Zn-catalyzed hydrohydrazination of propargylamides with BocNHNH2: a novel entry into the 1,2,4-triazine core

Hydrohydrazination of a variety of propargylamides with BocNHNH(2) 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 K-3[Fe(CN)(6)]. This provides a new entry into the medicinally important 1,2,4-triazine core.