Acetic Acid → 1-Oxo-3-(4-trifluoromethyl-phenyl)-1,2-dihydro-pyrrolo[1,2-a]pyrazine-6-carboxamidine

Participants

Reaction Conditions

Reaction Steps

A mixture of N-hydroxy-1-oxo-3-(4-trifluoromethyl-phenyl)-1,2-dihydro-pyrrolo[1,2-a]pyrazine-6-carboxamidine (Example 3) (0.03 g, 89.2 μmol) suspended in methanol (1.5 mL) and glacial acetic acid (0.15 mL) was treated with 10% palladium on carbon (5 mg). The reaction was stirred at room temperature under hydrogen (1 atm) at 50° C. for 2 h. The reaction was treated with ammonium formate (16.9 mg, 0.27 mmol) and then heated at reflux for 5 h. The reaction mixture was treated with slurry of Raney nickel in water (˜0.2 mL). The resulting mixture was stirred under hydrogen (1 atm) at room temperature overnight. At this time the reaction was filtered through Celite®. The filtrate was concentrated in vacuo to afford a light yellow semi-solid. The solid was triturated with diethyl ether, collected by filtration and then dried in vacuo to afford a light green solid. This solid was further triturated with a saturated aqueous sodium bicarbonate solution, collected by filtration and dried in vacuo to afford 1-oxo-3-(4-trifluoromethyl-phenyl)-1,2-dihydro-pyrrolo[1,2-a]pyrazine-6-carboxamidine (13 mg, 44%) as light brown solid. 1H NMR (methanol-d4) δ ppm 8.11 (s, 1H), 7.92 (d, J=8.8 Hz, 2H), 7.78-7.84 (m, 3H), 7.50-7.56 (m, 1H). LC-MS calcd. for C15H11F3N4O [(M+H)+] 321, obsd. 321.0.

Provenance & Evidence