m-Chloroperbenzoic acid → Ethyl 3-methylisothiazole-4-carboxylate

Participants

Reaction Steps

To a solution of 3-amino-2-thioformyl-but-2-enoic acid ethyl ester (method 52) (25.6 g, 147 mmol) in ethanol (300 mL), was added m-chloroperbenzoic acid (33.3 g, 77%, 149 mmol) in ethanol (200 mL) dropwise with stirring at room temperature. After the completion of the addition the reaction mixture was heated at 75° C. for 2 h after which the MS showed the complete disappearance of the starting material. The reaction mixture was diluted with ether (500 mL) and the ethereal solution was washed with 0.1 M NaOH solution (3×500 mL) and once with water (400 mL) dried (Na2SO4) and concentrated to get the pure product as light brown oil. Yield 23.5 g (93%). 1NMR (300 MHz) δ: 1.40 (t, 3H), 2.73 (s, 3H), 5.07 (t, 1H), 4.36 (q, 2H), 9.24 (s, 1H).

Provenance & Evidence