Pyridine → isoquinolin-1-yl 2-oxo-2H-1-benzopyran-3-carboxylate

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Reaction Steps

1.0 g of the commercially available 2-oxo-2H-1-benzopyran-3-carboxylic acid and 10 ml of thionyl chloride were refluxed for 3 h. The resulting solution was evaporated under reduced pressure. The residue was suspended in 10 ml anhydrous toluene. The solvent was eliminated by distillation under reduced pressure. The two last steps were repeated twice. The residue was dispersed in 10 ml dioxane. To this suspension were added 1-hydroxyquinoleine (1.1 éq.) and anhydrous pyridine (1.1 eq.). After 90 min stirring at room temperature, the solvent was removed by distillation under reduced pressure. The residue was solubilized in chloroform and the organic phase was washed three times with HCl 0.1N, then dried over MgSO4. The solvent was evaporated under reduced pressure and the residue obtained was recrystallized in ethyl acetate.

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