Regio-controlled hydrogen-deuterium exchange of biologically important indoles under uv irradiation

Photochemical hydrogen-deuterium exchange reaction of biologically important indoles is reported. The regioselectivity of the photodeuteration was found to be controlled by the ammonium group of the side chain.     

Vinylpolymerisation. 281. Mitt

Ohne Zusammenfassung     

Potassium ion-selective membrane electrodes based on naphtho-15-crown-5

The potassium-selective PVC membrane electrodes based on naphtho-15-crown-5 have rapid, stable and Nernstian response in the range 10^-1–10^-5 M. The selectivity coefficient for potassium over sodium is 4 × 10^-4.     

Studies directed toward the total synthesis of the rubradirin antibiotics. 4. A new Diels-Alder—Claisen effective diene

A new diene has been synthesized which effectively couples the Diels-Alder reaction with the Claisen rearrangement.     

Synthesis of functionalized asymmetric star polymers containing conductive polyacetylene segments by living anionic polymerization

Novel 3-arm ABC, 4-arm ABCD, and 5-arm ABCDE asymmetric star polymers comprising the conductive polyacetylene precursor, poly(4-methylphenyl vinyl sulfoxide) (PMePVSO), and other segments, such as polystyrene, poly(alpha-methylstyrene), poly(4-methoxystyrene), poly(4-trimethylsilylstyrene), and poly(4-methylstyrene), were synthesized by the methodology based on living anionic polymerization using DPE-functionalized polymers. This methodology involves the addition reaction of a DPE-functionalized polymer to a living anionic polymer followed by the living anionic polymerization of MePVSO initiated from the in situ formed polymer anion with two, three, or four polymer segments. The resultant asymmetric star polymers possessed predetermined molecular weights, narrow molecular weight distributions (Mw/Mn < 1.03), and desired compositions as confirmed by SEC, 1H NMR, SLS, and elemental analysis. After thermal treatment, the PMePVSO segment in the star polymer could be completely converted into a conductive polyacetylene segment, evident from TGA and elemental analysis. These asymmetric star polymers are expected to exhibit interesting solution properties and unique microphase-separated morphological suprastructures with potential applications in nanoscopic conductive materials. Moreover, this methodology can afford the target asymmetric star polymers with arm segments varying in a wide range and enables the synthesis of more complex macromolecular architectures.