Sodium Hydroxide → 3-Bromobenzene-1,2-diamine

To a stirring slurry of tin(II) chloride dihydrate (8.28 g, 37 mmol) in conc. hydrochloric acid (40 mL) was added 2-bromo-6-nitroaniline (prepared as described in WO 02/22600, 1.99 g, 9.2 mmol), and the resulting mixture was stirred at room temperature for 5 min—an exotherm was observed. The mixture was stirred at reflux for 30 min, then allowed to cool to room temperature. The resulting slurry was poured onto crushed ice (˜100 mL), and the pH was adjusted to 14 by addition of sodium hydroxide pellets. The mixture was washed with diethyl ether (5×100 μL), then the combined organic layers were dried over magnesium sulfate and concentrated in vacuo. The crude product was purified on a Biotage SP1 apparatus, using a 2%–20% ethyl acetate in dichloromethane eluant system on a 25M silica column, yielding 1,2-diamino-3-bromobenzene as a brown oil, which solidified upon standing (1.50 g, 87%) m/z (ES+) 187, 189 [MH]+.

1. stirringThe mixture was stirred
2. temperatureat reflux for 30 min
3. temperatureto cool to room temperature
4. additionThe resulting slurry was poured
5. washThe mixture was washed with diethyl ether (5×100 μL)
6. dry with materialthe combined organic layers were dried over magnesium sulfate
7. concentrationconcentrated in vacuo
8. customThe crude product was purified on a Biotage SP1 apparatus

ORD record

ord-348982bac1c64bfbad8f8433b78b3850

Source dataset

uspto-grants-2007_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07217740B2