Hydrogen Bromide → 2-Bromo-6-methoxy-1,3-benzothiazole

Participants

Reaction Conditions

Reaction Steps

[(2-(6-Methoxybenzothiazolyl))carbonyl]-1-piperidinecarboxylic acid, 1,1-dimethylethyl ester ##STR32## Slurry 2-amino-6-methoxybenzothiazole (0.255 mol) in water (325 mL), heat to reflux and add 48% hydrobromic acid (130 mL). Maintain at reflux for 20 minutes, cool to 0° C. and add a solution of sodium nitrite (17.56 g, 0.255 mol) in water (90 mL), maintaining a temperature of 0° C. Stir at 0° C. for 15 minutes and add by dropwise addition (while keeping cold) to a rapidly stirring mixture of copper (I) bromide (42.03 g,0.293 mol) in 48% hydrobromic acid (86 mL) and water (225 mL). Stir at room temperature for 20 minutes. Allow to stand overnight, extract into methylene chloride and dry (MgSO4). Evaporate the solvent in vacuo and purify by chromatography to give 2-bromo-6-methoxybenzothiazole.

Provenance & Evidence