Acetic Acid → 2-Ethylamino-5-nitro-phenol

Participants

Reaction Conditions

Reaction Steps

2-Methyl-6-nitro-benzoxazole (12.25 g, 68.76 mmol) was dissolved in Tetrahydrofuran (500 mL) and Acetic acid (4.00 mL, 70.4 mmol) and was cooled at 0° C. Sodium tetrahydroborate (5.20 g, 138 mmol) was added over 10 min and the reaction was stirred at 0° C. for 30 min, then warmed to room temperature and stirred an additional 2.5 h. The undissolved borohydride was removed by filtration, and the filtrate conc. in vacuo to 100 mL. The filtrate was poured into water (800 mL) and neutralized with sodium bicarbonate powder. The aq. was extracted 3×200 mL DCM; the org. extract was washed with 100 mL water and 200 mL 1:1 brine:satd. sodium bicarbonate sol., then dried over sodium sulfate before being filtered through a ½″ h×2″ diameter plug of silica gel, washing with 500 mL 1:1 DCM:EtOAc. The filtrate was conc. to give 2-Ethylamino-5-nitro-phenol as a yellow solid (11.5 g, 92%)

Provenance & Evidence