Methanesulfonic Acid → (5S)-2-(5-{3-[(1S)-2-Methoxy-1-methylethoxy]-5-[(triisopropylsilyl)oxy]phenyl}-1H-pyrrol-2-yl)-5-methyl-4,5-dihydro-1,3-oxazole

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Reaction Conditions

Reaction Steps

N-[(2R)-2-hydroxypropyl]-5-{3-[(1S)-2-methoxy-1-methylethoxy]-5-[(triisopropylsilyl)oxy]phenyl}-1H-pyrrole-2-carboxamide (48.7 g, 96.5 mmol) synthesized in Example (116b) was dissolved in tetrahydrofuran (600 mL), and anhydrous methanesulfonic acid (33.6 g, 193 mmol) and triethylamine (40.4 mL, 289 mmol) were added, followed by stirring at 50° C. for 3 hours under nitrogen atmosphere. To the reaction solution, a saturated aqueous ammonium chloride solution (500 mL) was added, and extraction was carried out twice with ethyl acetate (500 mL). The organic layer was washed with saturated brine, and subsequently dried over anhydrous magnesium sulfate. The solvent was distilled off under reduced pressure, diisopropylether (300 mL) was added to the resulting residue, and the slurry was stirred to give a white solid, which was filtered off. Under reduced pressure, the solvent in the mother liquor was distilled off, and the resulting residue was purified using silica gel column chromatography (elution solvent: ethyl acetate/hexane=10%-50%). This was vacuum-dried together with the filtered product to afford the desired compound (34.8 g, yield 74%) as a white solid.

Provenance & Evidence