We report a facile method to synthesize novel alkyl selanyl[1,2,4]triazolo[4,3-a]pyrimidine heterocyclic scaffolds. A diverse library of selenide derivatives has been prepared via the treatment of 5-bromo-2,4-dichloro-6-methylpyrimidine with potassium selenocyanate as the source of selenium. The selenocyanate anion as the nucleophile is applied to produce 5-bromo-2-chloro-4-methyl-6-selenocyanatopyrimidine (2). The interaction of compound (2) with various alkyl halides afforded alkyl selanyl pyrimidine (3a–e). Then, the treatment of alkyl selanyl pyrimidine (3a–e) with hydrazine hydrate gave the corresponding derivatives (4a–e) which react with various orthoesters to prepare the relative alkyl selanyl[1,2,4]triazolo[4,3-a]pyrimidine (5a–o) in good to excellent yields. The chemical structures of the whole products have been evaluated by spectroscopic analyses.

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