Synthesis of Pyridazine Derivatives via Aza-Diels-Alder Reactions of 1,2,3-Triazine Derivatives and 1-Propynylamines.

A highly regioselective method was developed for the preparation of pyridazine derivatives via the aza-Diels-Alder reaction of 1,2,3-triazines with 1-propynylamines under neutral conditions. This methodology allowed direct access to a wide range of 6-aryl-pyridazin-3-amines in high yields with good functional group compatibility. Key features of this strategy included a broad substrate scope and simple, metal-free, and neutral reaction conditions.