Methanesulfonic Acid → 6-methoxy-3,4-dihydroisoquinolin-1(2H)-one

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Reaction Steps

Phosphorous pentoxide (1.0 g, 7.1 mmol) is added all at once to methanesulfonic acid (10 g, 104.1 mmol) and stirred for 3 hours at room temperature. 5-Methoxy-1-indanone oxime (100 mg, 0.53 mmol) is added in portions, with each portion allowed to dissolve completely before the next is added. The stirred reaction mixture is heated at 100° for 1.5 hours. The reaction is quenched by the addition of saturated sodium bicarbonate (10 ml) and extracted with 3×5 ml dichloromethane. The combined organic layers are dried over magnesium sulfate and concentrated in vacuo to yield the 6-methoxy-1-oxo-1,2,3,4-tetrahydroisoquinoline. Treatment with boron tribromide (see example 1) yields 6-hydroxy-1-oxo-1,2,3,4-tetrahydroisoquinoline.

Provenance & Evidence