Synthesis of iodobiaryls and dibenzofurans by direct coupling at BDD anodes.

The first direct oxidative phenol-arene cross-coupling reactions of an iodine-containing guaiacol derivative and the possible over-oxidation products of electron-rich phenols are described. Hereby, a "green" and targeted synthesis for dibenzofurans was developed.

Allylated cyclodextrins as effective affinity materials in chemical sensing of volatile aromatic hydrocarbons using an optical planar Bragg grating sensor.

We report on the application of perallyl-substituted α-, ß- and γ-cyclodextrins to an optical planar Bragg grating refractive index sensor for the effective sensitization of the sensor for airborne volatile aromatic hydrocarbons. Thereby, the emphasis of this work lies on the comparison of the different cyclodextrin types regarding their suitability as affinity material assessed by the sensors sensitivity and response behavior. The opto-chemical sensor device showed an immediate and quick response to the application of the investigated analytes benzene, toluene and m-xylene as well as a linear dependence on the concentration of those analytes. Studies on the sensors sensitivity depending on the applied cyclodextrin types revealed a generally higher sensitivity for the sensor sensitized with perallyl-substituted ß-cyclodextrins. Here, the sensor systems detection limit was found to 60±4 ppm for benzene, 18±3 ppm for toluene and 3.8±0.5 ppm for m-xylene. The response time and recovery time were found to approximately 30s and 40s, respectively, depending on the applied cyclodextrin and the chosen analyte.

Structural revision and synthesis of altechromone A.

The chromone "altechromone A" was synthesized as a substructure in the course of natural product synthesis. Its architecture was verified by X-ray analysis, but spectroscopic data showed a strong deviation from the reported data. By comparison with the synthesized isomers the structure of altechromone A was revised.