SYNTHETIC REACTIONS OF -CYANO-4H-[1]BENZOPYRAN-4-YL)PROPANE-1,3-DINITRILE WITH REACTIVE METHYLENE-COMPOUNDS

Derivatives of dibenzo[b,d]pyran, [1]benzopyrano[2,3-b] pyridine, [1] benzopyrano[3,4-c]pyridine and [1]benzopyrano[4,3,2-de][1,6]naphthyrid ine are obtained from the reaction of 2-(2-amino-3-cyano-4H-[1 ]benzop yran-4-yl)propane-1,3-dinitrile with compounds containing a reactive m ethylene group. Consideration of these reactions suggests that the dic yanomethyl group is released from the 4-position of the starting mater ial, and that it then reacts at the 2-position of the newly formed imi nium ion. The 4-position is now available for Michael addition of a co mpound containing a reactive methylene group, but the nature of the fi nal product depends on the substituents on the methylene group.