Nitric Acid → Nitro-oxazine

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.

1. temperatureThe light yellow solution was cooled in an ethanol/ice bath
2. temperaturecooling for 30 minutes
3. additionpoured carefully onto ice-water (30 ml)
4. extractionextracted 3 times with ethyl acetate
5. dry with materialThe combined extracts were dried over Na2SO4
6. filtrationfiltered
7. concentrationconcentrated in vacuo
8. customThe crude product was purified on silica gel [Eluent: Heptane/ethyl acetate (0% to 50%)]

ORD record

ord-3360c647cae74b37a5d44dbc06aa3ef5

Source dataset

uspto-grants-2013_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08476264B2