Hydrochloric Acid → 5-{[(5-Chloro-1,3-thiazol-2-yl)amino]sulfonyl}pyridine-2-carboxylic acid

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Reaction Steps

2-Amino-5-chlorothiazole hydrochloride (2.63 g, 15.4 mmol, 3.96 eq) was dissolved in pyridine (10 ml) and stirred at room temperature for 10 minutes before the addition of methyl 5-(chlorosulfonyl)pyridine-2-carboxylate (Preparation 16, 915 mg, 3.8 mmol, 1 eq) portionwise and the resulting reaction mixture stirred at room temperature for a further hour. The mixture was dropped slowly into 6M HCl (20 ml), extracted into ethyl acetate (15 ml), washed with saturated sodium hydrogen carbonate (15 ml), dried over sodium sulphate, filtered and evaporated in vacuo. The residue was suspended in dioxane (5 ml), a solution of sodium hydroxide (300 mg, 7.5 mmol, 1.9 eq) in water (2 ml) was added and the reaction mixture stirred at room temperature for 30 minutes. The reaction mixture was washed with ethyl acetate (10 ml). The remaining aqueous phase diluted with brine (10 ml), acidified to pH 1, extracted into ethyl acetate (10 ml), dried over sodium sulphate, filtered and evaporated in vacuo to yield the title compound as an orange solid (90 mg, 0.28 mmol, 7%).

Provenance & Evidence