A. De Bruyn

Iridoids : The structure elucidation of specionin based on chemical evidence and 1H NMR analysis

Abstract The iridoid specionin is an effective antifeedant against the Eastern spruce budworm. Previous synthetic work has shown that the proposed structure was incorrect. Presently the total synthesis of the revised structure 2C is described. The structure elucidation, with special emphasis on the anomeric C-3 configuration, is based on chemical evidence and 1H NMR analysis.

On the liquid chromatography and identification of the flavonoids, present in the “sumach tannic acid” extracted fromRhus coriaria

SummaryThe leaves ofRhus coriaria contain about 15–20% polyphenolic compounds. These are mostly hydrolysable tannins, with a central glucose unit, to which several gallic acid rests are bound depsidically. 5 to 10% of the total polyphenolic fraction however, consists of condensed tannins or flavonoids. This work studies the identity and the liquid chromatographic behaviour of these flavonoids. The presence of the dimeric flavonoids agathisflavone, amenthoflavone and hinokiflavone is proved. A new dimeric flavanoid (Sumaflavone) is tentatively identified.

NMR conformational study of cinnamaldehyde-brines

Abstract The configuration and conformation of cinnamaldehyde anils have been deduced from their NMR spectra on the basis of INDOR-assisted analysis of the complex patterns, and of nuclear Overhauser experiments and solvent-effect studies.

Regioselectivity in the Chemical and Enzymatic Reactions Between Glutathione and Phenylglycidyl Ether

Abstract In the chemical reaction of phenylglycidyl ether with glutathione, NMR analysis showed that the major product of nucleophilic attack of the thiol group of glutathione was at the least substituted carbon of the epoxide yielding the normal product. An analytical reversed phase HPLC system indicated that this reaction was regioselective with a ratio of 92-8 for the normal vs the abnormal product (attack at the more substituted epoxide carbon). This HPLC method shows promise for following the glutathione transferase and hydratase detoxification of the phenylglycidyl ethers. The S-9 rat liver homogenate detoxification of the phenylglycidyl ether per se was regiospecific yielding only the normal main reaction product of the chemical reaction and a minor amount of phenoxy-propanediol.