A facile and versatile synthesis of heteropolycyclic compounds from 4-amino-1-azabutadienes via friedel-crafts cyclization of their heterocyclic derivatives.
groups, readily accesible from 4-amino-1-azabutadienes, undergo cyclization under mild acidic conditions to produce benzo[f]isoquinolines and benzo[h]quinazolines, as well as a new 8,13-diazasteroid derivative.
The intramolecular Friedel-Crafts type cyclization of several heterocycles prepared from 4-amino-1-azabutadienes leading to the preparation of several azaphenanthrene and azasteroid structures, using phosphoric or trifluoromethanesulfonic acid, is described. The reactions are carried out under mild conditions, and good yields are obtained. In some cases, such as the cyclization of thiazine 5, the reaction is totally regioselective.