Hydrochloric Acid → Pentoxazone

Participants

Reaction Conditions

Reaction Steps

Ethyl N-(4-chloro-5-cyclopentyloxy-2-fluorophenyl)carbamate (6.02 g, 20 mmol), ferric chloride (53.5 mg, 0.33 mmol) and tributylamine (185 mg, 1.00 -mmol) were introduced into a two-necked flask (50 cc) equipped with a distillation unit and heated to 200° C. Ethyl 2-hydroxy-3-methyl-3-butenoate (4.33 g, 30 mmol) was added dropwise to the mixed solution over 30 minutes, and after the addition, the solution was stirred at 200° C. for 3.5 hours. After completion of the reaction, the reaction solution was allowed to cool to 70 to 80° C., and a mixed solution consisting of methanol (10 mL) and 6N hydrochloric acid (0.5 mL) was added thereto and mixed homogeneously. Then, the reaction solution was left to stand at room temperature. The precipitated solid was collected by filtration, washed with a mixed solution consisting of methanol (20 mL) and 6N hydrochloric acid (1 mL) and then water (20 mL) and dried completely under reduced pressure to obtain 3-(4-chloro-5-cyclopentyloxy-2-fluorophenyl)-5-isopropylidene-1,3-oxazolidine-2,4-dione (4.77 g, yield 67.4%).

Provenance & Evidence