Efficient Synthesis of (1,2,3‐Triazol‐1‐yl)methylpyrimidines from 5‐Bromo‐1,1,1‐trifluoro‐4‐methoxypent‐3‐en‐2‐one

5‐Bromo‐1,1,1‐trifluoro‐4‐methoxypent‐3‐en‐2‐one was used as an efficient precursor for the synthesis of a new series of (1,2,3‐triazol‐1‐yl)methyl‐pyrimidine biheterocycles. For this stepwise synthesis, the 5‐bromo‐1,1,1‐trifluoro‐4‐methoxypent‐3‐en‐2‐one was first converted into 5‐azido‐1,1,1‐trifluoro‐4‐methoxypent‐3‐en‐2‐one through a nucleophilic substitution of the bromine by an azide group. This was then followed by an azide–alkyne cycloaddition reaction (click chemistry) to give the key intermediate 5‐[4‐alkyl(aryl)‐1H‐1,2,3‐triazol‐1‐yl]‐1,1,1‐trifluoro‐4‐methoxypent‐3‐en‐2‐ones. These were cyclocondensed with 2‐methylisothiourea sulfate to give a series of 2‐(methylthio)‐4‐(1,2,3‐triazol‐1‐yl)methyl‐6‐(trifluoromethyl)pyrimidines. Additionally, the 2‐methylthiopyrimidine products were used to prepare a new series of 2‐amino‐4‐(1,2,3‐triazol‐1‐yl)methyl‐6‐(trifluoromethyl)pyrimidines. 5‐Bromo‐1,1,1‐trifluoro‐4‐methoxypent‐3‐en‐2‐one is an efficient precursor for the synthesis of (1,2,3‐triazol‐1‐yl)methylpyrimidines.