Ueber die Untersuchung von Balsamen und Harzen

Ohne Zusammenfassung     

Reduction von schwefliger S?ure zu Schwefelwasserstoff

Ohne ZusammenfassungBrünn am 2. April 1897.     

Formeln zur Berechnung bei indirecten Analysen

Ohne Zusammenfassung     

Synthesis of 6-[[(hydroxyimino)phenyl]methyl]-1-[(1-methylethyl)sulfonyl]-1H-imidazo[4,5-b]pyridin-2-amine. An aza analogue of enviroxime

6-[[(Hydroxyimino)phenyl]methyl]-1-[(1-methylethyl)sulfonyl]-1H-imidazo[4,5-b]pyridin-2-amine ( 1 ), an aza analogue of enviroxime, was synthesized in eight steps from 6-hydroxynicotinic acid ( 2 ). Acid 2 was nitrated, chlorinated with phosphorus pentachloride, and subjected to Friedel-Crafts aroylation to give 6-chloro-5-nitro-3-pyridyl phenyl ketone ( 5 ). Amination of 5 was followed by reduction of the nitro group and condensation with ethoxycarbonylisothiocyanate to give 6-benzyl-2-ethoxycarbonylamino-1H-imidazo[4,5-d]pyridine ( 8 ). The ethoxycarbonyl moiety of 8 was cleaved, N-1 was isopropylsulfonylated, and the carbonyl moiety was condensed with hydroxylamine to give 1 . Compound 1 was inactive against rhinovirus 1B and poliovirus type 1 .     

Impact of filter paper on fluorescence measurements of buffered saline filtrates

Fluorescent contaminants have been observed when stock solutions of phosphate buffered saline solutions at each of three pH values (2.2, 7.5, and 12.5) are analyzed after passing through commercially available filter paper. The filtrate's fluorescence was observed to exhibit a maximum signal at 440.0 nm when excited at 365 nm. Detection of trace components could have significant implications in the design and implementation of sample processing protocols when using fluorescence.     

Mechanisms of catalytic biomass gasification

This paper discusses possible mechanisms for the pyrolytic reaction of biomass with steam in the presence of alkali carbonate and supported-nickel catalysts. In addition to catalyzing the carbon/steam reaction, the alkali carbonates alter the biomass pyrolysis reaction path-ways, producing gas and char at the expense of tars. Nickel catalyst, while quite effective for secondary tar and gas reactions, tend to lose activity over time; therefore, studies of these catalysts were directed toward identifying mechanisms of carbon deposition, the primary cause of catalyst deactivation.     

A5–4 PYRIMIDINE-PYRIMIDONE PHOTOPRODUCT PRODUCED FROM MIXTURES OF THYMINE AND 4-THIOURIDINE IRRADIATED WITH 334 nm LIGHT

The nucleoside 4-thiouridine, present in some bacterial tRNA species, is known to be a chromophore and a target for near-UV light-induced growth delay and also mediates both photoprotection and near-UV cell killing in various bacterial strains. To investigate the photoreaction of 4-thiouridine with DNA or its precursors, we irradiated aqueous mixtures of thymine and 4-thiouridine with 334 nm light and then separated photoproducts using two or more stages of reversed-phase high performance liquid chromatography. The two equally abundant major photoproducts were analyzed by UV absorbance spectrophotometry, fast-atom bombardment and electron-impact mass spectrometry, and ¹H- and ¹³C-NMR spectroscopy, and have been identified as two diastereomers of 6-hydroxy-5-[1-(β-D-erythro-pentofuranosyl)-4′-pyrimidin-2′-one]dihydrothymine (o⁶hThy[5-4]Pdo), of molecular weight = 370.32. These two diastereomers, although stable at room temperature or below, are interconvertible by heating (90d?C for 5 min) in aqueous solution. The possible biological significance of this photoproduct is discussed, and an application as a crosslinker for oligonucleotides to selectively block replication is suggested.     

Synthesis of bis(arylsuh'onyl)furoxans from aryl nitromethyl sulfones

The synthesis of some symmetrically substituted bis(arylsulfonyl)furoxans from aryl nitromethyl sulfones is reported.