Catalytic Enantioselective Access to Dihydroquinoxalinones via Formal α-Halo Acyl Halide Synthon in One Pot

An enantioselective one-pot catalytic strategy to dihydroquinoxalinones, featuring novel 1-phenylsulfonyl-1-cyano enantioenriched epoxides as masked α-halo acyl halide synthons, followed by a domino ring-opening cyclization (DROC), is documented. A popular quinine-derived urea served as the catalyst in two out of the three steps performed in the same solvent using commercially available aldehydes, (phenylsulfonyl)acetonitrile, cumyl hydroperoxide and 1,2-phenylendiamines. Medicinally relevant 3-aryl/alkyl-substituted heterocycles are isolated in generally good to high overall yield and high enantioselectivity (up to 99 % ee). A rare example of excellent reusability of an organocatalyst at higher scale, subjected to oxidative conditions, is demonstrated. Mechanistically, labile α-ketosulfone has been detected as the intermediate involved in the DROC process. Theoretical calculations on the key epoxidation step rationalize the observed stereocontrol, highlighting the important role played by the sulfone group.

Copper-catalyzed direct coupling of benzoxazin-2-ones with indoles for the synthesis of diverse 3-indolylbenzoxazin-2-ones: access to natural cephalandole A

Diverse and functionalized 3-indolyl benzo[b][1,4]oxazin-2-ones were synthesized via copper-catalyzed direct coupling of benzo[b][1,4]oxazin-2-one and indoles in air.

Rhodium-catalyzed asymmetric arylation of N- and O-containing cyclic aldimines: facile and efficient access to highly optically active 3,4-dihydrobenzo[1,4]oxazin-2-ones and dihydroquinoxalinones

A highly enantioselective Rh-catalyzed arylation of benzoxazinones and quinoxalinones with arylboroxines was realized for the first time by employing a simple sulfur-olefin as the ligand.

Progress in Studies on Rutaecarpine. II.--Synthesis and Structure-Biological Activity Relationships

Rutaecarpine is a pentacyclic indolopyridoquinazolinone alkaloid found in Evodia rutaecarpa and other related herbs. It has a variety of intriguing biological properties, which continue to attract the academic and industrial interest. Studies on rutaecarpine have included isolation from new natural sources, development of new synthetic methods for its total synthesis, the discovery of new biological activities, metabolism, toxicology, and establishment of analytical methods for determining rutaecarpine content. The present review focuses on the synthesis, biological activities, and structure-activity relationships of rutaecarpine derivatives, with respect to their antiplatelet, vasodilatory, cytotoxic, and anticholinesterase activities.

A short and highly convergent approach for the synthesis of rutaecarpine derivatives

Synthesis of rutaecarpine analogues is accomplished from anthranilamide and chloroaldehyde through the halocyclization strategy.

New topoisomerases inhibitors: synthesis of rutaecarpine derivatives and their inhibitory activity against topoisomerases

A series of rutaecarpine derivatives were prepared by employing previously reported methods and their inhibitory activities against topoisomerase I and II were evaluated. Among them, strongly cytotoxic 10-bromorutaecarpine and 3-chlororutaecarpine showed strong inhibitory activities against topo I and II.

Synthesis and biological properties of benzo-annulated rutaecarpines

A series of benzo-annulated rutaecarpines were prepared from anthranilic acid and 3-aminonaphthalene-2-carboxylic acid by Fischer indole synthesis as key reaction. Cytotoxicity was somewhat increased by the introduction of benzo-annulation, which was not directly related to the inhibitory activity against topoisomerases (topo) I and II. Benzo-annulation on ring A led to significant increase of inhibitory activity against topo II while annulations on ring E increased inhibitory activity against topo I.