Facile Preparation of 1,2-Diols from Chalcones: An NMR Spectroscopy and X-Ray Crystallography Study

Structures of 2-(naphthalen-2-ylmethyl)-2,3-dihydro-1H-indene-1,2-diol (C20H18O2), compound 1 and 1-(3,4-dimethoxyphenyl)-3-methoxy-3-(4-nitrophenyl)propane-1,2-diol chloroform (C18H21NO7·CHCl3) compound 2 were established by spectral and X-ray diffraction studies. Compound 1 crystallizes in the orthorhombic space group P212121 with unit cell parameters a = 5.2177 (6), b = 13.903 (2), c = 21.121 (2) A, Z = 4. Compound 2 crystallizes in the triclinic space group P-1 with unit cell parameters a = 9.238 (1), b = 9.879 (1), c = 12.636 (1) A, α = 102.004 (1), β = 92.356 (1), γ = 90.779 (1)o, Z = 2. These two new molecules arise from a facile preparation of 1,2-diols from chalcones and have been fully characterized. Based on the crystallographic information obtained for compound 1, the relative configuration for the chiral centers is 1S and 2S. In structure 1, both hydroxyl groups adopt an anti-conformation with a torsion angle O1-C1-C2-O2 value of 93.1 (2)o [in molecule 2, both hydroxyl groups adopt a trans-conformation with a torsion angle O1-C1-C2-O2 value of -171.0 (2)。]. In both structures, the molecules in the crystal are linked by intermolecular hydrogen bonds O-H···O and C-H···O interactions and adjacent molecules are interconnected by intermolecular weak C-H···π and C-H···Cl interactions which give additional support to molecular packing stability.