Synthesis of methyl derivatives of new polycyclic systems of 4H-furo[3,2-g]pyrrolo[3,2,1-ij]quinolin-4-one, of 1H,5H- and 3H,5H-benzofuro[5,6,7-ij]quinolizin-5-one

The synthesis of new tetracyclic 4H-furo[3,2-g]pyrrolo[3,2,1-ij]quinolin-4-ones, 15–17, 1H,5H-benzofuro[5,6, 7-ij]quinolizin-5-ones, 18–20, and 3H,5H-benzofuro[5,6,7-ij]quinolizin-5-ones, 21–23 is described. The planarity of the structure of benzofuroquinolizin-5-one 18 was determined by X-ray single-crystal analysis.