Direct access to novel chromeno-pyrimidine-N-oxides via tandem base catalyzed double nucleophilic addition/dehydration reaction

A facile protocol for direct access to chromeno-pyrimidine-N-oxides is reported by the reaction of 4-chloro-3-formylcoumarin and aromatic carboximide oximes via tandem double nucleophilic addition and dehydration reactions. The one-pot reaction serves as an alternative protocol for achieving regioselective pyrimidine mono-N-oxide products as pure precipitates in good to excellent yields. The structure of the product was confirmed by X-ray analysis.