Famesane

Individual saturated hydrocarbons including n-alkanes (w-Cg through M-C40) and selected isoprenoids pristane (2,6,10,14-tetramethyl-pentadecane) and phytane (2,6,10,14-tetra-methyl-hexadecane). In some cases, another three highly abundant isoprenoid compounds famesane (2,6,10-trimethyl-Ci2), 2,6,I0-trimethyI-Ci3, and norpristane (2,6,I0-trimethyI-Ci5) are also included ... 

CijHioOj, Mr 248.32, mp. 158 °C, (alp +109° (CHClj). A sesquiterpene of the drimane group, isolated from Drimys winteri (Winteraceae), a South American tree or bush now grown as an ornamental tree in Ireland and the Mediterranean region. The biosynthesis of the drimanes proceeds by direct cyclization of famesane derivatives. 

The chains of some fliranoid famesane derivatives are terminated by furan rings. Dendrolasin from sweet potatoes, also isolated from some marine snails, for example, is an alarm and defense pheromone of the ant Dendrolasius fulginosus. Ses-quirosefuran and longifolin occur in the leaves of Actinodaphne longifolia. 

Formally, C-1 and C-6 of famesane close a cyclohexane ring in the bisabolanes, which represent a more prominent class of monocyclic sesquiterpenes. Additional cyclizations increase the diversity. More than 100 bisabolane derivatives of plant origin are known to date... 

Ring closure of C-1 and C-11 of famesane, not only formally but also in biogenesis via famesyldiphosphate, produces the sesquiterpene skeleton of more than 30 naturally oeeurring humulanes Regioisomeric a- and p-humulene occur in the leaves... 

Carbon atoms C-1 and C-10 in addition to C-2 and C-7 of famesane link up to close the eudesmane bicyclic skeleton of sesquiterpenes with trawj-decalin as core structure with corresponding numbering of the ring positions. To date, about 500 eudesmanes, formerly referred to as selinanes, have been documented in the litera-... 

Bond formation between C-2 and C-7 as well as C-6 and C-11 of famesane formally leads to the drimane basic skeleton of sesquiterpenes The accepted numbering system is derived from decalin and not from famesane. The parent hydrocarbon 5a,8a,9p,10p-drimane with irans-decalin as core stracture occurs in paraffin oil. 

Bonds between C-1 and C-6 as well as C-1 and C-11 formally convert famesane into the bicyclic skeleton of himachalane with the numbering system adopted from that of famesane. Several himachalanes such as a-himachalene and himachalol are constituents of the oil of cedar wood from Cedrus deodara (Pinaceae). 

Longipinanes are differentiated from longifolanes whieh formally and biogeneti-cally also emerge from famesane by eleaving the C-3-C-4 bond and elosing the... 

Bonds from C-1 to C-7 and from C-1 to C-10 in famesane formally build up the sesquiterpene skeleton of isodaucanes which are converted to daucanes by migration of one methyl group (C-14) from C-7 to C-8. 

Culture of the phytopathogenic fungus Stereum purpureum (Basidomycetae), a parasite of some trees, produces unsaturated and hydroxylated sesquiterpenes wifli the tricyclic skeleton of sterpurane, formally arising from isolactarane by opening the C-5-C-6- and closing the C-4-C-5 bond, or directly from famesane by Unking the bonds C-l-C-11, C-2-C-9 and C-4-C-7. 

Connecting the bonds C-l-C-6 and C-6-C-10 in famesane formally produces the spiro[4,5]decane basic skeleton of acorane. The name of this class of sesquiterpenes stems from the Acorus species. (-)-4-Acoren-3-one, for example, has been isolated from Acorus calamus (Calamus, Araceae) and from the carrot Daucus carota (Umbelliferae). The oil of calamus (oil of sweet flag) from the rhizome of Acorus calamus with its warm and spicy odor and pleasant bitter taste is predominantly used in perfumery and as a minor (possibly carcinogenic) ingredient of vermouth, some flavored wines and liqueurs. (+)-3,7(ll)-Acoradiene is a constituent of juniper Juniperus rigida its enantiomer occurs in Chamaecyparis nootkatensis (Cupressaceae). 

A spiro[5,5]undecane skeleton characterizes the chamigranes which formaUy originate from linking the bonds C-l-C-6 and C-6-C-11 of famesane. More than 50 naturally occurring representatives with halogens as substituents are predominantly... 

Bonds between C-2 and C-11, C-6 and C-10 as well as C-6 and C-15 of famesane formally link up the tricyclic sesquiterpene skeleton prezizaane, which converts into zizaane by methyl shift. 

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