Formaldehyde → 5-(Furan-3-yl)-8-(4-methylpiperazin-1-yl)-[1,2,4]triazolo[4,3-a]pyrazine

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Reaction Conditions

Reaction Steps

A 50 mL round bottom flask was charged with 5-(furan-3-yl)-8-(piperazin-1-yl)-[1,2,4]triazolo[4,3-a]pyrazine HCl salt (350 mg, 1.14 mmol), 40% aqueous formaldehyde (20 mL), dichloromethane (20 mL), methanol (20 mL) and sodium cyanoborohydride (245 mg, 3.90 mmol) at 0° C. The resulting mixture was stirred at 20° C. overnight. It was then concentrated in vacuo and the residue was extracted with dichloromethane. The organic layer was washed with brine (10 mL), dried over anhydrous Na2SO4, and concentrated in vacuo. The crude product was re-crystallized from a 1/5 (v/v) dichloromethane/ethyl ether, to afford 0.16 g (49%) of the product as a yellow solid. 1H NMR (300 MHz, CDCl3) δ: 8.83 (s, 1H), 7.76 (dd, J=1.5, 0.9 Hz, 1H), 7.62 (dd, J=1.8, 1.5 Hz, 1H), 7.36 (s, 1H), 6.68 (dd, J=1.8, 0.9 Hz, 1H), 4.41 (br, 4H), 2.59 (t, J=5.1 Hz, 4H), 2.36 (s, 3H). MS m/z: 285 (M+H+).

Provenance & Evidence