A large number of diversely functionalized analogs of the bioactive natural products neocryptolepine and isocryptolepine have been prepared from a series of 3-bromoquinoline derivatives. The neocryptolepines were obtained by a Pd0-catalyzed C−C bond coupling followed by C−N bond formation in yields up to 80 %, whereas the indoloquinolines were prepared by a Suzuki-Miyaura cross-coupling followed by azidation-photochemical cyclization in yields ranging from traces to 95 % yield. 相似文献
Electrostatic self‐assembly can be used to form supramolecular vesicles in aqueous solution. Vesicles consist of cationic G8 poly(amidoamine) dendrimers and the trivalent sulfonate dye Ar27. No classical amphiphiles are present but the interplay of electrostatics, π–π interaction and geometric factors influences the structure formation. Labeled guest molecules, both small molecules and peptides, can be included inside these vesicles and vesicles imaged by fluorescence techniques. The structure was studied by dynamic and static light scattering, small‐angle neutron scattering, confocal laser scanning microscopy, and fluorescence correlation spectroscopy. The study indicates the prospect of constructing functional nanoobjects by the self‐assembly of charged molecules in aqueous solution.
Abyssomicin C and its atropisomer are potent inhibitors of bacterial folate metabolism. They possess complex polycyclic structures, and their biosynthesis has been shown to involve several unusual enzymatic transformations. Using a combination of synthesis and in vitro assays we reveal that AbyV, a cytochrome P450 enzyme from the aby gene cluster, catalyses a key late-stage epoxidation required for the installation of the characteristic ether-bridged core of abyssomicin C. The X-ray crystal structure of AbyV has been determined, which in combination with molecular dynamics simulations provides a structural framework for our functional data. This work demonstrates the power of combining selective carbon-13 labelling with NMR spectroscopy as a sensitive tool to interrogate enzyme-catalysed reactions in vitro with no need for purification. 相似文献