Miscellaneous Name Reactions

IBD-mediated oxidative cyclization of pyrimidinylhydrazones and concurrent Dimroth rearrangement: Synthesis of [1,2,4]triazolo[1,5-c]pyrimidine derivatives

“…This kind of rearrangement has been described previously [10–11 21]. The accepted mechanism of the Dimroth rearrangement might involve protonation of 5 to give I ( 5-H + ), ring opening ( II ), tautomerization by H-shift ( III ) of the 1,2,4-triazole ring, ring closure ( IV ) and deprotonation to isomeric 1,2,4-triazolo[1,5- c ] pyrimidine 6 (Scheme 2).…”