68774-77-6

Using 2-chloro-3-hydrazinopyrazine (8 g) and triethyl orthoformate (32 mL), the mixture was heated to reflux and stirred for 4 hours. Upon completion of the reaction, the reaction solution was cooled to room temperature, the precipitated solid was collected by filtration and washed with ethanol. The resulting solid was 8-chloro-[1,2,4]triazolo[4,3-A]pyrazine, which was dried under reduced pressure to give the product (8.10 g, 95% yield).

[1] Patent: JP5851663, 2016, B1. Location in patent: Paragraph 0301
[2] Patent: WO2009/64418, 2009, A1. Location in patent: Page/Page column 85
[3] Patent: US2010/120774, 2010, A1. Location in patent: Page/Page column 37-38