Structural elucidation of Pogostone and its dimers-two novel diastereomers combined with X-ray diffraction and spectroscopy

Two new dimers of Pogostone were prepared simultaneously when synthesizing Pogostone. Their molecular structures were elucidated on the basis of spectral interpretation, including FT-IR, 1H and 13C NMR, homo-nuclear correlation (COSY), and hetero-nuclear correlation (HMQC and HMBC) together with single crystal X-ray diffraction. Compound 1 crystallized in the orthorhombic P bc n space group with the crystal cell parameters a = 11.24391(16) Å, b = 17.7313(3) Å, c = 22.6331(4) Å, V = 4512.34(12) Å3 and Z = 8. Compound 2 crystallized in the monoclinic P 21/c space group with the crystal cell parameters a = 15.0390(4) Å, b = 11.3591(3) Å, c = 13.1370(3) Å, β = 94.167(2)°, V = 2238.25(10) Å3 and Z = 4. The X-ray results demonstrated there solely existed classic H-bond intramolecular rather than intermolecular interactions in the molecules of the two compounds. Furthermore, regarding the R configuration (compound 1), two pyranone rings were approximately perpendicular to each other (100.614°), whereas for the S configuration (compound 2), two pyrone rings were almost paralleled (7.143°). It had obvious influence on the symmetry of molecule and great different spatial structure and the packing mode.