Synthesis of benzofuro[3,2-b]furo[2,3-d]pyridin-4(5H)-ones, derivatives of a novel heterocyclic system

Methyl 2-[(cyanophenoxy)methyl]-3-furoates obtained from methyl 2-(chloromethyl)-3-furoate and salicylonitriles undergo tandem cyclization in the presence of excess t-BuOK in N,N-dimethylformamide (DMF) solution at 65°C to give substituted benzofuro[3,2-b]furo[2,3-d]pyridin-4(5H)-ones, derivatives of a novel heterocyclic system.