Synthesis of 2,2′-diaminobischromones using a modified procedure for the rearrangement of 5-(2-hydroxyphenyl)isoxazole to 2-aminochromone

A modified procedure for the rearrangement of 5-(2-hydroxyphenyl)isoxazoles 6a-e to 2-aminochromones 8a-e was developed and this procedure was utilised in the synthesis of hitherto unreported bischromones 3a-c. The isoxazoles 6a-e were prepared regioselectively from aminovinylketones 5.