p-Toluenesulfonic acid → 3,4-Dihydro-2,6-naphthyridin-1(2H)-one

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Reaction Steps

2-(4-Methoxybenzyl)-3,4-dihydro-2,6-naphthyridin-1(2H)-one (I-67g: 300 mg, 1.119 mmol) was reacted with p-toluene sulfonic acid (851 mg, 4.476 mmol) and toluene (10 mL) at 110° C. for 4 hours. The reaction mass was concentrated under reduced pressure, neutralized with 1N HCl solution to pH 7 and extracted using DCM. The organic layer was dried over anhydrous Na2SO4 and concentrated under reduced pressure to afford the crude product. Purification by column chromatography on silica gel (2% methanol in CHCl3) afforded 45 mg of the product (27.10% yield).

Provenance & Evidence