22876-19-3

Synthesis of compound 19: A mixture of potassium ethylxanthate (13.4 g, 84.0 mmol) and 4-chloro-2-aminophenol (10 g, 69.6 mmol) was dissolved in anhydrous ethanol (200 mL). The reaction mixture was stirred under reflux conditions overnight. After completion of the reaction, it was cooled to room temperature and the solvent was removed by evaporation under reduced pressure. The residue was dissolved in water (200 mL) and the pH was adjusted with acetic acid (HOAc) to 5. A solid product was precipitated, filtered and dried to afford 5-chloro-2-mercaptobenzoxazole (12.8 g, 99.1% yield).

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