Acylation of 2-amino-4-chloro-5-isopropylthiazole (I) with 5-bromo-2-methoxybenzenesulfonyl chloride (II) yields sulfonamide (III). Methylation of (III) with ICH3/NaH takes place at the thiazole N, producing (IV). Finally, methyl ether cleavage in (IV) by means of BBr3 in cold CHCl3 affords the title compound.