We report and analyze the static and dynamic wetting properties of mixed alkanethiols self-assembled monolayers on gold substrates. These were prepared using end-methylated (undecyl mercaptan) and end-hydroxylated (11-mercapto-1-undecanol) compounds of the same length to avoid physical roughness of the resulting monolayer. The characterization of the surface composition was achieved by X-ray photoelectron spectroscopy measurement, showing that the surface composition is statistically not different from the composition of the grafting solution. The critical surface tension γc varies linearly within the range 20.3−39.3 mN/m as the hydroxylation of the surface increases. Contact angle hysteresis is maximum on the 50% hydroxylated surface. The relaxation of the shape of a squalane drop to its equilibrium configuration is well described by the molecular-kinetic theory of wetting, attesting that the energy dissipation during the spreading phenomenon is mainly controlled by the friction of the liquid molecules on the solid substrate. Versus the fraction of methylated/hydroxylated compounds on the surface, we observe a wetting transition for squalane. Below this wetting transition, the friction coefficient ζ between the squalane and the substrate is a linear combination of the friction coefficients measured on the corresponding pure substrates; above the wetting transition, the friction remains quasi-constant.

Bisbenzamidines, such as pentamidine isethionate, are aromatic dicationic compounds that are active against Pneumocystis and other microbes but are oftentimes toxic to the host. To identify potential antiPneumocystis agents, we synthesized bisbenzamidine derivatives in which the parent compound pentamidine was modified by a 1,4-piperazinediyl, alkanediamide, or 1,3-phenylenediamide moiety as the central linker. Several of the compounds were more active against P. carinii and less toxic than pentamidine in cytotoxicity assays. For this study, we evaluated nine bisbenzamidine derivatives representing a range of in vitro activities, from highly active to inactive, for the treatment of pneumocystosis in an immunosuppressed mouse model. Six of these in vitro-active compounds, 01, 02, 04, 06, 100, and 101, exhibited marked efficacies against infection at a dose of 10 mg/kg of body weight, and four compounds, 01, 04, 100, and 101, showed significant increases in survival versus that of untreated infected control mice. Compound 100 was highly efficacious against the infection at 20 mg/kg and 40 mg/kg, with >1,000-fold reductions in burden, and resulted in improved survival curves versus those for pentamidine-treated mice (at the same doses). All six bisbenzamidine compounds that exhibited high in vitro activity significantly decreased the infection in vivo; two compounds, 12 and 102, with marked to moderate in vitro activities had slight or no activity in vivo, while compound 31 was inactive in vitro and was also inactive in vivo. Thus, the selection of highly active compounds from in vitro cytotoxicity assays was predictive of activity in the mouse model of Pneumocystis pneumonia. We conclude that a number of these bisbenzamidine compounds, especially compound 100, may show promise as new anti-Pneumocystis drugs.

Domestic microwave ovens as well as laboratory reactors have been successfully employed to prepare dialkyl 1,4-dihydropyridine-3,5-dicarboxylates and to induce the synthesis of the corresponding aromatic derivatives. In that latter particular case, unexpected results have been reported.