Product name：Ethyl 5-methylisoxazole-3-carboxylate
Product use：Basic raw materials, organic intermediates, pharmaceutical intermediates
The synthesis process is as follows:
hydroxylammonium sulfate; ethanol; toluene;
Reactants are commercially availlable.
PFIZER INC., EP150984, B1, (1991) (i) Ethyl 5-methylisoxazol-3-carboxylate A mixture of 0.16 mole ethyl 2,4-dioxovalerate and 0.08 mol e hydroxylamine sulfate, 50 ml ethanol and 70 ml toluene was stirred at 40°C. for four hours. The mixture was cooled to 15-20°C., 1.8 g of concentrated ammonium hydroxide added and stirring continu ed at room temperature for 60 hours. The mixture was poured into water/toluene, the aqueous layer e xtracted with toluene, the organic layers combined, washed with brine and dried (Na2SO4). Evaporation of solvent in vacuo gave a yellow liquid which was distilled to afford 14.68 g of product, b.p. 12 0-124°C. at 30 torr which crystallized upon standing.