p-Toluenesulfonic acid → 2-(4-Morpholinyl)-4H-1-benzopyran-4-one

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Reaction Steps

Part B: Tosic acid (0.4 g, 2 mmol) is added to a solution of 2-mercapto-4H-1-benzopyran-4-one (3.56 g, 20 mmol) and morpholine (2.44 g, 2.44ml, 28 mmol) in benzene (400ml). After refluxing for 4 hours, the reaction mixture is transferred to a separatory funnel containing EtOAc and water. Extracting with EtOAc (2×), washing with combined organic layers with water and brine, and filtering through sodium sulfate yields 4.56 of crude material after evaporation of the solvent. Flash chromatography over silica gel (300 g, 2.5% MeOH/CHCl3, 50 ml fractions) yields 2.07 g of 2-(4-Morpholinyl)-4H-1-benzopyran-4-one (44.8%, fractions 22-32). Mp 160°-1° C.

Provenance & Evidence