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

The synthesis of new tetracyclic 4 H ‐furo[3,2‐ g ]pyrrolo[3,2,1‐ ij ]quinolin‐4‐ones, 15–17 , 1 H ,5 H ‐benzofuro[5,6, 7‐ ij ]quinolizin‐5‐ones, 18–20 , and 3 H ,5 H ‐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.