Methanol → 2-(5-(2-chloropyridin-4-yl)-2-methyl-3-(2-(phenylsulfonyl)benzyl)-1H-pyrrol-1-yl)acetic acid

Participants

Reaction Steps

To a solution of crude benzyl 2-(5-(2-chloropyridin-4-yl)-2-methyl-3-(2-(phenylsulfonyl)benzyl)-1H-pyrrol-1-yl)acetate (514 mg, 0.360 mmol, contaminated with ˜60% 2-(phenylsulfonyl)phenyl)methanol) in tetrahydrofuran (4 mL) and water (4 mL) was added a 3M solution of aqueous sodium hydroxide (28.8 mg, 0.720 mmol). The reaction turned yellow upon addition of the base solution, and the reaction was stirred at room temperature for 20 minutes after which LCMS analysis indicated that the saponification was complete. The reaction was concentrated to remove the THF, and then diluted in water and washed with dichloromethane (2×50 mL) and ethyl acetate (1×50 mL). The water layer was acidified to pH=4 with 3M aqueous hydrochloric acid solution. The product was extracted with ethyl acetate and washed with a brined aqueous layer (3×50 mL), dried (sodium sulfate), filtered and concentrated to a yellow solid. A significant loss of product was observed. In order to recover additional product, the aqueous layer prior to the final extraction was further acidified and re-extracted with ethyl acetate (3×50 mL), dried (sodium sulfate), filtered and concentrated. The batches were combined to afford 2-(5-(2-chloropyridin-4-yl)-2-methyl-3-(2-(phenylsulfonyl)benzyl)-1H-pyrrol-1-yl)acetic acid as a yellow solid (99.5 mg, 0.207 mmol, 58% yield). 1H NMR (400 MHz, CDCl3): δ (ppm) 8.31 (d, 1H), 8.27 (d, 1H), 7.85 (m, 2H), 7.40-7.56 (m, 5H), 7.13-7.16 (m, 2H), 7.04 (d, 1H), 5.85 (s, 1H), 4.64 (s, 2H), 4.05 (s, 2H), 2.00 (s, 3H).

Provenance & Evidence