Einflu? des Reaktionsmediums auf die Kinetik und den Mechanismus der kationischen Polymerisation und Copolymerisation der cyclischen ?ther

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Conjugative and homoconjugative effects in 2-heterobicyclo[3.2.1]octa-3,6-dienes

The ¹H-NMR, ¹³C-NMR and photoelectron spectra of a variety of 2-heterobicyclo[3.2.1]octa-3,6-dienes 6 give evidence of conjugative and homoeonjugative effects in these compounds, but there is no suggestion from the data of any special contribution from the (4n+2)π neutral bishomoaromatic system. Reaction of the dienes6 with TCNE invariably yielded the product of [2+2] addition in cases where a fully characterisable product was obtained.     

Polyimidazopyrrolone model compounds

The model reactions between phthalic anhydride and o-phenylenediamine were studied under conditions analogous to the polymerization and post cyclization of dianhydrides with bis(o-diamines) to form polyimidazopyrrolones (Pyrrones). The route from the initial amide-acid-amine to the tetracyclic Pyrrone model when the reactions are conducted in aprotic solvents is highly competitive between isolatable benzimidazole-acid and imide-amine intermediates. Solid-state thermal conversion of the amide-acid-amine affords a unique dimeric species containing amide, imide, and benzimidazole functions. It was confirmed that melt techniques lead to disproportionation products. The application of these findings to related polymer synthesis is discussed.     

Theoretische Untersuchung des Prozesses der Bildung von Kondensationspolymeren — Polvamidsäuren

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Untersuchung der enzymatisch aktiven Trypsin-fragmente

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Detection and determination of N-nitrosamines by thin-layer chromatography using fluorescamine.

A novel procedure is described for the detection and determination of N-nitrosamines (NAs) on thin-layer chromatographic plates. Ultraviolet irradiation of NAs on activated plates (silica gel or aluminum oxide) yields primary or secondary amines, which after spraying with fluorescamine reagent give fluorescent or non-fluorescent products, respectively. The majority of the 24 NAs examined afforded NAs, although the volatile dimethyl-, diethyl- and pyrrolidine-N-nitrosamines gave limits of 500, 40, and 40 ng, respectively. Spectrophotometric determinations of the relative fluorescence of 0.1-40 nmoles of NAs gave rise to nearly linear calibration curves when plotted on a log-log scale.     

Uniform approximation: The non-locally convex case

IfS is a compact Hausdorff space of finite covering dimension and (E, τ) is a real or complex topological vector space (not necessarily locally convex), we prove a Weierstrass-Stone theorem for subsets ofC(S;E), the space of all continuous functions fromS intoE, equipped with the topology of uniform convergence overS.