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 mL), 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 mL)
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-4fc7ac8112cb40818e102e3deced6f43

Source dataset

uspto-grants-2008_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07468393B2