Reaction Steps
To a solution of 4-(3-amino-6-((1S,3S,4S)-3-fluoro-4-hydroxycyclohexyl)pyrazin-2-yl)-2-fluorobenzoic acid (300 g, 95% assay, 815.8 mmol) and (S)—N-(2-amino-2-(3-bromo-5-fluorophenyl)ethyl)-N-methyl-2-nitrobenzenesulfonamide hydrochloride (397.7 g, 848.5 mmol) in DMF (2.5 kg) was added DIPEA (421.8 g, 3263.4 mmol), followed by EDCl (312.8 g, 1631.7 mmol) and HOAt (222.1 g, 1631.7 mmol). After the reaction mixture was stirred at 25° C. for 18 hours, the reaction temperature was lowered to 10° C. before IPAC (3.5 kg) and water (4.0 kg) was added. The mixture was stirred for 10 minutes and then the layers were separated. The aqueous layer was extracted with IPAC (2.5 kg). The combined organic layers were washed successively with 10% aqueous Na2CO3 (4.5 kg) and water (2×4 kg), and then concentrated under vacuum (<100 mbar) at 40-45° C. to give 4-(3-amino-6-((1S,3S,4S)-3-fluoro-4-hydroxycyclohexyl)pyrazin-2-yl)-N—((S)-1-(3-bromo-5-fluorophenyl)-2-(N-methyl-2-nitrophenylsulfonamido)ethyl)-2-fluorobenzamide as a foam (670 g, assay purity is 93%), which was used in next step without further purification. ESI-MS (m/z): 763.1216, 765.1161 ([M+H]+, 100). Mp=115-117° C. HPLC (method A), retention time=10.57 min. 1H NMR (400 MHz, CDCl3): 8.11 (t, J=8 Hz, 1H), 7.99 (m, 1H), 7.91 (s, 1H), 7.59-7.72 (m, 5H), 7.35 (s, 1H), 7.19 (d, J=8 Hz, 1H), 7.09 (d, J=8 Hz, 1H), 5.46 (br. s, 1H), 4.77 (br. s, 2H), 4.48-4.55, 4.35-4.42 (m, 1H), 3.93 (q, J1=12 Hz, J1=16 Hz, 1H), 3.73-3.82 (m, 1H), 3.33 (q, J1=4 Hz, J1=12 Hz, 1H), 3.00 (s, 3H), 2.78-2.85 (m, 1H), 2.31-2.37 (m, 1H), 2.12-2.20 (m, 1H), 1.84-1.96 (m, 2H), 1.60-1.71 (m, 1H), 1.47-1.56 (m, 1H).
