A novel positively charged nanofiltration membrane has been prepared by the reaction of carboxylic acids on the surface of a polyamide thin film composite with poly(amidoamine) dendrimer in the presence of 2-chloro-1-methylpyridinium iodide as an activating agent. The membrane was prepared with excellent grafting efficiency and showed a high isoelectric point of pH 9.9. Because of the high density of free protonated amino groups, the membrane showed excellent rejections toward various toxic elements including Cu2+, Ni2+ and Pb2+. The rejection order also followed the size of the ions in terms of their hydrated radius. Furthermore, the membrane obtained by the surface grafting method exhibited outstanding alkaline stability compared to the membrane prepared by the conventional coating process. These results clearly indicate that grafting the poly(amidoamine) dendrimer onto the surface of the polyamide thin film composite membrane is a promising approach to improve the rejection of toxic containments.Keywords: Nanofiltration membrane; Poly(amidoamine) dendrimer; Positive charge; Surface grafting; Toxic element removal;

The sequential use of a hypervalent iodine reagent leads to the one-pot synthesis of 2-bromo/chloro-phenanthridinones via an amidation of arenes followed by a regioselective halogenation reaction. These consecutive C–H functionalization reactions can be used efficiently to construct 2-substituted-phenanthridinones at room temperature with good to high yields. Application of the current method is highlighted by the concise synthesis of the natural product PJ34.

•A one-step transformation from free (NH) indoles to 2-arylindole derivatives.•Using norbornene as a transient directing group mediator.•This reaction is compatible with a wide range of functionalized aryl iodides and various substituents on indole.A palladium-catalyzed direct C2-arylation reaction of free (NH) indoles has been developed. This reaction relies on a norbornene-mediated CH activation process on the indole ring, which features high regioselectivity and excellent functional group tolerance.Download high-res image (58KB)Download full-size image

A method for Pd-catalyzed, aminoquinoline-directed arylation of vinylic C–H bonds with aryl iodides has been developed. This reaction represents a rare example of Pd-catalyzed vinylic C–H functionalization of unsubstituted acrylamide, allowing for the highly regio- and stereoselective preparation of Z-olefins. High tolerance to functional groups is observed with good yields and excellent selectivity. It offers a complementary synthetic method to traditional pathways for Z-olefins.

A direct C-2 methylation reaction of indoles bearing a readily removable N-2-pyrimidyl moiety as a site-specific directing group has been developed with a palladium catalyst. This reaction relied on the use of KF to promote efficient methylation. A moderate to good yield was achieved in a range of indole substrates.

•Regioselective homocoupling of indoles via C–H activation was developed.•Thirteen examples of 2,2′-biindoles were synthesized in good to excellent yields.•Biindoles are key synthetic precursors of bioactive indolocarbazoles.A Cu-mediated regioselective, dehydrogenative homocoupling of indoles was developed using AgNO3 as the additive. The easily installed and removed N-pyrimidyl group exerted complete C2 regiocontrol via C–H activation. A series of indole substrates underwent cross-dehydrogenative-homocoupling. This work developed an effective approach for the synthesis of 2,2′-biindole core of a number of chemicals fundamentally important in material and pharmaceutical chemistry.

Cu-mediated C-2 chlorination of indoles was accomplished with copper(II) chloride through the use of a directing pyrimidyl protection group. A highly regioselective manner can be achieved on a range of indole substrates with excellent functional group tolerance.

We report a ligand-free copper-catalyzed Goldberg coupling of a spirocyclic lactam with an aryl iodide or bromide to provide an N-aryl spirocyclic lactam in good to excellent yields. The protocol is applicable to a broad diversity of spirocyclic lactams. The corresponding products can be used for the preparation of tetra- and pent-cyclic compounds 4–7 as potential therapeutic agents in the treatment of diffuse large B-cell lymphoma (DLBCL) and triple negative breast cancer (TNBC).Figure optionsDownload full-size imageDownload as PowerPoint slide

The sequential use of a hypervalent iodine reagent leads to the one-pot synthesis of 2-bromo/chloro-phenanthridinones via an amidation of arenes followed by a regioselective halogenation reaction. These consecutive C–H functionalization reactions can be used efficiently to construct 2-substituted-phenanthridinones at room temperature with good to high yields. Application of the current method is highlighted by the concise synthesis of the natural product PJ34.

A direct C-2 methylation reaction of indoles bearing a readily removable N-2-pyrimidyl moiety as a site-specific directing group has been developed with a palladium catalyst. This reaction relied on the use of KF to promote efficient methylation. A moderate to good yield was achieved in a range of indole substrates.

Cu-mediated C-2 chlorination of indoles was accomplished with copper(II) chloride through the use of a directing pyrimidyl protection group. A highly regioselective manner can be achieved on a range of indole substrates with excellent functional group tolerance.

A method for Pd-catalyzed, aminoquinoline-directed arylation of vinylic C–H bonds with aryl iodides has been developed. This reaction represents a rare example of Pd-catalyzed vinylic C–H functionalization of unsubstituted acrylamide, allowing for the highly regio- and stereoselective preparation of Z-olefins. High tolerance to functional groups is observed with good yields and excellent selectivity. It offers a complementary synthetic method to traditional pathways for Z-olefins.