Nitric Acid → Nitro-oxazine

Temperature

0 °C

The oxazine of formula XI (0.1 mmol) was added portionwise to concentrated sulfuric acid (2 ml) at 22° C. The solution obtained was cooled to 0° C. and treated with red fuming nitric acid (0.058 ml) and stirring was continued at 0° C. for 2 hours. For the workup, the reaction mixture was slowly added to crushed ice and the pH was adjusted to 10 using a saturated solution of sodium carbonate. The aqueous layer was extracted with ethyl acetate, the organic layer was dried over sodium sulphate and evaporated to afford the pure nitro-oxazine of formula XII. Alternatively, the crude product was purified by flash chromatography on silica-NH2 gel using mixtures of heptane or cyclohexane and ethyl acetate as the eluent to yield the pure nitro-oxazines of formula XII.

1. customThe solution obtained
2. additionFor the workup, the reaction mixture was slowly added
3. customto crushed ice
4. extractionThe aqueous layer was extracted with ethyl acetate
5. dry with materialthe organic layer was dried over sodium sulphate
6. customevaporated

ORD record

ord-a21b592817f545dc934d640782bcbe98

Source dataset

uspto-grants-2015_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09181232B2