Sodium Carbonate → tert-butyl 4-(2-chloro-3-fluorophenyl)-5,6-dihydropyridine-1(2H)-carboxylate

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Reaction Conditions

Reaction Steps

A mixture of tert-butyl 4-(((trifluoromethyl)sulfonyl)oxy)-5,6-dihydropyridine-1(2H)-carboxylate (2, 1.18 g, 3.56 mmol), 2-chloro-3-fluorophenyl boronic acid (0.621 g, 3.56 mmol), Pd(PPh3)4 (0.411 g, 0.356 mmol) and 2 M Na2CO3 (20 mL) in DME (50 mL) was heated at 80° C. for 6 h. The mixture cooled to ambient temperature, and the resulting solids were removed by filtration through a Celite pad. The filtrate was washed brine solution (4×50 mL) and concentrated under reduced pressure. The resulting residue was chromatographed over silica gel (Isco CombiFlash Rf unit, 40 g Redisep column, 0% to 80% EtOAc in hexanes) to provide tert-butyl 4-(2-chloro-3-fluorophenyl)-5,6-dihydropyridine-1(2H)-carboxylate (12) as a clear oil (0.579 g, 52%): 1H NMR (300 MHz, DMSO-d6) δ 7.43-7.31 (m, 2H), 7.16-7.10 (m, 1H), 5.81-5.72 (m, 1H), 4.03-3.93 (m, 2H), 3.53 (t, J=5.7 Hz, 2H), 2.41-2.31 (m, 2H), 1.43 (s, 9H).

Provenance & Evidence