Pyrazine-2-Carboxylic Acid Hydrazide → tert-butyl 3-(pyrazin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-carboxylate

Participants

Reaction Steps

To a solution of tert-butyl 3-ethoxy-5,6-dihydropyrazine-1(2H)-carboxylate (1.14 g, 5 mmol) in 1-butanol (30 mL) was added pyrazine-2-carbohydrazide (685 mg, 5 mmol). The reaction mixture was heated at reflux for 16 h. After cooling to rt, the reaction mixture was concentrated and purified by chromatography (SiO2; 2.5% MeOH in DCM) to afford the desired product as a white solid (700 mg, 50% over 2 steps). MS (ESI): mass calcd. for C14H18N6O2, 302.2; m/z found, 303.2 [M+H]+. 1H NMR (500 MHz, CDCl3) d 9.57 (d, J=1.4 Hz, 1H), 8.62 (d, J=2.5 Hz, 1H), 8.59-8.54 (m, 1H), 4.94 (s, 2H), 4.63-4.50 (m, 2H), 3.89 (t, J=5.4 Hz, 2H), 1.51 (s, 9H).

Provenance & Evidence