Hydrochloric Acid → 2-Amino-6-benzothiazolol

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.

1. temperaturethe mixture was heated
2. temperatureunder reflux for 16 hr
3. temperaturethe mixture was heated
4. temperatureunder reflux for 12 hr
5. temperaturethe mixture was heated
6. temperatureunder reflux for 16 hr
7. customstood at 0° C
8. filtrationThe resulting dark-gray crystals were collected by filtration
9. dissolutionThe obtained crystals were dissolved in methanol (35 mL)
10. dry with materialethyl acetate (350 mL) and dried over anhydrous magnesium sulfate
11. filtrationThe insoluble material was filtered off
12. concentrationthe filtrate was concentrated

ORD record

ord-cd88e1d0d316410da2fb28a3825055d9

Source dataset

uspto-grants-2012_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08324395B2