Pyrido[2′1′:2,3]imidazo[4,5‐c]isoquinoline and the alkylation of pyrido[2′,1′:2,3]imidazo[4,5‐c]isoquinolin‐5(6H)‐one

The reaction of 2‐aminopyridine, o‐phthaldehydic acid and potassium cyanide gave pyrido[2′,1′:2,3]imidazo[4,5‐c]isoquinolin‐5(6H)‐one, which upon treatment with propargylbromide, yielded both O and N alkylated products. 2‐Aminopyridine, o‐phthaldehyde and potassium cyanide gave 1‐cyano‐2‐(2‐pyridyl)isoindole which rearranged in acid to give the previously unreported parent pyrido[2′,1′:2,3]imidazo[4,5‐c]isoquinole. Structures were confirmed using uv, ir, nmr and x‐ray spectroscopy.