Trifluoroacetic acid → 3-(pyrazin-2-yl)-6,7-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one

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Reaction Steps

To a solution of 2-(trimethylsilyl)ethyl 8-oxo-3-(pyrazin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-carboxylate (1.0 g, 2.9 mmol) in DCM (29 mL) was added TFA (5.7 mL, 75 mmol). After 1 h, the reaction mixture was concentrated. The crude residue was diluted with EtOAc, sonicated, and filtered to provide the desired product as a white solid (1.2 g, 95%). MS (ESI): mass calcd. for C9H8N6O, 216.1; m/z found, 217.1 [M+H]+. 1H NMR (500 MHz, DMSO-d6) δ 9.39 (d, J=1.1 Hz, 1H), 8.77 (q, J=2.6 Hz, 2H), 8.56 (s, 1H), 4.73-4.60 (m, 2H), 3.67-3.55 (m, 2H).

Provenance & Evidence