Spirolactone of Xanthene. II. Synthesis and Molecular Structure of 2′,5,7′-Trichlorospiro[benzofuran-3(2H),9′-[9H]xanthen]-2-one

Abstract

Abstract The title compound has been synthesized by the novel condensation reaction of p-chlorophenol with oxalic and sulfuric acids; its crystal and molecular structures have been determined by the single crystal X-ray diffraction method. The space group is C2/c. There are eight molecules of the title compound in the unit cell of dimensions a=21.316(9), b=17.267(4), c=9.158(6) Å, and β=94.05(5)°. The structure was solved by the direct method and refined by the block-diagonal least-squares method to a value of 0.088 for R using 1993 independent observed reflections with Fo>3σ(Fo). The molecule possesses three phenyl rings fused to spirolactone and the dihedral angles between the phenyl rings are 73.60°, 83.60°, and 22.81°.