Nitric Acid → 5-Bromo-4-chloro-3-nitropyridin-2-amine

Temperatur

-10 °C

5-Bromo-4-chloro-pyridin-2-ylamine (0.640 g, 3.0 mmol) was added in portions to conc. H2SO4 (6 ml) while the temperature kept at −10° C. The reaction mixture was then stirred at −10° C. for 15 min. The resulting solution was then heated at 55° C. and HNO3 (208 μL, 3.2 mmol) was added dropwise while the temperature was kept at 55° C.-60° C. maximum. The reaction mixture was stirred at 55° C. for 30 min then cooled to room temperature and poured slowly into ice (20 g). The pH was adjusted to 7 with 40% aqueous NaOH. The precipitated product was filtered, washed with water (20 ml) and dried in vacuo over P2O5 for 16 h to give the title compound as a yellow solid (0.580 g). 0.48 g was further purified by chromatography (hexane/ethyl acetate; v/v 7:3) to give the title compound as a yellow solid (0.287 g); 1H-NMR (250 MHz, CDCl3) 8.29 (s, 1H, 6-H).

1. customkept at −10° C
2. temperatureThe resulting solution was then heated at 55° C.
3. customwas kept at 55° C.-60° C.
4. stirringThe reaction mixture was stirred at 55° C. for 30 min
5. temperaturethen cooled to room temperature
6. filtrationThe precipitated product was filtered
7. washwashed with water (20 ml)
8. dry with materialdried in vacuo over P2O5 for 16 h

ORD-Eintrag

ord-2f7b01b5cf604ef6852b38c04c4fb8a7

Quelldatensatz

uspto-grants-2012_01

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08088761B2