Potassium Carbonate → tert-Butyl 4-(4-(((benzyloxy)carbonyl)amino)-3-ethylphenyl)-5,6-dihydropyridine-1(2H)-carboxylate

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Reaction Steps

Potassium carbonate (215 mg, 1.55 mmol) the tert-butyl 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-5,6-dihydropyridine-1(2H)-carboxylate (I37) (160 mg, 0.517 mmol), benzyl (4-bromo-2-ethylphenyl)carbamate (I34) (182 mg, 0.543 mmol), PdCl2(dppf)-DCM solvate (22 mg, 5 mol %) and DMF (5 mL) were loaded into a Schlenk tube, and degassed with 3× vacuum/nitrogen cycles. The mixture was brought to 80° C. under nitrogen then after 18 hours cooled and poured into water (100 mL). DCM (75 mL) and brine (50 mL) were added, the aqueous phase was washed with further DCM (2×75 mL), and the combined DCM extracts washed with brine, dried and evaporated. Chromatography (40 g silica cartridge, 0-80% ethyl acetate/petroleum benzine 40-60° C.) gave the title compound (I39) (129 mg, 57% yield) as a colourless oil; 1H NMR (400 MHz, CDCl3) δ 7.77 (s, 1H), 7.45-7.31 (m, 5H), 7.22 (dd, J=8.5, 2.1 Hz, 1H), 7.18 (d, J=2.1 Hz, 1H), 6.48 (s, 1H), 5.99 (s, 1H), 5.21 (s, 2H), 4.06 (d, J=2.5 Hz, 2H), 3.63 (t, J=5.7 Hz, 2H), 2.58 (q, J=7.6 Hz, 2H), 2.50 (s, 2H), 1.49 (s, 9H), 1.22 (t, J=7.6 Hz, 3H). LCMS Method C: rt 6.67 min; m/z 337.1 [M-Boc+2H]+, 381.1 [M-tBu+2H]+.

Provenance & Evidence