In vitro and in vivo antifungal profile of a novel and long acting inhaled azole, PC945, on Aspergillus fumigatus infection

The profile of PC945, a novel triazole antifungal, designed for administration via inhalation, hasbeen assessed in a range of in vitro and in vivo studies. PC945 was characterized as a potent, tight-binding inhibitor of Aspergillus fumigatus sterol 14α-demethylase (CYP51A and CYP51B)activity.In addition, when A. fumigatus hyphae or human bronchial cells were treated with PC945, and thenwashed, PC945 was found to be quickly absorbed into both target and non-target cells and toproduce persistent antifungal effects. In temporarily neutropenic immunocompromised miceinfected with A. fumigatus intranasally, 50% of the animals survived until day 7 when treatedintranasally with PC945 at 0.56 μg/mouse, while posaconazole showed similar effects (44%) at14 μg/mouse. This profile affirms that topical treatment with PC945 should provide potentantifungal activity in the lung

On the electronic impact of abnormal C4-bonding in N-heterocyclic carbene complexes

Sterically similar palladium dicarbene complexes have been synthesized that comprise permethylated dicarbene ligands which bind the metal center either in a normal coordination mode via C2 or abnormally via C4. Due to the strong structural analogy of the complexes, differences in reactivity patterns may be attributed to the distinct electronic impact of normal versus abnormal carbene bonding, while stereoelectronic effects are negligible. Unique reactivity patterns have been identified for the abnormal carbene complexes, specifically upon reaction with Lewis acids and in oxidative addition-reductive elimination sequences. These reactivities as well as analytical investigations using X-ray diffraction and X-ray photoelectron spectros-copy indicate that the C4 bonding mode increases the electron density at the metal center substantially, classifying such C4-bound carbene ligands amongst the most basic neutral donors known thus far. A direct application of this enhanced electron density at the metal center is demonstrated by the catalytic