Two Independent Intermolecular ۱D-Polymeric H-Bonds between Each Enantiomer in Octahydro-۱H-Xanthene-۱,۸(۲H)-Diones and Bis-Xanthen Analogues: Synthesis and Crystal Structure

Reaction of ۱,۳-cyclohexanedione, aldehydes, and cyanogen bromide leads to the selective formation of octahydro-۱H-xanthene-۱,۸(۲H)-diones in moderate to good yields at room temperature under basic condition. The reaction of dialdehydes such as phthalaldehyde and terphthalaldehyde gaves tetrahydrodibenzo[b,e]oxepin-۱(۲H)-one and bifunctiolalized linked bis-xanthen analogues, respectively. All structures were characterized by FT IR, ۱H and ۱۳C NMR spectroscopy and Mass analysis techniques. The structure of ۳c was analyzed by X-ray crystallography. The pKa and hydrogen bond strength (EHB) were determined in results of ≈۱۱.۷ and to ≈۵ kcal.mol-۱, respectively, via d(O•••••O) distance.

Keywords:

۱ , ۳-cyclohexanedione , Octahydro-۱H-xanthene-۱ , ۸(۲H)-dione , One-pot , Xanthene , Polymeric H-bond