Nitric Acid → 4-Nitro-2,3,5-trimethylpyridine, 1-oxide

The crude residue from example 5 was placed in an ice bath and dissolved in conc. H2SO4 (14 mL). The solution was placed in a 90° C. bath and a mixture of 25 mL conc. H2SO4 and 28 mL conc. nitric acid was added dropwise over one hour, and the reaction was kept at 90° C. until completion. The solution was cooled to ambient temperature and poured onto crushed ice (˜200 g). Solid NaOH (55 g) was added and the mixture was extracted with Ethyl acetate (200×3 mL); the combined organic layers were washed with water (100 mL), brine (50 mL) and dried over anhydrous Na2SO4. The solvent was removed and the yellow residue was purified by column chromatography (5% CH3OH—CH2Cl2) to give the product as a yellow light sensitive solid.

1. customwas placed in a 90° C.
2. additionwas added dropwise over one hour
3. customwas kept at 90° C. until completion
4. additionpoured
5. extractionthe mixture was extracted with Ethyl acetate (200×3 mL)
6. washthe combined organic layers were washed with water (100 mL), brine (50 mL)
7. dry with materialdried over anhydrous Na2SO4
8. customThe solvent was removed
9. customthe yellow residue was purified by column chromatography (5% CH3OH—CH2Cl2)

ORD record

ord-3c9d08ddf7db4154a980b6db1b6c006f

Source dataset

uspto-grants-2009_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07598273B2