p-Toluenesulfonic acid → 3-methoxy-1,7-naphthyridin-8(7H)-one

Participants

Reaction Steps

To a mixture of 3-(2,2-dimethoxyethyl)-5-methoxypicolinamide (6.74 g, 28.1 mmol) in toluene (112 ml) was added 4-methylbenzene sulfonic acid (monohydrate; 0.534 g, 2.81 mmol). The reaction mixture was heated to reflux for 20 h. The reaction mixture was cooled to rt and concentrated in vacuo to a volume of ca. 15 mL. The residue was triturated with heptanes and filtered to afford 3-methoxy-1,7-naphthyridin-8(7H)-one (4.53 g, 25.7 mmol, 92% yield) as a crude, tan solid that was advanced without further purification. Crude LCMS showed complete conversion to product MS m/z=177.1 [M+H]

Provenance & Evidence