Palladium-catalyzed heteroarylamination of ethyl 2-chloro-1-azaazulene-3-carboxylate and annulation of heteroarylamino-1-azaazulenes

The palladium catalyzed heteroarylamination of ethyl 2-chloro-l-azaazulene-3-carboxylate was achieved using a catalyst based on Pd 2 (dba) 3 / Xantphos system. Treatment of ethyl 2-(heteroarylamino)-1-aza-azulene-3-carboxylates with a PPA-POCl 3 mixture gave corresponding annulation products. 2-(2-Benzothiazolylamino)-l-azaazulene (3h) showed anticancer activity against HeLa S3 cells (IC 50 : 6.5 μM).