Isopropanol → 2-Chloro-5-(ethoxycarbonyl)-1,3-thiazole-4-carboxylic acid

Participants

Reaction Steps

To a solution of ethyl 2-chloro-4-(hydroxymethyl)-1,3-thiazole-5-carboxylate (Intermediate 8, 2.5 g, 11 mmol) in acetone at 0° C. was slowly added a solution of chromium trioxide (2.26 g, 22 mmol) in 20% conc. Sulfuric acid in water (20 mL). After stirring at room temperature for 2 hrs, isopropanol (1 mL) was added to quench unreacted chromium trioxide. The reaction was diluted with water and the acetone was removed. Partitioning with methylene chloride (×3), drying with MgSO4 and concentrating yielded a white solid (2.3 g, 90%). MS (ES): 236 (M+H+) for C7H6ClNO4S; NMR: 1.26 (t, 3H), 4.31 (q, 2H), 13.99-14.15 (m, 1H).

Provenance & Evidence