Synthesis of 1,2-dimethoxy-1,2-di(pyridin-2-yl)-1,2-ethanediol: Crystal and molecular structure determination

摘要

The compound, 2-hydroxy-[1,2-di(pyridin-2-yl)]ethane-1-one, 1, was isolated from the reaction of 2-pyridinecarboxaldehyde and 2-pyridinemethanol at 140 degrees C without catalyst or solvent and characterized by H-1-NMR and IR spectral data. The compound 1 was treated with ethyl acetate to produce the 1,2-di(pyridin-2-yl)ethane-1,2-dione, 2. When 2 was dissolved in an excess of CH3OH, crystals of 1,2-dimethoxy-1,2-di(pyridin-2-yl)-1,2-ethanediol, 3, were obtained. The molecular and crystal structure of 3 was determined by single crystal X-ray diffraction. The compound crystallizes in the monoclinic system belonging to the P2(1) space group with a = 6.867(2) angstrom, b = 9.546(4) angstrom, c = 10.522(5) angstrom, alpha = 90 degrees, beta = 98.48(4)degrees, gamma = 90 degrees. The asymmetric unit comprises two molecules of 3. Although the di-hemiketal was obtained in crystal form, it was found to be unstable, because its IR spectrum changed after a short time, indicating that it had been converted back to the original diketone, 2. The IR showed signals at 1713, and 1690 due to nu C = O assigned to di-ketone group.