Water → 4-(8-methoxy-1-(1-methoxypropan-2-yl)-2-(tetrahydro-2H-pyran-4-yl)-1H-imidazo[4,5-c]quinolin-7-yl)-3,5-dimethylisoxazole

Participants

Reaction Steps

A mixture of N-(7-(3,5-dimethylisoxazol-4-yl)-6-methoxy-4-((1-methoxypropan-2-yl)amino)quinolin-3-yl)tetrahydro-2H-pyran-4-carboxamide (for a preparation see Intermediate 3) (11.95 g, 25.5 mmol) and p-toluenesulfonic acid (1.2 g, 25.5 mmol) in toluene (250 ml) was heated under nitrogen at reflux using a Dean-Stark apparatus for 3 days. Further p-toluenesulfonic acid (0.2 g, 4.3 mmol) was added and heating continued overnight. Water (750 ml) was added, and the mixture basified to pH 8 using saturated aqueous sodium hydrogen carbonate solution. The aqueous was extracted with ethyl acetate (3×750 ml), the organic layers combined, dried (hydrophobic frit) and evaporated under reduced pressure. The residual solid was triturated in ether (˜200 ml), sonicated briefly. The majority of the solid appeared to be a fine powder. The fine powder suspended in the ether was decanted, the solid isolated by filtration, and dried in a vacuum oven to give crude 4-(8-methoxy-1-(1-methoxypropan-2-yl)-2-(tetrahydro-2H-pyran-4-yl)-1H-imidazo[4,5-c]quinolin-7-yl)-3,5-dimethylisoxazole (6.3 g). This material was triturated in ether (˜100 ml), sonicated briefly, and stood overnight at room temperature. The solid was isolated by filtration and dried in a vacuum oven 4-(8-methoxy-1-(1-methoxypropan-2-yl)-2-(tetrahydro-2H-pyran-4-yl)-1H-imidazo[4,5-c]quinolin-7-yl)-3,5-dimethylisoxazole (4.9 g, 10.88 mmol, 42.6% yield).

Provenance & Evidence