反应详情

A solution of tert-butyl 2-hydroxyethyl(2-(7-nitro-2H-benzo[b][1,4]thiazin-4(3H)-yl)-2-oxoethyl)carbamate (250 mg, 0.629 mmol) in THF (10 mL) was cooled to 0° C. then treated with borane in THF (1M) (6.29 mL, 6.29 mmol). The resulting bright yellow solution was allowed to warm to room temperature and then stirred at this temperature for 2.5 days. The mixture was cooled to 0° C., and the reaction was then carefully quenched with MeOH (dropwise addition at first; 20 mL total). The cooling bath was removed, and the yellow solution was stirred for 20 minutes then concentrated. The orange residue was dissolved in MeOH (50 mL) and concentrated to dryness. This residue was dissolved in EtOAc (20 mL) and filtered through a pad of silica gel. The silica pad was eluted with EtOAc (100 mL). The filtrate was concentrated to give an orange residue which was dried under reduced pressure for 4 hours (230 mg, 95%). 1H-NMR (CDCl3) δ 7.97 (brs, 1H), 7.87 (brd, J=8.7 Hz, 1H), 6.85-6.71 (m, 1H), 3.81 (brs, 5H), 3.61 (brs, 2H), 4.54-3.31 (m, 4H), 3.02 (overlapping t, 2H), 1.47 (brs, 9H); ESI-MS (m/z, %): 406 (M+Na, 60), 384 (MH+, 10), 328 (60), 284 (100).

1. temperatureThe mixture was cooled to 0° C.
2. customthe reaction was then carefully quenched with MeOH (
3. additiondropwise addition at first
4. customThe cooling bath was removed
5. stirringthe yellow solution was stirred for 20 minutes
6. concentrationthen concentrated
7. dissolutionThe orange residue was dissolved in MeOH (50 mL)
8. concentrationconcentrated to dryness
9. dissolutionThis residue was dissolved in EtOAc (20 mL)
10. filtrationfiltered through a pad of silica gel
11. washThe silica pad was eluted with EtOAc (100 mL)
12. concentrationThe filtrate was concentrated
13. customto give an orange residue which
14. customwas dried under reduced pressure for 4 hours (230 mg, 95%)