DFT study of the per-6-amino-β-cyclodextrin as catalyst in synthesis of 2-aryl-2,3-dihydro-4-quinolones.

The synthesis of 2-aryl-2,3-dihydro-4-quinolones in the presence of per-6-amino-β-cyclodextrin (per-6-ABCD) as catalyst can improve selectivity and yield. The interaction between per-6-ABCD and benzaldehyde or o-aminoacetophenone plays an important role in this reaction. This paper studies the complexes of per-6-ABCD with benzaldehyde and o-aminoacetophenone using density functional theory (DFT) method. The reaction process is investigated by studying the energy of the reactants and the product. Hydrogen bonds are researched on the basis of natural bonding orbital (NBO) analysis, the results propose the donor-acceptor interactions of complex. The Mulliken charge and frontier orbital are employed for revealing the charge distribution. In addition, (13)C nuclear magnetic resonance ((13)CNMR) spectroscopy shows that the carbon atom on the aldehyde group for benzaldehyde, carbonyl group and the carbon atom connected with carbonyl group for o-aminoacetophenone are apparently activated in the cavity of per-6-ABCD. The probable catalytic mechanism of per-6-ABCD is discussed in terms of the calculated parameters.