Nitric Acid → Nitro-oxazine

Participants

Reaction Steps

Oxazine XXIV (1.27 mmol) was dissolved in sulfuric acid (10.2 g, 5.57 ml, 102 mmol, Eq: 80). The light yellow solution was cooled in an ethanol/ice bath. Nitric acid fuming (1.78 mmol) was added dropwise over a period of 1 minute. The mixture was stirred under ice-bath cooling for 30 minutes and poured carefully onto ice-water (30 ml). The mixture was basified with a 5N NaOH solution and extracted 3 times with ethyl acetate. The combined extracts were dried over Na2SO4, filtered and concentrated in vacuo. The crude product was purified on silica gel [Eluent: Heptane/ethyl acetate (0% to 50%)] to afford the pure nitro-oxazine XXV.

Provenance & Evidence