1,3,2-Dioxathiolane, 2,2-dioxide → Esaxerenone

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Reaction Steps

Sodium hydride (0.12 g, 3 mmol, 60% dispersion in mineral oil) was dissolved in N,N-dimethylformamide (1.5 mL), and 4-methyl-N-[4-(methylsulfonyl)phenyl]-5-[2-(trifluoromethyl)phenyl]-1H-pyrrole-3-carboxamide (0.47 g, 1.1 mmol) was added thereto, and then, the resulting mixture was stirred at room temperature for 30 minutes. Then, 1,3,2-dioxathiolane-2,2-dioxide (0.14 g, 1.2 mmol) was added thereto, and the resulting mixture was stirred at room temperature. After 1 hour, sodium hydride (40 mg, 1.0 mmol, oily, 60%) was added thereto again, and the resulting mixture was stirred for 30 minutes. Then, 1,3,2-dioxathiolane-2,2-dioxide (12 mg, 0.11 mmol) was added thereto, and the resulting mixture was stirred at room temperature for 1 hour. After the mixture was concentrated under reduced pressure, methanol (5 mL) was added to the residue and insoluble substances were removed by filtration, and the filtrate was concentrated again. To the residue, tetrahydrofuran (2 mL) and 6 M hydrochloric acid (2 mL) were added, and the resulting mixture was stirred at 60° C. for 16 hours. The reaction was cooled to room temperature, and then dissolved in ethyl acetate, and washed with water and saturated saline. The organic layer was dried over anhydrous sodium sulfate and filtered. Then, the filtrate was concentrated under reduced pressure, and the residue was purified by silica gel column chromatography (ethyl acetate), whereby the objective compound (0.25 g, 48%) was obtained.

Provenance & Evidence