Water → HCID 87198363, compound

2,4-Dichloro-6-methyl-3-nitropyridine (15.0 g, 72.5 mmol) was dissolved in concentrated sulfuric acid (73 mL) under ice-cold conditions and added with chromic acid (21.7 g, 217 mmol). The resultant mixture was stirred overnight by gradually warming to room temperature. After completion of the reaction, ice water was added under ice-cold conditions and the resultant mixture was filtered. Tetrahydran was added thereto, and the resultant mixture was concentrated in vacuo to obtain a crude product (15.7 g). The obtained crude product (15.7 g) was dissolved in tetrahydrofuran (180 mL) and methanol (180 mL). The reaction solution was added with triethylamine (90 mL, 652 mmol) and methyl ester chloroformate (34 mL, 435 mmol) under ice-cold conditions, and the resultant mixture was stirred for 10 minutes. After completion of the reaction, water was added, and the resultant mixture was extracted with ethyl acetate. The organic layer was washed with a saturated aqueous solution of ammonium chloride, dried over sodium sulfate, and concentrated in vacuo. The obtained residue was purified using column chromatography (chloroform/methanol), and methyl 4,6-dichloro-5-nitropicolinate (12.6 g, yield 69%) was obtained as a yellow crystal.

1. additionwas added under ice-cold conditions
2. filtrationthe resultant mixture was filtered
3. additionTetrahydran was added
4. concentrationthe resultant mixture was concentrated in vacuo
5. customto obtain a crude product (15.7 g)
6. customThe obtained crude product (15.7 g)
7. additionwas added
8. extractionthe resultant mixture was extracted with ethyl acetate
9. washThe organic layer was washed with a saturated aqueous solution of ammonium chloride
10. dry with materialdried over sodium sulfate
11. concentrationconcentrated in vacuo
12. customThe obtained residue was purified

ORD record

ord-ea865e737df145b48da23fda5b6c07f8

Source dataset

uspto-grants-2012_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08153634B2