Methods for controlling the regioselection in the reaction of 3‐amino‐5‐benzylthio‐1,2,4‐triazole with acetylacetaldehyde dimethyl acetal

Abstract The reaction of 3‐amino‐5‐benzylthio‐1,2,4‐triazole with acetylacetaldehyde dimethyl acetal affords 2‐benzylthio‐5‐methyl‐1,2,4‐triazolo[1,5a]pyrimidine or 2‐benzylthio‐7‐methyl‐1,2,4‐triazolo[1,5a]pyrimidine regioselectively depending on the reaction conditions.