Synthesis of indeno[2,1-b][1,4]benzothiazine derivatives from 2-bromoinden-1-ones

2-Bromoinden-1-ones 2 were condensed with 6-substituted 3-aminopyridine-2(1H)-thiones to produce a new type of 4-azaindeno2,1-b]1,4]benzothiazine derivatives 3 . Substituted 6-phenylindeno2,1-b]1,4]benzothiazines 4 were also prepared by reacting 2-bromo-5-methoxy- and 2,6-dibromo-5-methoxyinden-1-ones with o-aminobenzenethiol.