Ethyl orthopropionate → 2-ethyl-5-nitro-1,3-benzoxazole

Participants

Reaction Steps

A solution of 2-amino-4-nitrophenol (2.00 g, 12.98 mmol) and triethyl orthopropionate (4.57 g, 25.95 mmol) in anhydrous ethanol (15 ml) was treated with p-toluenesulphonic acid (20 mg) and the resulting mixture refluxed for 3 h. On cooling to room temperature a precipitate formed which was filtered off and dried to afford the title compound (2.11 g) as a beige solid m.p. 88-90°. δH (CDCl3) 1.48 (3H, t, J 7.6 Hz), 3.02 (2H, q, J 7.6 Hz), 7.57 (1H, d, J 9.0 Hz), 8.27 (1H, dd, J 2.3, 9.0 Hz) and 8.55 (1H, d, J 2.3 Hz).

Provenance & Evidence