Nitric Acid → 4-Chloro-5-fluoro-2-nitrophenol

4-chloro-3-fluorophenol (2.38 g, 16.2 mmol) was dissolved in DCE (32 mL) and tetrabutylammonium bromide (0.524 g, 1.62 mmol) was added. HNO3 70% (2.1 mL, 32 mmol) was diluted with H2O (18.9 mL) to make a 7% HNO3 solution. This solution was added to the reaction mixture which was then stirred at rt for 4 h at which time the reaction was judged complete by TLC. The reaction was poured into H2O and extracted with DCM (3×). The combined organic layers were dried over MgSO4, filtered and concentrated in vacuo. The resulting residue was adsorbed onto silica gel and flash chromatographed to give the title compound of step A (2.29 g, 74%). 1H NMR (400 MHz, DMSO-d6) δ ppm 11.76 (br. s., 1H), 8.18 (d, J=8.1 Hz, 1H), 7.10 (d, J=10.6 Hz, 1H).

1. additionThis solution was added to the reaction mixture which
2. extractionextracted with DCM (3×)
3. dry with materialThe combined organic layers were dried over MgSO4
4. filtrationfiltered
5. concentrationconcentrated in vacuo
6. customchromatographed

ORD-Eintrag

ord-9b8cbc5acf824ffa9d64e1d032796504

Quelldatensatz

uspto-grants-2012_01

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08093239B2