Of P-turmerone

Separation and purification of three turmerones, e.g. ar-turmerone, a- and P-turmerone, from turmeric oil extracted by supercritical carbon dioxide gave 71% purify by weight. Subsequently, purification using a normal-phase silica gel 60 column could separate and purify three major turmerones with 86% purify by weight of ar-turmerone and 81% purity by weight of a- and P-turmerone. These were identified by liquid-solid chromatography, NMR qualification and HPLC quantification, respectively (Li-Hsun Chang et al., 2006). 

The dithioacetal is hydrolysed (mechanism like that on p. 1255), silver and cadmium being instead of mercury (not much gain in environmental friendliness there ), and the double be -moves into conjugation with the resulting ketone to complete the synthesis of ar-turmerone cart out at Caen by A. Thuillier and group, /. Org. Chem., 1979, 44, 2807. 

The possibility of conversion of the dithioacctal into the corresponding ketone without reconjugation of the double bond is a noteworthy j feature of this synthetic scheme. The syntheses of iso-ar-turmerone and isoartemisia ketone mentioned above proceeded similarly via a carbophilic pathway. In the latter case a p-ethylenic dithioester was not isomerized during the following overall sequence carbophilic addition-methylation-dithioacetalization [343]. ... 

Rupe et al. (1934) could identify two major ketonic sesquiterpenes - ar-turmerone and turmerone (C15H20O, C15H220) - responsible for the aroma of turmeric. In addition, p-cymene, P-sesquiphellandrene and sesquiterpene alcohols have also been reported (Malingre, 1975). 

Rupe, H., Clar, G., Pfau, A.St and Planner, P. (1 934) Volatile plant constituents. II. Turmerone, the aromatic principle of turmeric oils (in German). Idelvetica Chimica Acta 17, 372. 

The sequence has been used for synthesis of natural (+)-ar-turmerone (10), an aromatic sesquiterpene. Reaction of 3 (R = CH3) with p-tolyllithium followed by hydrolysis resulted in 8 in 98.8% enantiomeric purity, although in rather low yield ( 25%). The acid was converted into 10 in essentially 100% ee. ... 

More recently, Rousseau and Blanco reacted 3-methylbut-2-enoyl chloride with a number of silyl ketene acetals to produce -Yid-ethylenic P-keto esters, with yields in the range 62-80% neither but-2-enoyl chloride nor propenoyl chloride reacted under these conditions. They employed this reaction in a new synthesis of ( )-turmerone (6 Scheme 12). 

Valeton), Zingiberaceae Habit. India, China, East Indies. Constit. Yellow coloring matter (curcumin), p.p-dihydroxy -dicinnamoyImethane, p-hyd roxycinnamoyIferu loylmethane, p.a -dimethyibenzyl alcohol, 1 -methyl -4 -acetyl -1 -cyclohex -ene. turmerone. a -phellandrene, sabinene, zingiberene, cine-ol. borneol, caprylic acid, lsoln of curcumin from turmeric Janaki, Bose, J. Indian Chem. Soc. 44, 985 (1967). 

Four anti-tumor bisabolane sesquiterpenes, a-curcumene (224), ar-turmerone (225), P-atlantone (226) and xanthorrhizol (227), were isolated from the rhizomes of C. xanthorrhiza and 224 was reported to be the most active compound [170]. On further examination of the rhizomes, four additional bisabolanes, bisacurone (228), biscumol (229), bisacurol (230) and curlone (231) were obtained [171]. The absolute stereostructures of compounds 228-231 were determined by spectroscopy methods, chemical conversions and the CD exciton chirality method for allylic alcohols [171]. In more work by the same group, four related sesquiterpenes, bisacurone epoxide (232), bisacurone A (233), bisacurone B (234) and bisacurone C (235) were isolated from the same extract and their stereostructures were... 

Nitriles can be used as starting material for the bisdithioesters (62 n = 4, 5, lO), whereas the derivatives with shorter chain lengths (62 n = l-3), as well as methyl dithiocinnamate (63), are accessible from /VA -disubstituted thioamides via the corresponding imidothioate iodides. Methyl di-thioacrylate (65), the simplest unsaturated dithioester, was prepared by flash vacuum thermolysis of a precursor dithioester (64), which had been obtained from the corresponding nitrile (equation 64). It can be isolated as a red monomeric compound at 77 K but dimerizes rapidly at room temperature. The p,7-unsaturated isoprene derivative (66) and the methyl 2-arylpropanedithioates (67) were prepared from phenyl isothiocyanate and used as educts for syntheses of lavandulal and ar-curcumene. Also ethyl furane 3-carbodithioate (68), as prepared from the nitrile, has found application in syntheses of the natural products egona ketone and ar-turmerone. ... 

Monocyclic sesquiterpenic ketone (-f)-flr-turmerone (8-52) is the main component (25-50%) of turmeric essential oil (see Table 8.32). It is formed by oxidation of hydrocarbon (-l-)-flr-curcumene, which is present in turmeric rhizomes at a level of about 6%. Bicyclic sesquiterpenic ketone is (-l-)-nootkatone (8-52), which is an important odorous compound of grapefruits formed by oxidation of hydrocarbon (-l-)-valencene via alcohol (-l-)-P-nootkatol. Another oxidation product of valencene is... 

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