Study of supramolecular inclusion complexes of pseudoephedrine, lupinine, anabasine and cytisine with β-cyclodextrin by NMR spectroscopy

Abstract

The 1H, 13C and DEPT one-dimensional NMR and two-dimensional spectroscopy methods COSY (1H-1H), HMQC (1H-13C) and TOCSY (1H-1H) were used to study the alkaloids pseudoephedrine, lupinine, anabasine and cytisine and their supramolecular inclusion complexes with cyclic polysaccharide β-cyclodextrin. The proton-proton correlation patterns are presented through three bonds and the proton-carbon correlation patterns through one bond, namely COSY (1H-1H) and HMQC (1H-13C) in the molecules of the alkaloids under study. The use of the capabilities of two-dimensional spectroscopy COSY (1H-1H), HMQC (1H-13C) and TOCSY (1H-1H) to identify the studied alkaloids allowed us to correctly and unambiguously identify the structure of substrates of the supramolecular self-assembly with a cyclic polysaccharide receptor. Homonuclear and heteronuclear correlation NMR COSY (1H-1H) and HMQC (1H-13C) is also used to identify and confirm the structure and structure of the cyclic polysaccharide β-cyclodextrin. The chemical shifts of the aliphatic and hydroxyl protons of the inner and outer surfaces of the receptor were determined. A comparative analysis of the 1H and 13C NMR spectra of pseudoephedrine, lupine, anabasine and cytisine, β-cyclodextrin and their supramolecular inclusion complexes was carried out. Changes in the chemical shifts of 1H and 13C nucleus of pseudoephedrine, lupinine, anabasine, and cytisine, and β-cyclodextrin in inclusion complexes were determined. The proton integral intensities of the substrate and receptor in the 1H NMR spectra determined that the supramolecular interaction of the studied pseudoephedrine, lupinine, anabasine and cytisine with β-cyclodextrin is accompanied by the entry of hydrophobic fragments of 1 substrate molecule into the inner cavity 1 of the receptor molecule.