Hydrogen Bromide → 2-Methyl-1,3-benzothiazol-6-ol

Participants

Reaction Conditions

Reaction Steps

A mixture of 6-methoxy-2-methyl-benzothiazole (19.71 g, 0.11 mol), tetrabutylphosphonium bromide (3.73 g, 0.01 mol), and 48% HBr (120 mL) was stirred at 105° C. for twenty-eight hours before it was cooled to room temperature, neutralized with 10N NaOH (90 mL) and 1N NaOH (45 mL) to pH=4. The resulting precipitate was filtered, washed with water (3×100 mL), dried in vacuo to give the title compound as a pale brown solid (14.81 g): 1H NMR (CDCl3, 200 MHz): δ=7.77 (m, 1H), 7.24 (m, 1H), 6.94 (m, 1H), 5.28 (s, 1H), 2.79 (s, 3H).

Provenance & Evidence