Nitric Acid → HCID 178526809, compound

25 mL of fuming H2SO4 under cold conditions (0° C.) is added dropwise to a stirred solution of 4-hydroxy-2-trifluoromethylpyridine [Chemistry of Heterocyclic Compounds 1997, 33, 995-996] (4 g, 24.5 mmol) in concentrated H2SO4 (10 mL). HNO3 (fuming, 90%, 25 mL) is added carefully to the above mixture with caution to keep the offset of any exotherm under control, and the reaction is allowed to warm to room temperature slowly. After heating at 120° C. for 6 h with stirring, the resulting mixture is cooled to room temperature, poured into ice-cold water maintaining the pH around 1 with the addition of 10N NaOH solution, and then extracted with CHCl3. The combined organic phase is washed successively with saturated aqueous NaHCO3, water, brine, dried over Na2SO4, and concentrated in vacuo to afford 5-nitro-2-trifluoromethyl-pyridin-4-ol as an yellow solid. 1H NMR (300 MHz, CDCl3) δ 9.33 (s, 1H), 7.50 (s, 1H).

1. temperatureAfter heating at 120° C. for 6 h
2. temperaturethe resulting mixture is cooled to room temperature
3. additionpoured into ice-cold water maintaining the pH around 1
4. extractionextracted with CHCl3
5. washThe combined organic phase is washed successively with saturated aqueous NaHCO3, water, brine
6. dry with materialdried over Na2SO4
7. concentrationconcentrated in vacuo

ORD record

ord-7c99d7fc31df40d6a31ae6d7ba3f3569

Source dataset

uspto-grants-2010_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07642267B2