Citric Acid → 3-(1,1-dioxido-4H-1,2,4-benzothiadiazin-3-yl)-4-hydroxy-1,1-dipropyl-2(1H)-naphthalenone

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Reaction Conditions

Reaction Steps

A suspension of the product of Example 1G (150 mg, 0.34 mmol) in 10% potassium hydroxide solution (9 mL) was stirred at 130° C. for 30 hours, cooled to 25° C., acidified to pH 3 by addition of 1 M citric acid, stirred with ethyl acetate, and filtered through Celite®. The organic layer from the filtrate was washed with saturated sodium chloride solution, dried (Na2SO4), filtered and concentrated in vacuo. The residue was recrystallized from ether-hexane solution to afford the title compound (83 mg, 57%). 1H NMR (300 MHz, CDCl3): δ16.70 (s, 1 H), 14.22 (s, 1 H), 8.26 (d, J=8.09 Hz, 1 H), 7.99 (d, J=8.09 Hz, 1 H), 7.67 (m, 1H), 7.47 (m, 3 H), 7.29 (m, 2 H), 2.25 (m, 2 H), 1.86 (m, 2 H), 0.89 (m, 2 H), 0.70 (m, 8 H).

Provenance & Evidence