Hydrochloric Acid → 5-(trifluoromethyl)-1,3-benzothiazole-2-thiol

Participants

Reaction Conditions

Reaction Steps

Carbon disulphide (2.28 g, 30 mmol) was added dropwise over a period of 1 minute to a solution of potassium hydroxide (0.33 g, 5.9 mmol) in a mixture of water (2 ml) and methanol (5 ml), and the resulting yellow solution stirred for 5 minutes, followed by the addition of 2-nitro-4-trifluoromethyl thiophenol (1.10 g, 5 mmol). To this mixture was added dropwise over a period of 5 minutes a solution of potassium hydroxide (1.97 g, 35 mmol) and sodium dithionite (3.1 g, 15 mmol) in water (14 ml), so that the temperature did not exceed 40° C. The resultant orange mixture was stirred at 40°-50° C. for 2 hours. The reaction mixture was cooled to 10° C. and slowly acidified to pH 5-6 with concentrated HCl, and the mixture stirred for half an hour at this temperature. The off-white solid was washed with water and air dried to give the product. The yield was 0.81 g (70%).

Provenance & Evidence