Diisopropyl Ether → 6-(4-Oxo-4H-1,3-benzothiazin-2-yl)-2-pyridinecarboxylic acid

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Reaction Steps

A mixture of tert-butyl 6-(4-oxo-4H-1,3-benzothiazin-2-yl)-2-pyridinecarboxylate (400 mg, 1.1 mmol) and trifluoroacetic acid (10 ml) was stirred under ice cooling condition for 3 hrs. The reaction mixture was combined with diisopropylether to precipitate crystals, which were collected by filtration and recrystallized from methanol-diisopropylether to give the titled compound (245 mg, 73%).

Provenance & Evidence