Trifluoroacetic acid → 2-[trans-2-phenylcyclopropyl]tetrahydroimidazo[1,5-a]pyrazine-1,3(2H,5H)-dione

Participants

Reaction Steps

A solution of A4 in DCM (0.5 M) was cooled to 0° C. (ice bath) and TFA (9 eq.) was added and the reaction was stirred at RT overnight. The solvent was removed under reduced pressure. The crude material was treated with Et2O (20 mL) and HCl (1N, 12 mL). The two layers were separated, and organic phase washed with water (2×15 mL). To the combined organic extracts was added solid K2CO3 in small portion until pH 9-10. The mixture was extracted with DCM and combined extracts were dried and evaporated under reduced pressure to yield (100%) the desired compound that was used crude in the next step. 1H NMR (400 MHz, DMSO-d6, 300K) δ 7.29-7.20 (5H, m), 3.90 (1H, m), 3.78 (1H, m), 3.15 (1H, m), 2.85 (3H, m), 2.65 (1H, m), 2.50-2.30 (3H, m), 1.5 (1H, m), 1.35 (1H, m). MS (ES+) C15H17N3O2 requires 271, found: 272 (M+H)+.

Provenance & Evidence