Diethyl Ether → 3-Bromo-2,4-difluoroaniline

Temperature

40 °C

A mixture of 2-bromo-1,3-difluoro-4-nitrobenzene (30 g, 130 mmol) and tin(II) chloride dihydrate in 36% hydrochloric acid (150 ml) was heated to 40° C. Diethyl ether (20 ml) was slowly added to bring about solution. Once in solution the reaction proceeded rapidly and the ether boiled away. After heating at 60° C. for 1 h the reaction was cooled and then poured onto ice-water (1.5 l). The solution was made basic (pH 13) with 30% aq. sodium hydroxide keeping the internal temperature below 20° C. The resulting grey slurry was swirled with chloroform (2×500 ml), the organic extracts were combined, washed with water, dried over an-hydrous magnesium sulfate containing 2 g decolourising charcoal, filtered and evaporated to dryness. Trituration with isohexane afforded 23 g (83%) of the title compound as a buff-coloured solid: 1H NMR (360 MHz, CDCl3) δ 3.51 (2H, br), 6.65–6.70 (1H, mn), 6.75-6-80 (1H, m).

1. temperatureAfter heating at 60° C. for 1 h the reaction
2. temperaturewas cooled
3. additionpoured onto ice-water (1.5 l)
4. customthe internal temperature below 20° C
5. washwashed with water
6. dry with materialdried over an-hydrous magnesium sulfate containing 2 g
7. filtrationfiltered
8. customevaporated to dryness

ORD record

ord-a20f4ec4dfcf4115b70f270c5be8adb6

Source dataset

uspto-grants-2006_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07005431B2