Triethylamine → tert-butyl 4-[3-((3R)-3-{[(1S)-1-(5-bromopyridin-3-yl)-3-tert-butoxy-3-oxopropyl]carbamoyl}piperidin-1-yl)-3-oxopropyl]piperidine-1-carboxylate

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Reaction Steps

To tert-butyl (3S)-3-amino-3-(5-bromopyridin-3-yl)propanoate (1.33 g, 4.42 mmol) in DMF (17 mL) was added tert-butyl 4-{3-[(3R)-3-{[(2,5-dioxopyrrolidin-1-yl)oxy]carbonyl}piperidin-1-yl]-3-oxopropyl}piperidine-1-carboxylate (example 25c 2.54 g, 4.91 mmol) and triethylamine (1.85 mL, 13.2 mmol) in dichloromethane (17 mL) at 0° C. After 3 hours the mixture was quenched by addition of saturated aqueous ammonium chloride solution, phases were separated and the aqueous phase was extracted with diethyl ether. Combined organic extracts were dried over sodium sulphate, concentrated under reduced pressure and the residue was purified by chromatography on silica gel (ethyl acetate in hexane, 12 to 100% followed by methanol in ethyl acetate 0 to 15%) to yield 2.1 g of tert-butyl 4-[3-((3R)-3-{[(1S)-1-(5-bromopyridin-3-yl)-3-tert-butoxy-3-oxopropyl]carbamoyl}piperidin-1-yl)-3-oxopropyl]piperidine-1-carboxylate.

Provenance & Evidence