Tetrahydroquinazoline-substituted chromones from Diels-Alder reaction of (E)-2-styrylchromones and pyrimidine ortho-quinodimethane

The Diels-Alder reaction of (E)-2-styrylchromones with a pyrimidine ortho-quinodimethane is reported for the first time. These cycloaddition reactions afford mixtures of two regioisomeric tetrahydroquinazoline-substituted chromones in moderate to excellent global yields. Irrespective of the substituents on the 2-styrylchromones, the 2-(7-aryl-4-methoxy-2-methyl-5,6,7,8-tetrahydroquinazolin-6-yl)chromone derivatives are always the major isomers.

The Diels-Alder reaction of (E)-2-styryl chromones with a pyrimidine ortho-quinodimethane yields a mixture of two isomeric 5,6,7,8-tetrahydroquinazoline-substituted chromones.