Characterization of polyphenols from plant materials through their silylation and 29Si NMR spectroscopy-line assignment through 29Si, 13C spin-spin couplings.
The lines in (29)Si NMR spectra of silylated polyphenols and some other compounds are difficult to assign owing to the absence of couplings with protons outside the silyl group. The assignment can be derived through small (n)J((29)Si, (13)C) couplings (n > 1). Using a previously described method for measurements of these couplings, the assignment procedure is demonstrated here on three examples of trimethylsilylated phenols: 7-hydroxyflavone, ferulic acid, and quercetin. In some cases the procedure can be used to identify carbon atoms to which the siloxy groups are attached.
Schraml
Jan
J
Institute of Chemical Process Fundamentals, Academy of Sciences of the Czech Republic, Rozvojová 135, 16502, Prague 6, Czech Republic. schraml@icpf.cas.cz
Blechta
Vratislav
V
Sýkora
Jan
J
Soukupová
Ludmila
L
Curínová
Petra
P
Pronek
David
D
Lachman
Jaromír
J
D002247:Carbon Isotopes; D005419:Flavonoids / Q000138:chemical synthesis / Q000737:chemistry*; D007554:Isotopes; D009682:Magnetic Resonance Spectroscopy / Q000379:methods* / Q000592:standards*; D015394:Molecular Structure; D010636:Phenols / Q000138:chemical synthesis / Q000737:chemistry*; D010944:Plants / Q000737:chemistry; D059808:Polyphenols; D012015:Reference Standards; D012825:Silicon / Q000737:chemistry*
D002247:Carbon Isotopes; D005419:Flavonoids; D007554:Isotopes; D010636:Phenols; D059808:Polyphenols; D012825:Silicon