6-bromo-4,4-dimethyl-3,4-dihydroquinolin-2(1H)-one → 6-Bromo-1,2,3,4-tetrahydro-4,4-dimethylquinoline

Participants

Reaction Steps

To 23.5 ml of 1.0 M (23.5 mmol) lithium aluminum hydride in THF, heated to reflux under nitrogen, was added to solution of 4.95 g (19.48 mmol) of 4,4-dimethyl-6-bromo-2-oxo-1,2,3,4-tetrahydroquinoline (Compound 93) in 50 ml of dry THF and 100 ml of dry ether via a double-ended needle. The mixture was heated at reflux for 2 h and then cooled to room temperature. The reaction mixture was then quenched by the slow addition of 25 ml of water followed by 50 ml of 5% NaOH solution. The mixture was extracted with 2×25 ml of ether, the organic extracts were combined and washed successively with 25 ml each of water and saturated NaCl solution and then dried (MgSO4). The solvent was removed in vacuo and the residue purified by flash chromatography (silica; 15% ethyl acetate in hexanes) to give the title compound as a brown oil. PMR (CDCl3): δ 1.27 (6H, s), 1.67-1.74 (2H, m), 3.23-3.32 (2H, m), 3.90 (1H, broad s), 6.33 (1H, d, J~8.4 Hz), 7.10 (1H, dd, J~8.4 Hz, 2.3 Hz), 7.25 (1H, d, J~2.3 Hz).

Provenance & Evidence