Lithium Hydroxide → 2-[5-Carboxy-2-oxo-1-(2-trimethylsilanyl-ethoxymethyl)-1,2-dihydro-pyridin-3-yl]-indole-1-carboxylic acid tert-butyl ester

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Reaction Steps

Intermediate (1b), 2-[5-methoxycarbonyl-2-oxo-1-(2-trimethylsilanyl-ethoxymethyl)-1,2-dihydro-pyridin-3-yl]-indole-1-carboxylic acid tert-butyl ester (2.88 g, 5.78 mmol) was stirred in a mixture of tetrahydrofuran (40 mL) and water (20 mL). Lithium hydroxide (0.469 g, 11.2 mmol) was added and the reaction stirred at reflux for 2 hours. After cooling the reaction mixture was concentrated in vacuo, and the residue was taken up in water and the pH adjusted to 5 with the careful addition of an aqueous 2M hydrochloric acid solution. This aqueous solution was extracted with dichloromethane (×3), and the combined extracts were washed with brine, dried (Na2SO4) and concentrated in vacuo to afford the desired title compound as a yellow solid 2.30 g, 85%.

Provenance & Evidence