Reactions of 3-aminoisoxazolo[4,5-c]coumarin with benzoyl chloride: the first example of a preparative 1,2,4-oxadiazole–oxazole rearrangement

Depending on conditions, reaction of 3-amino-4H-chromeno[3,4-d]isoxazol-4-one with benzoyl chloride gives 4-hydroxy- and/or 4-benzoyloxy-3-(5-phenyl-1,2,4-oxadiazol-3-yl)coumarins, which are rearranged into 2-benzamido-4H-chromeno[3,4-d]oxazol-4-one by heating in DMSO.