Muurolene sesquiterpenes

Sampling time 60 min extraction temperature 80°C. Monoterpenes a-pinene, p-myrcene, a-phellandreneand limonene sesquiterpenes a-cubebene, a-copaene, p-elemene, p-caryophyllene, a-humulene, y-muurolene, p-eudesmene and caryophyllene oxide diterpenes cembrene A and isoincensole acetate. 

Fig. 5-3. Examples of mono- and sesquiterpenes and their derivatives in softwood. 1, a-Pinene 2, /3-pinene 3, 3-carene 4, camphene 5, borneol (R = H), bornyl acetate (R = COCH3) 6, limonene 7, a-terpineol 8, dipentene 9, a-muurolene 10, 8-cadinene 11, a-cadinol 12, a-cedrene 13, longifolene 14, juniperol.

Previous studies (Z) showed evidence for the presence of at least 20 sesquKerpene hydrocarbons in pineapple. These researchers identified 7 sesquiterpenes (1 tentative). We confirmed the presence of 3 of the sesquiterpenes and identified p-copaene, y-muurolene, a- and p-selinene in addition. Mass spectral data indicated the presence of other sesquiterpene hydrocarbons and oxygenated sesquiterpenes which we have been unable to characterize at present. 

The Philippine species of Heteroxenia yielded the sesquiterpenes a-muurolene and the new derivative 6-hydroxy muurolene (Edrada, Wray, van Ofwegen, and Proksch, unpublished data). Both sesquiterpenes were... 

In the biosynthesis of tutin (57) the involvement of copaborneol (56) has been demonstrated. As expected, only one tritium atom was incorporated from [2- C,3R,4R- H]mevalonate. Unfortunately, it is still not clear whether the biosynthesis involves a cadinene system or a germacrene system. The cadinene sesquiterpene, y-muurolene (58), and caryophyllene (59) are formed in Mentha piperitaf The labelling of the latter terpenoid (% from [2- C]mevalonate... 

In addition to common six-membered rings such as in the cadinenes, one classic bicyclic sesquiterpene is caryophyllene, which has a nine-membered ring and cyclobutane ring. Additional unsaturation provides aromatic bicyclic sesquiterpenoids such as vetivazulene and guaiazulene. Examples are caryophyllene, y-muurolene, petasin, Ipomeamarone, carotol, helminthosporal, avocettin, alkaloids of Nuphar, and mycophenolic acid. 

Westfelt L 1966 a,y, and e-Muurolene, major sesquiterpenes of the wood of Pinus sihestris L. and of Swedish sulphate turpentine. Acta Chem Scand 20 2852-2864... 

Volatile components (more than 50), which include -alkanes, sesquiterpenes, and oxygenated compounds (undecane to hexade-cane, elemenes, muurolenes, y-nonalactone, 5-methyl-8-caprolactone, etc.) and others... 

The number of sesquiterpenes is high (over 150 compounds). There are compounds with aliphatic (farnesenes), monocyclic (humulenes, bisabolenes, elem-enes), bicyclic (cadinenes, muurolenes, selinenes, caryophyllenes, germacrenes), tricyclic (copaenes, ylangenes, longifolenes.longicyclenes), and tetracyclic (sati-vene) structures. 

The simplest biogenesis of the tricyclic cedrane sesquiterpenes (Scheme 20) involves initial cyclization of the P-bisabolyl cation (211) to the spiro[4.5]decane nucleus of the acoranes followed by a second cyclization upon the remaining double bond in the cyclohexene ring (108, 285). The P-bisabolyl cation may arise less directly from (—)-y-curcumene via additional deprotonation-protonation step, a distinction which is unnecessary for the present purposes (110). An alternative biogenesis of the requisite acorenyl cation intermediate has also been proposed in which the cationic precursor to the muurolenes undergoes 1,2-hydride shift, ring contraction and finally 1,4-hydride shift (110). 

Westfelt, L. a,y, and e-Muurolene, Major Sesquiterpenes of the Wood of Firms silvestris L. and of Swedish Sulphate Turpentine. Acta Chem. Scand. 20, 2852 (1966). 

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