Hydrogen Bromide → 2-Bromoimidazo[5,1-b]thiazole

Participants

Reaction Conditions

Reaction Steps

2-Bromoimidazo[5,1-b]thiazole-7-carboxylic acid (0.52 g, 2.10 mmol) was suspended in a mixed solvent composed of water (4.0 ml) and acetic acid (6.0 ml). 48 wt % hydrobromic acid (0.75 g, 4.42 mmol) was added to the suspension at room temperature, and the mixture was stirred at 105° C. for about 22 hr. After the completion of the reaction, ethyl acetate (5 ml), a 25 wt % aqueous solution of sodium hydroxide (10 ml), and sodium carbonate (1.63 g, 15.38 mmol) were added to the reaction solution. The mixture was adjusted to pH 6, followed by separation. After the separation, the aqueous layer was extracted twice with 5 ml of ethyl acetate. Thereafter, the organic layers were combined, were washed with 15 wt % brine (5 ml), were then dehydrated over magnesium sulfate, and were evaporated to dryness. The residue was further dried under the reduced pressure with an oil pump to give 2-bromoimidazo[5.1-b]thiazole (0.40 g, yield 93.8%) as a white solid.

Provenance & Evidence