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1 H‐ and 13 C‐NMR, FTIR, UV‐VIS, ESI‐MS, and PM5 studies as well as emission properties of a new Schiff base of gossypol with 5‐methoxytryptamine and a new hydrazone of gossypol with dansylhydrazine
Author(s) -
Przybylski Piotr,
Bejcar Grzegorz,
Huczyński Adam,
Schroeder Grzegorz,
Brzezinski Bogumił,
Bartl Franz
Publication year - 2006
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.20505
Subject(s) - chemistry , tautomer , electrospray ionization , gossypol , chloroform , glyoxal , protonation , schiff base , photochemistry , proton nmr , carbon 13 nmr , hydrogen bond , mass spectrometry , crystallography , stereochemistry , organic chemistry , molecule , chromatography , ion , biochemistry
A new Schiff base of gossypol with 5‐methoxytryptamine (GSTR) and a new hydrazone of gossypol with dansylhydrazine (GHDH) have been synthesized and studied by Fourier transform infrared (FTIR), 1 H and 13 C nuclear magnetic resonance (NMR), ultraviolet‐visible (UV‐VIS), electrospray ionization–mass spectroscopy (ESI‐MS) as well as the parametric method PM5. The spectroscopic methods have provided clear evidence that GSTR exists in chloroform solution as an enamine–enamine tautomer, whereas GHDH is present in chloroform as a N‐imine–N‐imine tautomer. The fluorescence spectra of both compounds indicate that their quantum yield of fluorescence is increased by one or two orders of magnitude compared to that of pure gossypol. The ESI‐MS spectra of the 1:1 mixtures of GSTR or GHDH with formic acid have demonstrated that both compounds exist as protonated monomers in the gas phase, whereas GHDH can also exist in a stable protonated dimeric structure. The structures of the stable tautomers are calculated and visualized using the PM5 semiempirical method. The intra‐ and intermolecular hydrogen bonds within these structures are discussed. © 2006 Wiley Periodicals, Inc. Biopolymers 82: 521–535, 2006 This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com