2-Chloro-5-methoxy-3-methyl-4-nitropyridine 1-oxide → 2-Chloro-5-methoxy-3-methylpyridin-4-amine

Temperature

100 °C

Iron powder (700 mg, 12 mmol) was added to a solution of C3 (350 mg, 1.60 mmol) in acetic acid (8 mL), and the reaction mixture was heated at 100° C. for 1 hour, then cooled to room temperature. After filtration through Celite and thorough washing of the filter pad with ethyl acetate and methanol, the combined filtrates were concentrated in vacuo. The residue was diluted with saturated aqueous sodium bicarbonate solution and extracted with ethyl acetate. The combined organic layers were washed with water, washed with saturated aqueous sodium chloride solution, dried over magnesium sulfate, filtered, and concentrated under reduced pressure. Silica gel chromatography (Gradient: 50% to 75% ethyl acetate in heptane) afforded the product as a white solid. Yield: 240 mg, 1.39 mmol, 87%. LCMS m/z 173.0 [M+H+]. 1H NMR (400 MHz, CDCl3) δ 7.65 (s, 1H), 4.38 (br s, 2H), 3.91 (s, 3H), 2.20 (s, 3H).

1. temperaturecooled to room temperature
2. filtrationAfter filtration through Celite
3. washthorough washing of the filter pad with ethyl acetate and methanol
4. concentrationthe combined filtrates were concentrated in vacuo
5. additionThe residue was diluted with saturated aqueous sodium bicarbonate solution
6. extractionextracted with ethyl acetate
7. washThe combined organic layers were washed with water
8. washwashed with saturated aqueous sodium chloride solution
9. dry with materialdried over magnesium sulfate
10. filtrationfiltered
11. concentrationconcentrated under reduced pressure

ORD record

ord-7a105ab0add34efd920d0f06225b4355

Source dataset

uspto-grants-2014_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08822494B2