Acetic Acid → 4-[2-(5-Bromo-pyrazin-2-ylamino)-ethyl]-piperidine-1,4-dicarboxylic acid 1-tert-butyl ester 4-ethyl ester

Participants

Reaction Steps

To a solution of 5-bromo-2-pyrazinamine (0.35 g, 2.01 mmol) in 1-2 dichloroethane (DCE, 5.0 mL) was added a solution of 4-(2-oxo-ethyl)-piperidine-1,4-dicarboxylic acid 1-tert-butyl ester 4-ethyl ester (0.722 g, 2.41 mmol) in DCE (2.0 mL), acetic acid (3.1 eq) and allowed to stir at room temperature for an hour. NaBH(OAc)3 (3.0 eq.) was then added in one portion and reaction mixture was allowed to stir at room temperature for 16 hours. The reaction mixture was then diluted with DCM (5 mL), quenched with 2 M of NH4OH in water. The layers were separated, and the aqueous layer was extracted with DCM (5.0 mL×2). The combined organic layers were washed with aqueous NaHCO3 (15 mL), brine (30 mL), and dried over Na2SO4, and concentrated under vacuum. Purification by column chromatography on silica gel eluting with methanol in dichloromethane (0-10%) afforded 0.85 g (77%) of title compound.

Provenance & Evidence