About the selectivity and reactivity of active nickel electrodes in C-C coupling reactions.

Active anodes which are operating in highly stable protic media such as 1,1,1,3,3,3-hexafluoroisopropanol are rare. Nickel forms, within this unique solvent, a non-sacrificial active anode at constant current conditions, which is superior to the reported powerful molybdenum system. The reactivity for dehydrogenative coupling reactions of this novel active anode increases when the electrolyte is not stirred during electrolysis. Besides the aryl-aryl coupling, a dehydrogenative arylation reaction of benzylic nitriles was found while stirring the mixture providing quick access to synthetically useful building blocks.

Surface conditioning with cold argon plasma and its effect on the osseointegration of dental implants in miniature pigs.

PURPOSE: Successful implant therapy is based on fast, safe, and predictable osseointegration. Several surface modifications have been introduced to improve the bone-to-implant interaction. This in vivo study evaluates the impact of plasma surface conditioning on early wound healing and osseointegration. MATERIALS AND METHODS: A total of 16 dental implants with a sand-blasted and acid-etched surface were conditioned with cold atmospheric plasma prior to insertion in the frontal bone of four miniature pigs. Sequential fluorescence labeling was administered to label bone metabolism, and after 8 weeks, bone blocks were harvested for radiological, histological, and histomorphometrical evaluation. RESULTS: The plasma conditioning had no impact on the morphology of the implant surface. The bone-to-implant contact ratio was 90.4% and 86.5%, the interthread bone density 72.5% and 63.4%, and the periimplant bone density 60.5% and 61.1%, in the plasma conditioned group and control group, respectively. Concentric bands of fluorescence enrichment indicated a chronological and homogenous mineralization of newly formed bone. No unwanted periimplant side effects were detected. CONCLUSION: The increased parameters for osseointegration in this in vivo study merit further investigation in prospective clinical trials.

Reagent- and Metal-Free Anodic C-C Cross-Coupling of Aniline Derivatives.

The dehydrogenative cross-coupling of aniline derivatives to 2,2'-diaminobiaryls is reported. The oxidation is carried out electrochemically, which avoids the use of metals and reagents. A large variety of biphenyldiamines were thus prepared. The best results were obtained when glassy carbon was used as the anode material. The electrosynthetic reaction is easily performed in an undivided cell at slightly elevated temperature. In addition, common amine protecting groups based on carboxylic acids were employed that can be selectively removed under mild conditions after the cross-coupling, which provides quick and efficient access to important building blocks featuring free amine moieties.