2-Methyl-2-butene → 4-Iodo-2-methoxypyridine-3-carboxylic acid

To a solution of 4-iodo-2-methoxy-pyridine-3-carbaldehyde (4.96 g, 18.9 mmol) in 22 mL tert.-butanol was added in this order 2-methyl-2-butene (30 mL of a 2 M solution in THF, 60 mmol), natriumdihydrogen-phosphate (5.7 g, 47.5 mmol), water (15 mL) and sodiumchlorite (3.9 g, 43 mmol). The mixture was stirred at ambient temperature for 1 hour, then poured on dilute aqueous formic acid. The mixture was extracted with ethyl acetate, the organic layer washed with water and brine and concentrated. The residue was dissolved in diisopropylether+dichloromethane (1+1) and extracted 3 times with half-concentrated aqueous NaOH solution. The combined aqueous layers were acidified with conc. HCl and extracted with ethyl acetate. The organic layers were washed with water and brine, then dried over sodium sulfate and concentrated to give 3.462 g of the title compound as a white solid (67%). 1H NMR (500 MHz, CD3OD) δ 7.83 (d, J=5.4 Hz, 1H), 7.43 (d, J=5.4 Hz, 1H), 3.94 (s, 3H);

1. extractionThe mixture was extracted with ethyl acetate
2. washthe organic layer washed with water and brine
3. concentrationconcentrated
4. dissolutionThe residue was dissolved in diisopropylether+dichloromethane (1+1)
5. extractionextracted 3 times with half-concentrated aqueous NaOH solution
6. extractionextracted with ethyl acetate
7. washThe organic layers were washed with water and brine
8. dry with materialdried over sodium sulfate
9. concentrationconcentrated

ORD record

ord-95f44250f2ae4abf80b18a4681f20a35

Source dataset

uspto-grants-2007_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07189716B2