反应详情

A solution of crude tert-butyl ((5R,6S)-5-(2-fluoro-5-nitrophenyl)-6-(2-hydroxyethyl)-2,2,5-trimethyl-1,1-dioxido-5,6-dihydro-2H-1,4-thiazin-3-yl)carbamate (250 mg, 0.528 mmol) in THF (5 ml) and DMF (0.5 ml) was treated portionwise with NaH (60% suspension in mineral oil) (52.8 mg, 1.320 mmol). After initial gas evolution the reaction mixture became dark red. The mixture was stirred at RT for 10 min. The mixture was quenched with NH4Cl solution and diluted with EtOAc. Water was added to dissolve solids, and the organic layer was separated, washed with brine and concentrated. The residue was purified by FC on 12 g RedSep Gold column using 10-100% EtOAc in heptane. All the fractions containing both epimers were combined and concentrated to afford tert-butyl ((11bR)-3,3,11b-trimethyl-10-nitro-4,4-dioxido-4a,5,6,11b-tetrahydro-3H-benzo[6,7]oxepino[4,5-b][1,4]thiazin-2-yl)carbamate (196 mg, 0.432 mmol, 82% yield) as a mixture of epimers at C4. Ratio by NMR 2:1 favoring trans-isomer.

1. customThe mixture was quenched with NH4Cl solution
2. additiondiluted with EtOAc
3. additionWater was added
4. dissolutionto dissolve solids
5. customthe organic layer was separated
6. washwashed with brine
7. concentrationconcentrated
8. customThe residue was purified by FC on 12 g RedSep Gold column
9. additionAll the fractions containing both epimers
10. concentrationconcentrated