1,4-Dioxane → 4-Chloro-7-oxo-6,7-dihydro-1H-pyrimido[5,4-b][1,4]oxazine-2-carbaldehyde

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Reaction Steps

To a solution of 4-chloro-2-[(E)-2-phenylethenyl]-6H-pyrimido[5,4-b][1,4]oxazin-7(8H)-one (0.45 g, 1.16 mmol) in 1,4-dioxane (25 mL) and water (10 mL) was added NaIO4 (1.26 g, 4.4 mmol) along with a catalytic amount of OsO4 (0.36 mL, 4 wt. % in water). The resulting mixture was stirred at room temperature for 5 h. The solvent was evaporated under reduced pressure and the residue was extracted with 10% methanol in DCM (3×50 ml). The organic extracts were combined, dried over anhydrous MgSO4, filtered and concentrated under reduced pressure to give a solid which was purified by column chromatography (silica gel) with a 0-10% methanol in DCM gradient to give the desired product as light yellow solid (0.28 g, 84%).

Provenance & Evidence