Regioselectivity Change in the Reaction of Naphthalene and 2-Naphthyl Ethers with 1,3,5-Triazines Depending on Reagent Quantities

A new method for the synthesis of 4H-benzo[de]isoquinolin-4-ones has been developed, based on the reaction of 2-naphthyl ethers with an equimolar quantity of 1,3,5-triazines in polyphosphoric acid. With a 2.5 molar excess of 1,3,5-triazines in polyphosphoric acid, the products of 1,6-diacylation (diformylation) are formed. Isoquino[6′,5′,4′:10,5,6]anthra[2,1,9-def]isoquinoline is formed upon reaction of a 1.5 molar excess of 1,3,5-triazine with naphthalene in polyphosphoric acid at 130-140 ˚C.