Diisopropylethylamine → Tert-butyl 4-(2-chloro-6-(3,3-difluoropyrrolidin-1-yl)pyridin-4-yl)piperidine-1-carboxylate

Participants

Reaction Steps

A solution of 3,3-difluoropyridine hydrochloride (533 mg, 3.72 mmol, 3.18 equiv), tert-butyl 4-(2,6-dichloropyridin-4-yl)piperidine-1-carboxylate (1.00 g, 1.17 mmol, 1 equiv), and N,N-diisopropylethylamine (1.23 mL, 7.03 mmol, 6.00 equiv) in N-methylpyrrolidinone (2.3 mL) was heated at 130° C. in the microwave (CEM) for 1.5 h. The reaction mixture was diluted with ethyl acetate (50 mL), and the resulting solution was washed with saturated aqueous ammonium chloride solution (2×20 mL). The aqueous washes were extracted with ethyl acetate (25 mL). The combined organic was washed with water (25 mL), dried over anhydrous sodium sulfate, filtered, and concentrated. Purification by flash column chromatography (4:1 heptane/ethyl acetate) provided product as a clear oil (220 mg, 47% yield). 1H NMR (400 MHz, CDCl3): 6.51 (s, 1H), 6.03 (s, 1H), 4.25 (m, 2H), 3.83 (t, J=13.1 Hz, 2H), 3.67 (t, J=7.3 Hz, 2H), 2.77 (m, 2H), 2.42-2.58 (m, 3H), 1.78 (m, 2H), 1.53-1.62 (m, 2H), 1.48 (s, 9H).

Provenance & Evidence