Sesquiterpene farnesanes

Drimane, farnesane, glutinopallane, protoilludane, isolactarane, and guaiane sesquiterpenes have been isolated so far in a few Lactarius species therefore, they may be considered chemotaxonomic markers. By contrast, large quantities of marasmane, lactarane and secolactarane metabolites occur in almost all Sections, as reported in Table 24. 

Recently, the farnesane sesquiterpenes 1.1-1.9 (Table 1) have been isolated for the Brst time from Lactarius porninsis, the only species of the Section Zonarii investigated so far (8). Pominsal (1.1), porninsol (1.2) and the esters 1.3-1.9 show a high thermal and photochemical lability because of the conjugated tetraene system and readily polymerize when their solutions are taken to dryness. Therefore, special mild conditions are required for their isolation and for recording the spectroscopic data. The composition of the ester mixture 1.3-1.9 was established by capillary GC and GC-MS analysis of the methyl esters obtained by transesterification (8). 

Undoubtedly one of the major highlights in the sesquiterpenoid field this year has been the very interesting results concerning the co-occurrence patterns and in vitro conversions of sesquiterpenes within the farnesane,bisabolane,curcumane, acorane, alaskane, cedrane, and zizaane groups. For instance, Kaiser and... 

Gamba-Invernizzi, A., L. Garlaschelli, A. Rossi, G. Vidari, and P. Vita-Finzi New Farnesane Sesquiterpenes from Lactarius porninsis. J. Nat. Prod., 56, 1948 (1993). 

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