No abstract

The natural abundance (2)H NMR characterization of raspberry ketone 1 extracted from himalayan Taxus baccata and of the accompanying (R) carbinol 2 is performed and compared with that of samples of 1 obtained from 2 by oxidation with Candida boidinii and CrO(3), respectively. The determination of the delta((13)C) and/or delta((18)O) values of the above extractive products and of benzoic acid (6) and 4-butylphenol (10), obtained from natural of synthetic 1, and of 4-phenylbutan-2-ol (8), prepared from extractive 2, allows a description of the labeling pattern of this set of products. A graph of (D/H)(3)/(D/H)(2) vs (D/H)(5)/(D/H)(4) (Figure 3) of the presently examined samples and of those previously characterized in the laboratory, including three commercial samples sold as natural, defines three areas, containing (a) the material of botanical origin and that produced from extractive 2 by biooxidation, (b) those produced by bioreduction of the unsaturated ketone 3, and (c) the synthetic samples.

In growing cultures of the fungus Beauveria bassiana (ATCC 7159) the incubation of 4-(4′-hydroxyphenyl)but-3-en-2-one (p-hydroxybenzylidenacetone, 3), of 4-(4′-hydroxyphenyl)butan-2-one (raspberry ketone, 1), and of the S and R,S forms of 4-(4′-hydroxyphenyl)butan-2-ol (2) yields 2-(4′-hydroxyphenyl)ethanol (tyrosol, 4) as a final product. The experiments support the view that the actual substrate for the Baeyer-Villiger-type degradation is raspberry ketone (1) and that there is a kinetic preference in the microbial enzymatic system for the oxidation to 1 of the S form of the 4-(4′-hydroxyphenyl)butan-2-ol (2).

No abstract

No abstract