| Titre : |
Synthesis and spectroscopic characterisation of the polygalloyl esters of polyols-models for gallotannins |
| Type de document : |
texte imprimé |
| Auteurs : |
H. R. Tang, Auteur ; Anthony D. Covington, Auteur ; R. A. Hancock, Auteur |
| Année de publication : |
2003 |
| Article en page(s) : |
p. 179-188 |
| Note générale : |
Bibliogr. |
| Langues : |
Anglais (eng) |
| Catégories : |
Analyse spectrale
Caractérisation
Composés organiques -- Synthèse
Esters polygalloyliques
Gallo-tanins
Polyols
|
| Index. décimale : |
675.2 Préparation du cuir naturel. Tannage |
| Résumé : |
Hydrolysable gallotannins are naturally occurring polygalloyl esters of polyols (e.g., glucose) and are widespread in the plant kingdom. A totally new synthesis is described here for polygalloyl (3,4,5-trihydroxybenzoyl) esters of polyols as structural models for gallotannins, so that the structure-function relationships of this group of phytochemicals can be studied. The new synthesis consists of two steps, condensation of trimethoxybenzoyl chloride with a polyol and demethylation with anhydrous aluminium chloride/thiol. Compared to methods already reported, the new synthesis shortens the total reaction time by up to 30 times and gives high yields. Six polygalloyl esters of polyols were synthesised: di-galloyl-ethylene glycol (DGE), tri-galloyl-glycerol (TGG), tetra-galloyl-meso-erythritol (TGE), penta-galloyl-adonitol (PGA), ß-penta-galloyl-D-glucose (PGG) and hexa-galloyl-dulcitol (HGD). Amongst them, TGE, PGA and HGD are prepared for the first time. The polyphenols and
their permethylated derivatives were characterised using a combination of NMR and mass spectroscopic techniques. The effects of galloylation on the NMR properties of polyols are also discussed. |
| Note de contenu : |
- EXPERIMENTAL :
- Materials and methods
- Preparation of poly-(3,4,5-trimethoxybenzoyl)-polyols
- Demethylation of permethylated polygalloyl polyols
- RESULTS AND DISCUSSION :
- Synthesis of polygalloyl polyols
- Spectroscopic characterisation of permethylated polygalloyl esters
- Spectroscopic characterisation of polygalloyl polyols
- Table 1 : Data for permethylated polygalloyl esters 2a-7a
- Table 2 : H NMR data for permethylated polygalloyl esters 2a - 7a*
- Table 3 : 13C NMR data for permethylated polygalloyl esters 2a - 7a*
- Table 4 : Data for polygalloyl esters of polyols 2 - 7
- Table 5 : H NMR data for polygalloyl esters (2-7)
- Table 6 : 13C NMR Data for polygalloyl esters 2-7 |
| En ligne : |
https://drive.google.com/file/d/1dJsl5exn-XbLBsFXulD7COfgg5qdqqkQ/view?usp=drive [...] |
| Format de la ressource électronique : |
Pdf |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39743 |
in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 87, N° 5 (09-10/2003) . - p. 179-188
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Synthesis and spectroscopic characterisation of the polygalloyl esters of polyols-models for gallotannins in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 87, N° 5 (09-10/2003)
