Contribution a l'étude des composés sesquiterpéniques—II

Volatile constituents of vetiver: a review

“…The first account of the presence of a tricyclic sesquiterpenic alcohol in VEO was given by Ruzicka, but its exact structure could not be elucidated at that time. Thirty years later, other authors probably isolated the same compound from Congolese VEO, and proposed the structure of tricyclovetivenol (Figure ), deduced after chemical degradations and IR analyses . Shortly after, a tricyclic alcohol was isolated from a South Indian VEO, and named ‘khusimol’.…”

“…A typical example is provided by zizanoic acid ( 87 ): initially it was identified as ‘khusenic acid’ in Khus oil and subsequently in Japanese VEO by Kido, who named it ‘zizanoic acid’ . Such situations produced several different synonyms that could be attributed to a single compound, as in the case of khusimol ( 77 ), which was also described as ‘tricyclovetivenol’ and ‘khusenol’ until Nigam demonstrated that all these names referred to the same unique structure . A similar example is found with ziza‐6(13)‐ene ( 62 ), tricyclovetivene, khusene and khusimene .…”

“…By analogy with ‘tricyclovetivenol’, bicyclovetivenol refers to a bicyclic constituent of VEO isolated in the early analytical studies of VEO and for which another incorrect perhydroazulenic structure was attributed (Figure ). On the basis of Marshall's work on β‐vetivone, its structure was later revised by Takahashi and described as an eremophillane alcohol for which a ( Z )‐ stereochemistry was arbitrarily attributed to the C 7 –C 11 double bond .…”

“…The CAS RN (28908-26-1) was indeed attributed to the other structure, bearing the double bond in position 9(10)-, but the actual 1(10)-position of 4 was eventually proven by König. [190] By analogy with 'tricyclovetivenol', bicyclovetivenol refers to a bicyclic constituent of VEO isolated in the early analytical studies of VEO [59,108,109] and for which another incorrect perhydroazulenic structure was attributed ( Figure 3). On the basis of Marshall's work on β-vetivone, its structure was later revised by Takahashi and described as an eremophillane alcohol Figure 2.…”

“…Evolution of the structures proposed for α-vetivone and β-vetivone [85,87,88,[95][96][97][98]100] Figure 3. Evolution of the structures proposed for isovalencenol [59,90,[108][109][110] Volatile constituents of vetiver [1,7,26,40,45,64,[75][76][77][78] GC-O, [54] GC × GC-MS, [25] GC/FTIR, [76] IR, [7] 1 H-NMR, [7,27,64] 13 C-NMR, [64] UV [7,27] Carrot-like, flowery [54] 4 202…”