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

Participants

Reaction Steps

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]+.

Provenance & Evidence