Dimethylformamide → 6-Methoxy-1-methyl-3,4-dihydro-2-naphthaldehyde

Participants

Reaction Conditions

Reaction Steps

To a solution of Compound B (0.44 g, 2.5 mmole) in dry dimethylformamide (1.3 ml, 16.8 mmole) at ice cooling and stirring under argon atmosphere, phosphorus oxychloride (0.62 ml, 6.65 mmole) was added drop-by-drop in 2 minutes. The reaction mixture was stirred in an oil bath of 70-75° C. for 3 hours. After cooling in an ice bath, ice (6 g) was added, then sodium acetate (anhydrous, 3.7 g) was added, and the mixture (pH ˜6) was warmed in an oil bath at 70-75° C. for 15 minutes. After cooling, it was extracted with ether (1×10 ml and 3×5 ml), the combined organic solutions were washed with water (3×3 ml), dried (magnesium sulfate), decolorized (with activated carbon), and evaporated. The residue (0.33 g) was recrystallized from cyclohexane (2 ml) and dried over potassium hydroxide in a vacuum giving the pure product 6-Methoxy-1-methyl-3,4-dihydro-2-naphthaldehyde (Compound C, 0.22 g, 44%) as light brown crystals, mp. 70-72° C.

Provenance & Evidence