CP-MAS and FT-IR spectroscopic studies of new derivatives of gossypol in solid

Two hydrazones and one Schiff base of racemic gossypol have been studied by FT-IR, 13C and 15N CP-MAS spectroscopy. The spectroscopic methods have provided clear evidence that the hydrazones exist in the N-imine–N-imine tautomeric forms, whereas the Schiff base exists in the solid state as enamine–enamine tautomer. The structures of the compounds studied and the hydrogen bonds within these structures are discussed. q 2005 Elsevier B.V. All rights reserved.