General procedure for the synthesis of 3-amino-5-ethylisoxazole from 3-oxovaleronitrile: A portion of the resulting product (0.6 g) was taken and mixed with hydrazine hydrate (0.28 ml) and ethanol (45 ml), and the reaction was heated for 12 hr at 70 °C. After completion of the reaction, the solvent was removed by evaporation and the resulting residue was purified by silica gel column chromatography, using a solvent mixture of dichloromethane and methanol (19:1, v/v) as eluent. The target product 3-amino-5-ethylisoxazole was finally obtained in 51% yield. The product was characterized by 1H NMR (solvent DMSO-d6): δ 1.04 (t, 3H), 2.41 (q, 2H), 4.4 (br s, 2H).
