Sodium Carbonate → tert-butyl 4-(2-chloro-5 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, 1.10 g, 3.3 mmol), 2-chloro-5-fluorophenyl boronic acid (0.58 g, 3.3 mmol), Pd(PPh3)4 (0.38 g, 0.33 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-5 fluorophenyl)-5,6-dihydropyridine-1(2H)-carboxylate (15) as a clear oil (0.57 g, 55%): 1H NMR (300 MHz, DMSO-d6) δ 7.53-7.46 (m, 1H), 7.23-7.14 (m, 2H), 5.79-5.74 (m, 1H), 4.00-3.92 (m, 2H), 3.52 (t, J=5.7 Hz, 2H), 2.40-2.32 (m, 2H), 1.43 (s, 9H).

Provenance & Evidence