Hydrochloric Acid → 2-Amino-6-benzothiazolol

Participants

Reaction Steps

6-Methoxy-1,3-benzothiazole-2-amine (10.4 g, 57.8 mmol) was dissolved in 25% hydrogen bromide acetic acid solution (80 mL), water (40 mL) was added and the mixture was heated under reflux for 16 hr. To the reaction mixture was added sodium iodide (10.4 g, 69.4 mmol) and the mixture was heated under reflux for 12 hr. Sodium iodide (15.2 g, 101 mmol) was added and the mixture was heated under reflux for 16 hr. The reaction mixture was cooled to room temperature, and added to 8N aqueous sodium hydroxide solution (350 mL) stirred vigorously. The reaction mixture was neutralized with 6N hydrochloric acid and stood at 0° C. The resulting dark-gray crystals were collected by filtration and the mother liquid was preserved. The obtained crystals were dissolved in methanol (35 mL) and ethyl acetate (350 mL) and dried over anhydrous magnesium sulfate. The insoluble material was filtered off and the filtrate was concentrated to give the title compound (6.90 g, 72%) as a gray solid.

Provenance & Evidence