Conformational search and spectroscopic analysis of bis-β-d-glucopyranosyl azacrown derivative. Issue 17 (26th April 2018)

• Record Type: Journal Article
• Authors: Adamiak, Marta; Porwański, Stanisław; Ignaczak, Anna
• Is Part Of: Tetrahedron. Volume 74:Issue 17(2018)
• Page Start: 2166
• Page End: 2173
• Publication Date: 2018-04-26
• Subjects: Azacrown ethers -- Saccharide derivatives -- Quantum calculations -- Drugs complexation -- NMR -- IR; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tet.2018.03.025
• Languages: English
• ISSNs: 0040-4020

Abstract

Abstract: 1, 10-N, N ′-bis-(β-d -ureidoglucopyranosyl)-4, 7, 13-trioxa-1, 10-diazacyclopentadecane is a new, recently synthesized compound, which exhibits complexation ability towards drugs. In the present study various theoretical methods, including molecular mechanics, computer simulations, semiempirical and DFT calculations, are applied to find the lowest energy conformers of this molecule in vacuo and in aqueous solution. For the most stable structures the vibrational frequencies as well as the C and H chemical shifts were computed. Along with the theoretical investigation the IR in the KBr discs and the NMR spectra in water and in pyridine were experimentally recorded. It is shown that in the lowest energy structures the two glucosyl units are placed on the same side of the diazacrown ring with their mutual orientations favoring formation of hydrogen bonds. The "open" structure, in which no such hydrogen bonds can be formed, is found to have much higher energy. The computed and measured IR spectra and NMR chemical shifts are compared and discussed in detail. The most stable structures are analyzed with respect to the possible mechanism of complexation of drugs. Graphical abstract: Highlights: Bis -β-d -glucopyranosyl azacrown derivative most stable structures in vacuo and water. Compact structure - glucose units form hydrogen bonds, minor solvent effect. Computed IR and NMR compared to experimental spectra exhibit some differences. Different conformers involved in formation of complex with aspirin.