabolites C and D have now been made by hydrolytic and oxidative cleavage reactions, formation of N-acyl-α-aminoethers as well as by chemical correlations and extensive NMR. examinations. Echinocandin C ( 2 ), C₅₂H₈₁N₇O₁₅, contains 3-hydroxyhomotyrosine in the place of 3, 4-dihydroxyhomotyrosine present in 1 . Echinocandin D ( 3 ), C₅₂H₈₁N₇O₁₃, differs in two amino acids: 3, 4-dihyroxyhomotyrosine and 4, 5-dihydroxyornithine, unusual units of 1 being replaced by 3-hydroxyhomotyrosine and ornithine.     

Gas-liquid chromatographic method for the measurement of plasma levels of d-7,8-dimethoxy-3-methyl-phenyl-2,3,4,5-tetrahydro-1h-3-benzazepine acid maleate (SCH-12679) and its major metabolites in aggressive mental retardites

A sensitive gas-liquid chromatographic technique for the quantitative analysis of SCH-12679 (d-7,8-dimethoxy-3-methyl-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine acid maleate) and its major metabolites in plasma of aggressive mental retardates receiving therapeutic doses of the medicament has been developed. The lower limits of detection are 20 ng/ml for SCH-12679, 0.5 ng/ml for 3-desmethyl SCH-12679 and 0.4 ng/ml for 7-desmethyl plus 8-desmethyl SCH-12679. SCH-12679 is estimated with a flame ionization detector. Its metabolites are quantitated using an electron-capture detector after conversion of the compounds to their heptafluorobutyryl derivatives by reaction with the appropriate anhydride. Data on plasma levels of unchanged SCH-12679, 3-desmethyl SCH-12679 and a combination of 7-desmethyl and 8-desmethyl SCH-12679 in fifteen patients treated with the medicament are presented.     

PHYTOCHROME MEDIATION OF UREDOSPORE GERMINATION IN THE FUNGUS PUCCINIA GRAMINIS

Abstract—Applying criteria used for higher plants, phytochrome mediation of uredospore germination in the stem-rust fungus, Puccinia graminis f. sp. tritici (Eriks & Henn) Guyot is established. A 1 min red irradiation at 660 nm promotes uredospore germination and this potentiation of promotion is photoreversible by a 1 min far-red irradiation at 730 nm.     

The synthesis of possible hydroxylated metabolites of 2-chlorophenothiazine derivatives

The synthesis of 7-hydroxy, 8-hydroxy and 7,8-dihydroxy prochlorperazines (3a) and per-phenazines (3b) is reported. The parent ehlorophenothiazines were prepared analogously to previously reported chlorpromazine (3e) metabolite syntheses. The prochlorperazine side chain was introduced in one step using 1-(3-chloropropyl)-4-methylpiperazine and the perphenazine side chain in two steps, first reaction with 1-bromo-3-chloropropane followed by reaction with 1-piperazineethanol. The methoxymethyleneoxy O-proteetive groups were removed under mild conditions using methanolic hydrogen chloride. The preparations of 7-hydroxydesmethylprochlorperazine and 7-hydroxychlorpromazine quaternary methyl iodide are also reported.     

Contribution à l'étude du comportement de la catéchine en milieu alcalin

Contribution to the study of the behaviour of catechin in alkaline medium When catechin ( 1 ) is warmed with aqueous alkali it first undergoes rapid epimerisation. After some time a novel bridged carbocyclic enol, catechinic acid ( 3 ) separates out and may be isolated in excellent yield. Eventually catechinic acid isomerises to 2-(3′,4′-dihydroxyphenyl)-3,9-epoxy-6-oxo-bicyclo[3,3,1]-non-7-en-8,9-diol ( 4 ) via an open chain anion ( 5 ) which is also involved in the epimerisation of catechin. Assignments of structure are given and the equilibria observed are discussed.     

Analyse synthetischer Flugturbinen?le durch Gas-Chromatographie-Massenspektrometrie

Zusammenfassung Ein handelsübliches synthetisches Flugturbinenöl auf Basis von Fettsäuretriestern des Trimethylolpropans und Fettsäurehexaestern des Dipentaerythrits wurde mittels GC-MS untersucht. Die Bildung der für die Analytik beider Polyolester wichtigen Ionen bei der elektronenstoßinduzierten Fragmentierung wird diskutiert. Die komplexen Estergemische konnten gas-chromatographisch nach der Molmasse der Esterkomponenten getrennt werden. Die Auftrennung isomerer Trimethylolpropanester gelang nicht. Ihre Identifizierung war aber massenspektrometrisch möglich.Die Struktur der als Nebenkomponenten vorliegenden Fettsäurehexaester des Dipentaerythrits konnte ebenfalls massenspektrometrisch geklärt werden. Die Bestimmung der quantitativen Fettsäurezusammensetzung des Trimethylolpropanester und Dipentaerythritesteranteils nach säulenchromatographischer Trennung und Berechnung der möglichen Esterkomponenten erlaubten eine detaillierte Charakterisierung dieses komplexen Systems.

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Analysis of synthetic aviation turbine oils by gas chromatography-mass spectrometry.Part II. trimethylolpropane ester/dipentaerythritol ester oils

Summary A commercial synthetic aviation turbine oil based on fatty acid triesters of trimethylolpropane and hexaesters of dipentaerythritol was investigated by gems. The formation of specific ions by electron impact induced fragmentation which are important for the analysis of these oils is discussed. The complex ester mixtures can be separated by gas chromatography according to molecular size of the ester components. The separation of isomeric trimethylolpropane esters is not successful.The identification of these components is possible by mass spectrometry. The structure of the minor components present, fatty acid hexaesters of dipentaerythritol, was also determined by mass spectrometry. The determination of quantitative fatty acid composition of the trimethylolpropane ester and dipentaerythritol ester components after separation by column chromatography and calculation of the possible ester components allowed a detailed characterisation of the complex ester system present.