Syntheses and Crystal Structures of Two Novel Spiro Compounds Containing 1,5-Dioxaspiro[5.5]undecane-2,4-dione

Two novel spiro compounds, 3-benzylidene-1,5-dioxaspiro[5.5]undecane-2,4-dione 1 and 3-(2-fluorobenzylidene)-1,5-dioxaspiro[5.5]undecane-2,4-dione 2, have been synthesized and characterized by X-ray single-crystal diffraction, IR and elemental analysis. Compound 1 belongs to the monoclinic system, space group P21/n with a = 12.326(3), b = 5.6420(11), c = 20.089(4) (A), β =101.79(3)°, C16H16O4, Mr = 272.29, V = 1367.7(5) (A)3, Z = 4, Dc = 1.322g/cm3, F(000) = 576,μ(MoKα) = 0.095 mm-1, the final R= 0.0420 and wR = 0.1159. Compound 2 is of monoclinic system,space group P21/n with a = 12.283(3), b = 5.6367(11), c = 20.055(4) (A), β = 102.00(3)°, C16H15FO4,Mr = 290.28, V= 1358.2(5) (A)3, Z = 4, Dc= 1.420 g/cm3, F(000) = 608, μ(MoKα) = 0.110 mm-1, the final R = 0.0353 and wR = 0.0860.