Ring Transformation of Fused Pyridazines. III. 1-Substituted Phthalazines with Ynamines

Abstract

In the reaction of 1-substituted phthalazines with ynamines, there are three patterns of ring transformation, giving naphthalene derivatives through addition-cyclization-denitrogenation (type A), giving benzodiazocine derivatives through addition-cyclization-ring expansion (type B), and giving penta-substituted pyridine derivatives through N-N bond cleavage of the pyridazine ring (type C). In these reactions, it is considered that the substituent group at the 1-position of the phthalazine ring is a significant factor determining the outcome.