399-66-6

233278-56-3

Platinum(IV) oxide (2.75 g, 12.1 mmol) was added to a suspension of 2-methoxyethanol (150 mL) containing calcium oxide (9.30 g, 166 mmol) and [1,2,4]triazolo[1,5-a]pyrazine (18.10 g, 151 mmol) under nitrogen protection. The reaction mixture was stirred under hydrogen atmosphere for 21.5 h before being filtered through diatomaceous earth and washed with a solvent mixture of dichloromethane/ethanol (9:1). The filtrate was concentrated, co-evaporated with toluene and diisopropyl ether, subsequently dissolved in ethyl acetate, filtered again through diatomaceous earth and washed with ethyl acetate, after which it was concentrated again. The resulting residue was dissolved in hot diisopropyl ether, filtered, washed with diisopropyl ether and finally concentrated under vacuum for 7 hours. The product 5,6,7,8-tetrahydro-[1,2,4]triazolo[1,5-A]pyrazine was obtained in a yield of 17.12 g (92% yield).