To a solution of ethyl 2-chloro-3-oxopropionate (4.5 g, 30.0 mmol) and thiobenzamide (4.1 g, 30.0 mmol) in toluene (50 mL) was added magnesium sulfate heptahydrate (7.2 g, 59.8 mmol). The reaction mixture was stirred at 100 °C for 4 h. Upon completion of the reaction, the reaction was quenched with ice water (100 mL). Subsequently, the reaction mixture was extracted with ether (3 x 50 mL), the organic phases were combined, washed with saturated brine (50 mL) and dried over anhydrous sodium sulfate. The drier was removed by filtration and the filtrate was concentrated under reduced pressure to give the crude product ethyl 2-phenylthiazole-5-carboxylate. The crude product was purified by silica gel column chromatography, using petroleum ether/ethyl acetate (10:1) as eluent, the target fraction was collected, and the pure ethyl 2-phenylthiazole-5-carboxylate was obtained after concentration under reduced pressure (3.2 g, 45.9% yield). Mass spectrum (ESI) m/z: 234.1 [M+H]+.
