Facile access to 5H-thiazolo[2',3':2,3]imidazo[4,5-b]indole derivatives by two-fold Cu-catalysed C-N coupling reactions.

In four simple steps, a series of 5H-thiazolo[2',3':2,3]imidazo[4,5-b]indole and 11H-benzo[4',5']thiazolo[2',3':2,3]imidazo[4,5-b]indole derivatives were prepared with high yields. The key step in this procedure was demonstrated to be two-fold Cu-catalysed C-N coupling reactions of 5-bromo-6-(2-bromophenyl)imidazo[2,1-b]thiazole and 3-bromo-2-(2-bromophenyl)benzo[d]imidazo[2,1-b]thiazole with various amines.