Reaction Steps
A suspension of the crude regioisomeric mixture of 4-({tert-butoxycarbonyl-[1-(4-methoxy-benzyl)-1H-[1,2,3]triazol-4-ylmethyl]-amino}-methyl)-phenylboronic acid and 4-({tert-butoxycarbonyl-[3-(4-methoxy-benzyl)-3H-[1,2,3]triazol-4-ylmethyl]-amino}-methyl)-phenylboronic acid (1008 and 1009, 37.62 g, 83.23 mmol) and N-[3-(3-fluoro-4-iodo-phenyl)-2-oxo-oxazolidin-5-ylmethyl]-acetamide (1010, 28.32 g, 74.9 mmol, 0.90 equiv) in toluene (150 mL) was treated with powder K2CO3 (34.45 g, 249.7 mol, 3.0 equiv), EtOH (50 mL), and H2O (50 mL) at 25° C., and the resulting mixture was degassed three times under a steady stream of Argon at 25° C. Pd(PPh3)4 (866 mg, 0.749 mmol, 0.01 equiv) was subsequently added to the reaction mixture, and the resulting reaction mixture was degassed three times again under a stead stream of Argon at 25° C. before being warmed up to gentle reflux for 18 h. When TLC and HPLC/MS showed the coupling reaction was complete, the reaction mixture was cooled down to room temperature before being treated with H2O (100 mL) and ethyl acetate (100 mL). The two layers were then separated, and the aqueous layer was extracted with EtOAc (100 mL). The combined organic extracts were washed with H2O (50 mL), 1.5 N aqueous HCl solution (2×150 mL), H2O (100 mL), and the saturated aqueous NaCl solution (100 mL), dried over MgSO4, and concentrated in vacuo. The residual oil was solidified upon standing at room temperature in vacuo to afford the crude, (5S)-{4′-[5-(acetylamino-methyl)-2-oxo-oxazolidin-3-yl]-2′-fluoro-biphenyl-4-ylmethyl}-[1-(4-methoxy-benzyl)-1H-[1,2,3]triazol-4-ylmethyl]-carbamic acid tert-butyl ester (1011) and (5S)-{4′-[5-(acetylamino-methyl)-2-oxo-oxazolidin-3-yl]-2′-fluoro-biphenyl-4-y methyl}-[1-(4-methoxy-benzyl)-1H-[1,2,3]triazol-5-ylmethyl]-carbamic acid tert-butyl ester (1012) as a regioisomeric mixture. This crude product (43.36 g, 49.28 g theoretical, 88%) was used directly in the subsequent reaction without further purification. For the mixture of 1011 and 1012: 1H NMR (300 MHz, DMSO-d6) δ 1.35 and 1.38 (two br. s, 9H, COO(CH3)3), 1.85 (s, 3H, COCH3), 3.45 (t, 2H, J=5.4 Hz), 3.73 and 3.76 (two s, 3H, Ar—OCH3), 3.79 (dd, 1H, J=6.6, 9.1 Hz), 4.18 (t, 1H, J=9.1 Hz), 4.35-4.43 (m, 4H), 4.73-4.81 (m, 1H), 5.50 (br. s, 2H), 6.90 and 6.98 (two d, 2H, J=8.7 Hz), 7.28 and 7.32 (two d, 2H, J=8.7 Hz), 7.35 (dd, 2H, J=2.2, 8.6 Hz), 7.42 (dd, 1H, J=2.2, 8.6 Hz), 7.49-7.63 (m, 4H, aromatic-H), 7.90 and 7.99 (two br. s, 1H, triazole-CH), 8.29 (t, 1H, J=5.8 Hz, NHCOCH3); C35H39FN6O6, LCMS (EI) m/e 659 (M++H) and 681 (M++Na).
