Cesium carbonate → Methyl 6-(tert-butoxycarbonylamino)quinoline-3-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a round bottom flask under dry nitrogen were added palladium(II) acetate (100 mg, 0.6 mmol), Xantphos (600 mg, 1 mmol), methyl 6-bromoquinoline-3-carboxylate (1.5 g, 5.64 mmol), t-butyl carbamate (0.99 g, 8.4 mmol) and cesium carbonate (3.67 g, 11.3 mmol). Dry 1,4-dioxane (30 mL) was added by syringe and the mixture was stirred at 100° C. under dry nitrogen for 4 h. The reaction mixture was cooled to room temperature, diluted with water and extracted three times with ethyl acetate. The combined extracts were washed with brine, dried over sodium sulfate, filtered and concentrated under reduced pressure. The crude mixture was purified by silica gel chromatography (hexanes to 1:1 hexanes/ethyl acetate gradient) to afford methyl 6-(tert-butoxycarbonylamino)quinoline-3-carboxylate (Int-2, 1.29 g, 76%). LC-MS: (FA) ES+ 303; 1H NMR (400 MHz, d6-DMSO) δ ppm 9.86 (s, 1H), 9.14 (d, J=2.1 Hz, 1H), 8.82 (d, J=1.9 Hz, 1H), 8.29 (d, J=2.0 Hz, 1H), 8.00 (d, J=9.1 Hz, 1H), 7.87 (dd, J=9.1, 2.4 Hz, 1H), 3.93 (s, 3H), 1.51 (s, 9H).

Provenance & Evidence