Solid-Phase Synthesis of Biologically Active Benzoannelated Nitrogen Heterocycles: An Update

Rhodium-catalyzed oxidative coupling/cyclization of 2-phenylindoles with alkynes via C-H and N-H bond cleavages with air as the oxidant

The straightforward and efficient synthesis of indolo[2,1-a]isoquinoline derivatives has been achieved by the rhodium-catalyzed aerobic oxidative coupling/cyclization of 2-phenylindoles with alkynes. Some of the polycyclic products exhibit solid-state fluorescence.

Solid-phase synthesis of N-substituted pyrrolidinone-tethered N-substituted piperidines via Ugi reaction

Starting with resin-bound glutamic acid, an efficient synthesis of N-substituted pyrrolidinones is described, using the Ugi four-component reaction (U-4CR). The same methodology is employed to produce N-substituted pyrrolidinone tethered N-substituted piperidines.

Solid phase synthesis of 2-aminobenzothiazoles

A traceless solid supported protocol for the synthesis of 2-aminobenzothiazoles is described, employing resin-bound acyl-isothiocyanate and a series of anilines. Cyclization of the resulting N-acyl, N'-phenyl-thioureas generates the 2-aminobenzothiazole scaffold, which can be further elaborated prior to hydrazine-mediated cleavage of the final products from the carboxy-polystyrene resin. A small, focused library of 2-aminobenzothiazoles was prepared.

Rapid synthesis of the indole-indolone scaffold via [3+2] annulation of arynes by methyl indole-2-carboxylates

The reaction of methyl indole-2-carboxylates and arynes affords a very efficient, high yielding synthesis of a novel indole-indolone ring system, which tolerates considerable functionality, is broad in scope and proceeds under mild reaction conditions.