Yield:-

Reaction Conditions:

Stage #1: 3,4-dihydro-4,4,6-trimethyl-2(1H)-quinolinonewith dimethylsulfide borane complex in toluene at 0 - 100;
Stage #2: with sodium carbonate in water;toluene at 20; for 0.5 h;

Steps:

25.2

To a solution of 4,4,6-trimethyl-3,4-dihydro-l H-quinolin-2-one (98, 3.86 g, 20.4 mmol) in 150 mL of toluene, borane-dimethyl sulfide complex (3.6 mL, 41.0 mmol) was added slowly at 0 ⁰C. The reaction mixture was stirred at 0 ⁰C for 15 minutes and then stirred at 100 ⁰C for 2 hours. The reaction mixture was cooled down and poured into 150 mL of aqueous 10% sodium carbonate solution. The mixture was stirred at room temperature for 30 minutes and the organic layer was collected. The aquous layer was extracted with 2 x 60 mL of ethyl acetate and the organic layers were combined and dried over magnesium sulfate, filtered and the filtrate concentrated under vacuum. The residue was purified by silica gel chromatography to provide the desired compound as a light brown liquid (99, 2.3 g) ¹H NMR was consistent with the compound structure.

References:

WO2010/129467,2010,A1 Location in patent:Page/Page column 86