The Acetyl Derivative of a Novel Fries Rearrangement Product

The structure of the acetyl derivative of a novel Fries rearrangement product, 8,3'-methylene[7-acetoxy-4-methyl-2H-1-benzopyran-2-one][4''-methyl-2''H-1''- pyran-2''-one(5',6':6'',5'')-2'H-1'-benzopyran-2'-one] {IUPAC name 4-methyl-7-[(4-methyl-2,8-dioxo-2H,8H-pyrano[2,3-h]chromen-9-yl)methyl]-2-oxo-2H-chromen-6-yl acetate, C₂₆H₁₈O₈}, has been determined. The result confirms the somewhat surprising formation of a biscoumarin derivative from a coumaryl ester. The planes of the two coumarin units are inclined at an angle of 74.7 (1)° and the exocyclic angles about the coumarin points of attachment to the methylene C atom show an interesting asymmetry.

-1