Humulane

As indicated in Figure 3, the cadlnanes (170 - 187) are formed from the humulane (205) system, which also is the progenitor of the caryophyllanes (206 - 208). Of these last three compounds, caryophyllene (206) itself is of particular Importance, since it can account for 20 - 25% of the essential oil of some samples (lA). Other major constituents in the same sample were copaene (173, another cadinane) and a-humulene (205), each near 15%. It is therefore apparent that the pathway involving initial conversion of Z,E-farnesyl pyrophosphate to the humulane system is dominant in Gossypiwn terpenoid biogenesis. 

Taxus hrevifolia Pestalotiopsis microcarpa pestalotipsins A and B 2a-OH-dimeninol 5-OH-10-(OH-methyl)-3,7,7-trimethyl-2,9-cycloundecadiene-l,6-dione (humulane derivative) 203... 

From ten-membered rings Borontrifluoride catalyzed conversion of germa-crane (ten-membered) to humulane (eleven-membered) in 75% yield [15]. 

Caryophyllane, Humulane, Africane, Illudalane, Protoilludane, Hirsutane, Vellerane, Pentalane, Senoxydane... 

Humulane, Caryophyllane, Protoilludane, Illudane, Marasmane, Hirsutane... 

Naya and Kotake, in an examination of Japanese hop oil, have isolated three humulane-type compounds, viz., humuladienone (161, R = Me), humulenone II (161,R = =CH2), and humulol (162), in addition to the tricyclic diol (163, R = OH), m.p. 207 °C. This diol has already been prepared in two different ways (a) Sutherland et treated humulene (164) with AT-bromosuccini-mide in aqueous acetone and converted the resultant bromohydrin (163, R = Br) to the diol (163, R = OH), m.p. 205—206 °C, by hydrolysis, (b) McKervey and Wright obtained the same diol, m.p. 201—203 °C, by acid-catalysed (20% sulphuric acid) rearrangement of humulene 1,2-epoxide (165), a known natural product. On the basis of these findings and the fact that both caryophyllene (166) and humulene can be derived from the above bromohydrin by two in vitro steps, McKervey and Wright postulated that humulene 1,2-epoxide may be involved in the biosynthesis of the tricyclic diol and caryophyllene. This postulate does not, however, readily accommodate the observed rotations of the relevant... 

C,5H24, Mr 204.36, colorless oil, bp. 123°C(1.33 kPa). Monocyclic sesquiterpene from the essential oils of many plants such as, e.g., cloves, hops, and various Didymocarpus species. a-H. is often accompanied by the isomeric /5-humulene. The completely hydrogenated, monocyclic derivative of H. is humulane. H. is the biosynthetic precursor of various sesquiterpenoids, see hirsutanes, protoilludanes, etc. formed by basidi-omycetes. 

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... 

Approximately 30 naturally abundant caryophyllanes are derived from humulanes in which C-2 and C-10 close a cyclobutane ring. 

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