Poly(arylene ether)s with Pendent 3‑Iodophenyl Sulfonyl Groups: Synthesis, Characterization, and Modification

A series of poly­(arylene ether)­s carrying truly pendent functional groups were prepared by the <i>meta</i> activated nucleophilic aromatic substitution (NAS) polycondensation reaction of a new aryl difluoride monomer, 3,5-difluoro-1-((3-iodophenyl)­sulfonyl)­benzene, followed by Suzuki–Miyaura and Heck cross-coupling reactions. The synthesis of 3,5-difluoro-1-((3-iodophenyl)­sulfonyl)­benzene was achieved via the one-step reaction of 3,5-difluorodiphenyl sulfone with <i>N</i>-iodosuccinimide. Model reactions and NMR data indicated that the carbon–iodine functionality was stable to NAS conditions, thus allowing the synthesis of the desired iodo functional poly­(arylene ether sulfone), I-PAES. The iodo moiety was then subjected to palladium-catalyzed cross-coupling reactions with phenyl, naphthyl, and 4-acetylphenyl boronic acids as well as styrene in order to prepare the corresponding phenyl, naphthyl, 4-acetyl phenyl, and 2-phenylvinyl analogues. The polymers were characterized via NMR spectroscopy, size exclusion chromatography, thermogravimetric analysis, and differential scanning calorimetry. The polymers exhibited moderate thermal stability in air, with 5% weight loss temperatures ranging from 404 to 482 °C, while the glass transition temperatures ranged from 131 to 165 °C

Isolation and Characterization of Cyclic C₃₃ Botryococcenes and a Trimethylsqualene Isomer from <i>Botryococcus braunii</i> Race B

Three cyclic C₃₃ botryococcenes and one new trimethylsqualene isomer were isolated from the B race, Showa (Berkeley) strain of <i>Botryococcus braunii</i>, which is known to produce large amounts of isoprenoid hydrocarbons ranging in carbon number from 30 to 34. Their purity was determined by GC-MS, and structures were characterized by 1D and 2D NMR. One of these molecules, cyclic C₃₃-1 botryococcene (<b>5</b>), has an unusual connection of a methylenecyclohexane ring to the molecule backbone not seen before in botryococcenes. This report further adds to our knowledge of the wide range of isoprenoid hydrocarbon structures produced by <i>B. braunii</i>