3-Buten-2-one, 4-methoxy- → 6-Methyl-2-oxo-1-phenyl-1,2-dihydro-pyridine-3-carboxylic acid

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Reaction Steps

Ethyl 3-oxo-3-(phenylamino)propionate (56.8 g, 0.27 mol) and 4-methoxy-3-buten-2-one (30.2 g, 0.30 mol) were dissolved in methanol (300 mL), and 20% sodium ethoxide. (112 g, 0.33 mol) was added dropwise thereto at room temperature. After the dropwise addition, the mixture was refluxed for 8 hours under heating. The reaction mixture was cooled and then concentrated under reduced pressure, and thus obtained residue was dissolved in a mixed solution of 1,4-dioxane (200 mL) and water (200 mL). To the resultant solution, lithium hydroxide monohydrate (23.0 g, 0.55 mol) was added, and the mixture was stirred overnight at room temperature. The reaction mixture was poured into water, and washed with ethyl acetate. The aqueous layer was acidified by adding citric acid, and then extracted with chloroform. The organic layer was washed with water, dried, and concentrated, and thus obtained crystal was washed with ethyl acetate, to obtain 43.4 g of a desired product (yield: 69%).

Provenance & Evidence