The Copey tree (Clusia rosea) has a large distribution in Cuba and its floral resin is a rich source of polyisoprenylated benzophenones. To determine the presence of these natural products, we carried out a study by HPLC of 21 propolis samples produced by honey bees (Apis mellifera) from different provinces of Cuba. Nemorosone resulted to be the most abundant polyisoprenylated benzophenone and the mixture of xanthochymol and guttiferone E was also observed, but in minor proportion. We studied the biological activity of the pure natural product nemorosone and its methyl derivatives. We found that nemorosone has cytotoxic activity against epitheloid carcinoma (HeLa), epidermoid carcinoma (Hep-2), prostate cancer (PC-3) and central nervous system cancer (U251). It also exhibited antioxidant capacity. Methylated nemorosone exhibited less biological activity than the natural product

Synthesis of processable, aromatic pyridine-containing polymers has always been a great challenge. Here, we report for the first time a robust, low-cost synthesis of well defined, high molecular weight, linear, wholly aromatic polymers with rigid ether-bond-free aryl backbones, where the proportion and position of pyridine moieties and spacer lengths between them in the macromolecules are fully controlled. The polymers, in nearly quantitative yields, were obtained by one-pot, room temperature, metal-free, non-stoichiometric superacid catalyzed step-polymerization of 4-acetylpyridine (and its mixtures with 2,2,2-trifluoroacetophenone) with multiring aromatic hydrocarbons: biphenyl, meta- and para-terphenyl, and para-quaterphenyl, in the mixture of trifluoromethanesulfonic acid with methylene chloride and trifluoroacetic acid. The polymers are highly soluble in most common solvents and form flexible and tough films with tensile strength in the range of 72–92 MPa. ¹H and ¹³C NMR analyses of the synthesized polymers revealed high regio-selectivity of the polymer forming reaction affording linear structures with para-substitution in the phenylene fragments of the main chains. The molecular weights of the polymers ranged from 20 000 to 100 000 g mol⁻¹, whereas the polydispersity is generally well below 2. The polymers exhibited also high thermostability with T_g > 400 °C, weight loss temperatures (N₂, onset) ca. 485 °C, char yields of 70–75 at 800 °C and high chemical stability. Room temperature reactions of the polymers with methyl(trifluoromethylsulfonate) afford the N-methylated cationic polymers. Certain studies on the physical properties and gas separation of the polymers are highlighted.