Lithium Hydroxide → 2-Bromo-1,3-thiazole-4-carboxylic acid

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Reaction Steps

To a solution of 2-bromo-thiazole-4-carboxylic acid ethyl ester (Combi-Blocks, Inc., San Diego, Calif.; 5 g, 21.2 mmol) in MeOH (25 mL) and water (25 mL) was added LiOH (0.56 g, 23.3 mmol). After stirring for 4 h at reflux temperature, MeOH was evaporated in vacuo. To the residue was added more water, the mixture was acidified to pH 2 with concentrated HCl (3 mL), and extracted with EtOAc. The combined extracts were evaporated to give 2-bromo-thiazole-4-carboxylic acid which was used without further purification. The compounds of the present invention were preferably prepared by methods A to F:

Provenance & Evidence