Reactions of Disulfides Derived from Penicillin Sulfoxides with Tertiary Phosphines in Presence of Carboxylic Acids

A novel method for the preparation of thioesters starting from Iso-Fujisawa disulfides is reported. The presence of an acylamino group cis to the disulfide function on the β-lactam nucleus seems to be an essential requirement for this reaction. In the absence of such a cis-acylamino group, desulfurization, is the preferred course.     

Star-like discotic liquid crystals

The game of molecular engineering of liquid crystalline systems via a combination of molecular architecture and functionalization of mesogens has opened interesting perspectives in the field of liquid crystals. Here we report on the synthesis and characterization of star-like heptameric triphenylenes. The discotic subunits in these molecules have been arranged in a hexagonal fashion around a central discotic core, thus leading to a new type of molecular arrangement for discotic liquid crystals. These oligomers do not crystallize and combine a well-defined structure with a discotic polymer-like processing.     

Zur Verbindungsbildung von MeO:M2O3. VI. Darstellung und Strukturaufklärung von Sr1,33 Pb0,67 Al6O11

Compound Formation MeO: M₂O₃. VI. Synthesis and Structure Determination of Sr_1,33 Pb_0,67 Al₆O₁₁ Single crystal of Sr_1,33Pb_0.67Al₆O₁₁ could be prepared with a PbO flux. (Space group D–Pnnm, a = 22.13, b = 4.88, c = 8.42 Å, Z = 4) Sr²⁺ and Pb²⁺ are statistically intercalated into a framework of AlO₆ octahedra and AlO₄ tetrahedra. The typical coordination of Sr²⁺ and Pb²⁺ is realized by occupying different positions in the same cavern.