Ethyl 2,4-dioxovalerate → Ethyl 5-methylisoxazole-3-carboxylate

Participants

Reaction Steps

A mixture of ethyl 2,4-dioxovalerate (25 ml, 178 mmol), hydroxylamine hydrochloride (13.7 g, 197 mmol) and sodium bicarbonate (15.4 g, 183 mmol) in ethanol (125 ml) were heated at reflux for 2.5 h, cooled and the solvent removed under reduced pressure. The residue was taken up in chloroform and washed with water, the organic layer separated and dried (MgSO4). Solvent removal and distillation under reduced pressure gave the desired product (15.44 g, 100 mmol, 56%); b.p. 82°-86° C. at 0.5 mm Hg; νmax (film) 3120, 2980, 2930, 1730, 1600, 1450, 1270, 1200, 1100, 1020, 915, 830, 780 cm-1 ; δH (CDCl3) 1.40 (3H, t, J 7 Hz, OCH2CH3), 2.50 (3H, s, CH3 -5), 4.40 (2H, q, J 7 Hz, OCH2CH3), 6.40 (1 H, s, CH-4).

Provenance & Evidence