Synthesis and Structural Characterization of N-propyl-7-oxa-bicyclo[2,2,1]hept-5-ene-2,3-dicarboximide

Abstract

The compound N-propyl-7-oxa-bicyclo[2,2,1]hept-5-ene-2,3-dicarboximide (C₁₁H₁₃NO₃, M_r = 207.22) was synthesized and characterized by elemental analysis, ¹H NMR spectra, IR spectra and single crystal X-ray diffraction. The crystal belongs to monoclinic, space group P21/c, with a = 9.7040(10), b = 8.9501(8), c = 15.4719(16) Å, b = 128.845 (2)º, V = 1046.58(18) ų, Z = 4, D_c = 1.315 g/cm³, l = 0.71073 Å, μ(MoK_a) = 0.096 mm^-1, F(000) = 736. The final refinement gave R = 0.0434, wR(F²) = 0.0998 for 5.254 observed reflections with I > 2s(I). The structure of this compound comprises a racemic mixture of chiral molecules containing four stereogenic centres. X-ray diffraction analysis reveals that the cyclohexene ring tends towards a boat conformation, the tetrahydrofuran ring and the dihydrofuran ring adopt envelope conformation. The plan C3/C4/C5/C8 and the plan C5/C6/C7/C8 form dihedral angles of 69.1 (2)º and 64.2 (2)º, respectively with the pyrrole ring. The crystal structure is stabilized by C-H...O hydrogen bonds.