Ethyl Acetate → Tert-butyl 4-(4-aminophenyl)-5,6-dihydropyridine-1(2H)-carboxylate

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Reaction Conditions

Reaction Steps

To a mixture of 4-trifluoromethanesulfonyloxy-3,6-dihydro-2H-pyridine-1-carboxylic acid tert-butyl ester (Synthesis, 993, (1991), 7.4 g, 22 mmol), 4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-phenylamine (4.0 g, 18 mmol) and Pd(PPh3)4 (2.3 g, 2.0 mmol) in 160 mL of toluene and 80 mL of absolute ethanol under Ar was added 2.0 M aq Na2CO3 solution (80 mL, 160 mmol). The resulting mixture was stirred at 80° C. for 3 h and then cooled to RT. After adding 600 mL of EtOAc, the mixture was washed with 1 M NaOH (250 mL), H2O (2×250 mL), brine (300 mL) and dried (Na2SO4). Removal of the solvent under reduced pressure followed by flash chromatography of the residue on silica gel (20% EtOAc/hexane) gave 3.20 g (63%) of the title compound as a hard yellow foam: Mass spectrum (ESI, m/z): Calcd. for C16H22N2O2, 275.2 (M+H), found 275.1.

Provenance & Evidence