Copper-catalyzed aerobic oxidative domino cyclization of methyl azaarenes with 6-amino-pyrimidine-2,4-diones and pyrazol-5-amines: access to dipyrimidine/dipyrazolo-fused pyridines

An aerobic copper-catalyzed oxidative domino cyclization of methyl azaarenes with 6-amino-pyrimidine-2,4-diones and pyrazol-5-amines has been developed, which enables access to dipyrimidine/dipyrazolo-fused pyridines. Cu(OTf)2 is used as a transition-metal catalyst. The oxidative annulation procedure exhibits excellent catalytic efficiency, high functional group compatibility and broad substrate scope, such as methyl quinolines, 2-methyl quinoxaline, 2-methyl benzo[f]quinoline, 2-methyl benzothiazole, 2-methyl benzoxazole and methyl pyridines.