Rearrangement of 3-aminoisoxazolo[4,5-c]coumarins into 2-aminooxazolo[4,5-c]coumarins mediated by carboxylic acid anhydrides

Abstract: Reactions of 3-amino-4H-chromeno[3,4-d]isoxazol-4-ones with acetic and trifluoroacetic anhydrides gave the corresponding acetyl derivatives, which were rearranged into 2-amino-4H-chromeno[3,4-d][1,3]oxazol-4-ones by heating in DMSO solution. [Copyright &y& Elsevier]