Hydrochloric Acid → 4-Bromo-N1-methylbenzene-1,2-diamine

A mixture of iron (5.88 g, 105 mmol), ethanol (16 mL) and 2 M hydrochloric acid (3.1 mL) was sparged with nitrogen for 10 min, then heated to reflux. A solution of 4-bromo-N-methyl-2-nitroaniline (1.43 g, 6.19 mmol) in ethanol (14 mL), methanol (3 mL) and ethyl acetate (2 mL) was added to the hot mixture and the reaction stirred at reflux for 1 h. After this time, the reaction was cooled to room temperature and adjusted to pH 8-9 with potassium carbonate (˜850 mg). The mixture was filtered through diatomaceous earth and the filter cake washed with methanol (300 mL). The filtrate was concentrated under reduced pressure and the resulting residue purified by chromatography (silica, gradient, methylene chloride to 19:1 methylene chloride/methanol) to afford 4-bromo-N1-methylbenzene-1,2-diamine. 1H NMR (400 MHz, DMSO-d6) δ 6.65 (d, J=2.4 Hz, 1H), 6.60 (dd, J=8.4, 2.4 Hz, 1H), 6.26 (d, J=8.4 Hz, 1H), 4.74 (s, 2H), 4.72-4.69 (m, 1H), 2.67 (d, J=5.2 Hz, 3H).

1. customwas sparged with nitrogen for 10 min
2. temperatureheated to reflux
3. temperatureat reflux for 1 h
4. filtrationThe mixture was filtered through diatomaceous earth
5. washthe filter cake washed with methanol (300 mL)
6. concentrationThe filtrate was concentrated under reduced pressure
7. customthe resulting residue purified by chromatography (silica, gradient, methylene chloride to 19:1 methylene chloride/methanol)

ORD record

ord-39248faed78a433988641fd4b461789f

Source dataset

uspto-grants-2016_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09376441B2