Four series of linear tricyclic and quadricyclic heterocyclic derivati
ves related to oxolinic acid have been prepared: 1H-pyrido[3,4-g]quino
lin-4-ones (1), 1H-pyrido[3,2-g]quinolin-4-ones (2), 1H,11H-pyrido[3,2
-b] acridine-4,6-diones (8)and 1H,10H-indolo[3,2-g]quinolin-4-ones (10
).