Of -patchoulol

Scheme 23.14 Regioselective biohydroxylation of patchoulol and the following chemical steps to produce norpatchoulenol according to [207]...

A process for the production of the latter compound, via the microbial 10-hydroxylation of patchoulol (203) and subsequent oxidation of the 10-hydroxypatchoulol (204) was published [151]. From the 350 microorganisms screened, four strains of Pithomyces species carried out regio-selective hydroxylation of patchoulol to 10-hydroxypatchoulol Pithomyces sp. NRJ201 and P. chartarum NRJ210, isolated from soil situated in the neighbourhood of Kamakura, Japan, the most important ones. A method was developed by which 10-hydroxypatchoulol was obtained in 25 to 45% yields in 1- to 5-litre fermentation jars at 2 to 4 g of patchoulol per litre and isolated as pure material in 30% yields. The... 

Fig. (41). Regioselective 10-hydroxylation of patchoulol by Pithomyces sp. and subsequent chemical conversion to nor-patchoulenol (after [151,152])...

A further study on the oxidation of terpenoid compounds by mammalian systems (c/. p. 62) has shown that patchoulol (298) is oxidized by rabbits to give a mixture of diol (299) and hydroxy-acid (300).129 Subsequent oxidative decarboxylation of (300) provided norpatchoulenol (301), the major odour carrier of patchouli oil. It has been suggested that a similar oxidative transformation of patchoulol occurs during the biosynthesis of norpatchoulenol in the plant.129 Cedrol (72) has also been oxidized by rabbits (c/. p. 62) and it is interesting to note that the hydroxylated products are... 

With other fungi various interesting transformation products of patchoulol are found hydroxylation occurs not only at the 10-position, but also at secondary and tertiary carbon atoms. Depending on the fungi employed, these alternate compounds can be the major transformation... 

Treatment of patchoulol (174 Scheme 62), an olfactive component of patchouli oil, with LTA gives rise to a mixture from which the almost pure ketone (175) is distilled. Thomas has postulated a free car-benium ion mechanism, but this reaction may be a legiospecific fragmentation facilitated by the fact that the proton on C(S) is oriented antiperiplanar to the C(l)- bond. 

Further studies on the chemistry of patchoulol (431) have shown that treatment with Pb(OAc)4 provides a 1 2 2 mixture of (432), (433), and (434). The subsequent conversion of (433) into a-bulnesene (436) was also accomplished by... 

Fig. 21.7. Biosynthesis of patchoulol (Cane, 1990 modified and used with permission of the copyright owner. Copyright 1990, American Chemical Society, Washington, DC).

Croteau et al., 1987). Furthermore, studies with [12,13- C 6- H]famesyl pyrophosphate as a precursor indicate that deprotonation-protonation steps to form bound ole-finic intermediates in the biosynthesis of patchoulol do not occur, providing support for a hydride shift mechanism (Croteau et al, 1987). Patchoulol synthase had a molecular weight of 80,000 and consisted of two identical subunits of 40,000. 

FIGURE 9.31 Proposed metabolism of patchoulol in rabbits and dogs. (Adapted from Bang, L. et al.. Tetrahedron Lett., 26, 2211,1975 Ishida, T., Chem. Biodivers., 2, 569, 2005.)... 

Bang, L., G. Ourisson, and P. Teisseire, 1975. Hydroxylation of patchoulol by rabbits. Hemi-synthesis of nor-patchoulenol, the odour carrier of patchouli oil. Tetrahedron 16 2211-2214. 

Figure 9 Production of hydroxylated metabolites of patchoulol by various fungal strains.

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