Sodium Carbonate → 5-Hydroxymethyl-2-(2-oxo-1,2-dihydro-quinolin-3-yl)-indole-1-carboxylic acid tert-butyl ester

Participants

Reaction Steps

A stirred mixture of the iodoquinolinone (5-5, 10 g, 36.9 mmol, 1 equiv), the boronic acid (5-4, 7.5 g, 18.45 mmol, 0.5 equiv), tetrakis(triphenylphosphine)palladium (1.71 g, 1.48 mmol, 0.04 equiv), and lithium chloride (4.69 g, 110.7 mmol, 3 equiv) in dioxane/2M-aqueous Na2CO3 was degassed and heated at 80° C. until the boronic acid is not detected by thin layer chromatography. Additional boronic acid (0.2 equiv at a time) was added to the reaction mixture until all the iodoquinolinone (5-5) was consumed completely (1.5 equivalent of the boronic acid, 5-4, in total, was required). The reaction mixture was partitioned between ethyl acetate and saturated aqueous NaHCO3. The organic layer was washed with brine, separated, dried (MgSO4) and concentrated in vacuo. The crude oil (5-6) was dissolved in tetrahydrofuran (100 mL), transferred to the PEG bottle, treated at 0° C. with HF-pyridine (15 mL) and stirred for 1 h at ambient temperature. The reaction mixture was partitioned between ethyl acetate and saturated aqueous NaHCO3. The organic layer was washed with brine, separated, dried (MgSO4) and concentrated in vacuo. The crude solid was trituated with ethyl acetate and hexanes, collected by filtration and air-dried to afford the desired product (5-7) as a light yellow solid; 1H NMR (500 MHz, DMSO-d6) δ 12.1 (s, 1H), 8.07 (s, 1H), 8.03 (d, 1H, J=8.5 Hz), 7.74 (d, 1H, J=7.5 Hz), 7.55 (s, 1H), 7.52 (t, 1H, J=7.5 Hz), 7.35 (d, 1H, J=8.5 Hz), 7.30 (d, 1H, J=7.5 Hz), 7.22 (t, 1H, J=7.5 Hz), 6.77 (s, 1H), 5.21 (t, 1H, J=5.5 Hz), 4.60 (d, 2H, J=5.5 Hz), 1.35 (s, 9H).

Provenance & Evidence