Cationic starch ethers have been established as additives in the paper industry for many years. A number of production processes are known and documented in numerous patents and articles. Whereas in the past starches were predominantly etherified in aqueous suspension, a trend has lately been observed towards a “dry” cationisation. Apart from the commercial aspects, the advantages of a “dry” reaction control lie in the ecological sphere as well. The advantages of the dry process for producing cationic starch ethers will be discussed here and compared with the “slurry” process. In so doing, particular attention will be paid to a dry process developed by our company since it is gaining nowadays more and more commercial relevance.

Skin regeneration is a quite complex process. Epidermal differentiation alone takes about 30 days and is highly regulated. Wounds, especially chronic wounds, affect 2% to 3% of the elderly population and comprise a heterogeneous group of diseases. The prevailing reasons to develop skin wounds include venous and/or arterial circulatory disorders, diabetes, or constant pressure to the skin (decubitus). The hallmarks of modern wound treatment include debridement of dead tissue, disinfection, wound dressings that keep the wound moist but still allow air exchange, and compression bandages. Despite all these efforts there is still a huge treatment resistance and wounds will not heal. This calls for new and more efficient treatment options in combination with novel biocompatible skin scaffolds. Cold atmospheric pressure plasma (CAP) is such an innovative addition to the treatment armamentarium. In one CAP application, antimicrobial effects, wound acidification, enhanced microcirculations and cell stimulation can be achieved. It is evident that CAP treatment, in combination with novel bioengineered, biocompatible and biodegradable electrospun scaffolds, has the potential of fostering wound healing by promoting remodeling and epithelialization along such temporarily applied skin replacement scaffolds.

Addition of Diazacyclopropanes to Carbonyl CompoundsDiazocyclopropanes (6,38, 57) were generated in equilibrium with cyclopropanediazonium ions by base-induced cleavage of the analogous nitrosoureas in methanol. Efficient trapping of the diazocyclopropanes occurred in dilute solution with a slight excess of carbonyl compounds. The reactivity of the resulting l-(u-hydroxyalky1)cyclopropanediazonium ions (10) depended strongly on the a-substituents. Pinacol rearrangements predominated with aldehyde adducts, the migratory aptitudes being H > Ph > CH3. These 1,2-shifts are thought to proceed with inversion at the terminus -the preferred exo-attack of acetaldehyde at 7-diazonorcarane (38) led to the endo-ketone 40. The major product derived from the acetone adduct 22 was the epoxide 26 whose reaction@) with methanol were also examined. The intramolecular addition of 8-diazobicyclo[5.1 .O]octan-4-one (57) gave rise to 6-methoxybicyclo[3.3.0]oct-4-en-l-ol (60). Due to steric constraints, the intermediate 58 underwent exclusive cyclopropyl-ally1 transformations (otherwise a minor reaction).Umsetzungen von Diazoakanen mit Carbonylverbindungen gehoren zum Standard-Repertoire der praparativen organischen Chemie und sind mechanistisch gut untersucht'). Auch Diazocyclopropan wurde gelegentlich zur Ringerweiterung cyclischer Ketone eingesetzt'-". Wir liel3en einfache Carbonylverbindungen auf Di-

The diazocyclo compound (I), which is obtained from the corresponding nitrosourea, equilibrates with the diazonium salt and adds to carbonyl compounds such as (II) in CH3OH to form adducts of type (III).

were separated and configurationally assigned by iodolactonization of the syn isomer. Nitrous acid deaminations of the amines 16-19 were performed in aqueous lithium bromide solutions. Thus, the intervening carbocations were trapped to give stable tricyclic bromides 23-26 as the major products. Predominant retention of configuration was observed with all substrates although the syn-amine 17 deviated significantly from its anti isomer 16 and from the higher homologs. Charge delocalization in the tricyclic cation 31 appears to be enhanced relative to the bicyclo[3.1 .O]hex-3-yl cation (3).