Methanol → 3-(1-oxo-7-(trifluoromethyl)-3,4-dihydroisoquinolin-2(1H)-yl) isonicotinaldehyde

Participants

Reaction Steps

p-Toluene sulphonic acid (PTSA) (4.3 g, 23.093 mmol) was added to a stirred solution of 2-(4-dimethoxymethyl-pyridin-3-yl)-7-trifluoromethyl-3,4-dihydro-2H-isoquinolin-1-one (I-53b: 900 mg, 2.4568 mmol) in acetone (30 mL) and water (30 mL) and resulting reaction mixture was stirred for 48 hours at room temperature. The reaction mass was distilled under vacuum and the crude residue was dissolved in methanol (20 mL). This was followed by the addition of 2 N HCl (10 mL) and refluxed the resulting reaction mass for 3 hours. The reaction was monitored by TLC (10% methanol in CHCl3). The reaction mixture was cooled to room temperature and concentrated under reduced pressure. The crude residue was diluted with ice, basified using saturated NaHCO3 solution and extracted using CHCl3. The organic layer was washed with water, brine solution, dried over Na2SO4 and concentrated under reduced pressure. Purification by column chromatography on silica gel (2% methanol in CHCl3) afforded 110 mg of the product (14% yield).

Provenance & Evidence