Hydrochloric Acid → Methyl 6-chloro-2-thioxo-2,3-dihydrobenzoxazole-4-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a mixture of methyl 2-amino-5-chloro-3-hydroxybenzoate (4.00 g, 19.84 mmol) in anhydrous pyridine (30 mL) was added potassium-O-ethylxanthate (3.50 g, 21.82 mmol), and the reaction mixture heated to 125° C. for 3 h under nitrogen atmosphere. The warm solution was poured into a mixture of concentrated HCl (12 mL) and ice (120 mL), the resulting precipitate filtered, and dried under vacuum to provide methyl 6-chloro-2-thioxo-2,3-dihydrobenzoxazole-4-carboxylate (4.80 g, 99%) as a yellow solid: 1H NMR (300 MHz, CDCl3) δ 8.10 (s, 1H), 7.81 (d, J=1.9 Hz, 1H), 7.48 (d, J=1.9 Hz, 1H), 4.01 (s, 3H); MS (ESI+) m/z 244 (M+H).

Provenance & Evidence