X-Ray analysis of (Z)-2-p-methoxyphenylmethylenebenzofuran-3(2H)-one

Abstract

The X-ray structure of the title compound (1; R = H, Ar =p-MeO·C₆H₄) establishes that aurones are planar molecules and confirms the (Z)-configuration assigned to naturally occurring and synthetic aurones from a correlation of dipole-moment measurements with their characteristic i.r. spectra. Crystals are monoclinic, space group P2₁/c with a= 12.005(1), b= 3.916(1), c= 27.184(2)Å, β= 106.4°. The structure was solved from diffractometer data by direct methods and refined by block diagonal least-squares methods to R 4.3 % for 1875 observed reflections.