Boron tribromide → 3-(1-Ethyl-4,4,6-trimethyl-2-oxo-1,2,3,4-tetrahydro-quinolin-7-yl)-4-hydroxy-benzaldehyde

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Reaction Steps

A solution of 7.05 g of Compound 1B (20.1 mmol) in 60 mL of dry dichloromethane was treated with 40 mL of 1M BBr3 in dichloromethane. The reaction flask was then equipped with a reflux condenser, nitrogen inlet and heated to reflux. After 2 hours another 20 mL of BBr3 was added and refluxing continued for an additional 2 hours. The reaction mixture was allowed to cool to room temperature. The crude reaction mixture was diluted with dichloromethane and washed with water (2×50 mL) and brine (50 ml), dried over magnesium sulfate, filtered and excess solvent removed on the rotary evaporator. The crude product Compound 1C was purified by flash chromatography (EtOAc/Hexanes; gradient 15% to 30%) to give 3.6 g (53%) of product as a white solid. MS (electrospray): mass calculated for C21H23NO3, 337.17; m/z found 338.3, [M+H]+. 1HNMR (400 MHz, CDCl3): 9.91 (s, 1H), 7.85 (dd, J=2.0, 8.5 Hz, 1H), 7.70 (d, J=1.98 Hz, 1H), 7.25 (s, 1H), 7.15 (d, J=8.4 Hz, 1H), 6.89 (s, 1H), 6.20 (s, 1H), 4.01 (q, J=7.1 Hz, 2H), 2.52 (s, 2H), 2.15 (s, 3H), 1.33 (s, 6H), 1.22 (t, J=7.09 Hz, 3H).

Provenance & Evidence