Reaction Steps
In a 50 mL round-bottomed flask was dissolved tert-butyl (5S,6S)-6-(2,3-difluorophenyl)-9-(2-oxo-2-(4-(2-oxo-2,3-dihydro-1H-imidazo[4,5-b]pyridin-1-yl)piperidin-1-yl)ethyl)-6,7-dihydro-5H-cyclohepta[b]pyrazin-5-ylcarbamate (58.6 mg, 0.093 mmol) in methylene chloride (1 mL). trifluoroacetic acid (0.5 mL) was added, and the mixture was stirred at rt for 1 h. LCMS showed complete conversion. Volatile components were removed in vacuo, and the residue was partitioned between ethyl acetate/0.5N sodium hydroxide/saturated sodium bicarbonate solution. The layers were separated. The organic layer was dried and concentrated to give a tan oil. flash column chromatography up to 10% methanol (2M ammonia) in methylene chloride afforded the desired product (36 mg, 73%) as a tan solid: MS (ESI)[M+H+]=532.3; 1H NMR (400 MHz, CDCl3) δ 8.47 (ddd, J=11.4, 8.1, 2.5 Hz, 2H), 8.07 (d, J=5.1 Hz, 1H), 7.46 (t, J=6.7 Hz, 1H), 7.30 (d, J=7.9 Hz, 1H), 7.20 (d, J=7.1 Hz, 1H), 7.08 (dt, J=14.8, 7.7 Hz, 2H), 6.99 (td, J=8.2, 5.3 Hz, 2H), 6.41 (dt, J=22.6, 7.2 Hz, 1H), 4.90-4.68 (m, 2H), 4.56 (dd, J=17.3, 12.7 Hz, 1H), 4.15 (ddd, J=24.9, 20.2, 15.2 Hz, 2H), 3.83 (dt, J=7.2, 6.4 Hz, 1H), 3.64 (dd, J=33.2, 16.2 Hz, 1H), 3.26 (t, J=13.1 Hz, 1H), 2.69 (dd, J=28.5, 13.4 Hz, 1H), 2.39 (d, J=6.8 Hz, 2H), 2.33-2.05 (m, 3H), 2.03-1.69 (m, 2H); 19F NMR (376 MHz, CDCl3) δ −137.26-−138.00 (m), −142.22 (dd, J=96.1, 21.6 Hz).
