Zn‐Catalyzed Hydrohydrazination of Propargylamides with BocNHNH2: A Novel Entry into the 1,2,4‐Triazine Core.

Hydrohydrazination of a variety of propargylamides with BocNHNH2 under Zn(OTf)2 catalysis, unexpectedly, gave dihydro-1,2,4-triazines with a loss of the protecting group. The initial products can be efficiently aromatized in situ with K3[Fe(CN)6]. This provides a new entry into the medicinally important 1,2,4-triazine core.