反应详情

1M Borane in THF (17.18 mL, 17.18 mmol) was added to (S)-tert-butyl 1-(2-(7-nitro-2H-benzo[b][1,4]thiazin-4(3H)-yl)-2-oxoethyl)pyrrolidine-2-carboxylate (1.4 g, 3.44 mmol), and the resulting yellow solution was stirred at room temperature overnight (17 hours). The yellow solution was cooled to 0° C. and carefully quenched with MeOH (10 mL). The solution was concentrated, dissolved in MeOH (50 mL), and concentrated again to give a dark yellow residue. This residue was subjected to silica gel chromatography using the Biotage purification system (column: Silicycle 80 g; 20:80 EtOAc:hexanes gradient to 60:40 EtOAc:hexanes over 10 column volumes; flow rate=45 mL/min; collection wavelength: 254 nm). A yellow residue was obtained (550 mg, 40.7%). 1H-NMR (CDCl3) δ 7.96 (d, J=2.7 Hz, 1H), 7.87 (dd, J=2.7, 9.3 Hz, 1H), 6.68 (d, J=9.3 Hz, 1H), 3.86-3.82 (m, 2H), 3.57 (t, J=7.5 Hz, 2H), 3.24-3.10 (m, 2H), 3.05-2.96 (m, 3H), 2.75-2.63 (m, 1H), 2.52-2.41 (m, 1H), 2.15-2.04 (m, 1H), 1.97-1.78 (m, 3H), 1.44 (s, 9H); ESI-MS (m/z, %): 394 (MH+, 25), 338 (100).

1. temperatureThe yellow solution was cooled to 0° C.
2. customcarefully quenched with MeOH (10 mL)
3. concentrationThe solution was concentrated
4. dissolutiondissolved in MeOH (50 mL)
5. concentrationconcentrated again
6. customto give a dark yellow residue
7. customthe Biotage purification system (column: Silicycle 80 g; 20:80 EtOAc:hexanes gradient to 60:40 EtOAc:hexanes over 10 column volumes; flow rate=45 mL/min; collection wavelength: 254 nm)
8. customA yellow residue was obtained (550 mg, 40.7%)