Hydrochloric Acid → 6-nitro-3,4-dihydro-2H-1,4-benzoxazine

Participants

Reaction Conditions

Reaction Steps

To a suspension of 6-nitro-2H-benzo[b][1,4]oxazin-3(4H)-one (1.45 g, 7.47 mmol) in THF (11 mL) was added BH3.THF (1 M solution in THF, 60 mL) at rt and the mixture was stirred at 75° C. After 3.5 h, the mixture was cooled to rt. To the cooled mixture was added MeOH (30 mL) and mixture was stirred at rt. After 30 minutes, the mixture was treated with concentrated HCl (6 mL, 72 mmol) and concentrated under reduced pressure. The residue was dissolved in EtOAc (50 mL×4), washed with brine (100 mL×2), dried over Na2SO4, filtered, and concentrated under reduced pressure. The residue was purified by column chromatography on a silica gel column using 0 to 100% gradient of EtOAc in hexane as eluent to give 6-nitro-3,4-dihydro-2H-benzo[b][1,4]oxazine as a reddish-orange solid: Mass Spectrum (ESI) m/e=181.0 (M+1).

Provenance & Evidence