Synthesis,spectroscopic analysis and PM6 studies of a new Schiff base derived from gossypol and adamantanine

Objective To investigate the tautomeric form of the Schiff base of gossypol with adamantanine. Methods The Schiff base of gossypol with adamantanine was synthesized and identified by FT-IR,2D-NMR Spectroscopy and the PM6 semi classical calculation.Results The 1H and 13CNMR signals of the new Schiffbase were assigned.The calculated formation heat for N-enamine-N-enamine and N-imine-N-imine tautomeric forms are-1 160.00 kJ·moL-1and-1 008.319 kJ·moL-1 respectively,indicating that the former tautomer is more stable. Conclusion The Schiff base of gossypol with adamantanine exists in enamine-enamine tautomeric form,which was stabilized by the intramolecular hydrogen bonds.