Etudes sur les matières végétales volatiles XIII. Sur les α‐ et β‐vétivones

Abstract

Etudes SUP les matieres vegetales volatiles XIII1).Sur les a-et p-vetivones par Y. R. Naves e t E. Perrottet. (29. XI. 40.) A . St. Pfau et PI. A . Plattnw ont Ptabli que les essences de v@tiver renferment en proportions dlevkes un mklange de cBtones sesquiterpdniques, a-@thknoldes, bicycliques. Ces auteurs en ont isol@, par l'intermkdiaire des semicarbazones, les K -et P-re'tivones 2). 11s on$ attribut! 21, la P-vPtivone la formule suivante, d'un d6rivP d'un hexahydro-v6tivazul&ne3) 4, :En poursuivant ces travaux, nous avons recortnu que l'a-v&ivone r6pond B la mFme formule plane, et nous avons recherche la nature de l'isomkrie spatiale. Plusieurs dt!ri& de la P-vktivone ont P t B pr6par6s a nouveau, afin de les mieux d6finir et de les comparer efficacement 6, leurs congBnBres d@riv@s de l'a-dtivone. En ddcrivant plus tard les isombres thermostables de ces deux cetones, nous prhciserons la structure tlu coiistituant principal, plus ou moins raedmis4, du melange appelB (( isovktivones 1) par Yfau et Plattn tr et qui nous a paru &re un isomere trans-cyclique des K -et ,b-vPtivoiies regardees comme produits cis-cycliques. Le pr6sent mhioire renferme les considPrations d'ordre g4nPral devant Bclairer ces problPmes tl'isom6rie. Les vPtivones de la, formule ci-dessus posskclent trois atomes de carbone asymktriques : il existe donc quatre vetivones racemiques, en vertu de la mobilitt! des fornies de Xachse-M.rc4r de l'hepta~ycle~). E)lles r4pondent aux formules strueturales suivantes, pour lesquelles nous adaptons une nomenclature proposke par 8 L~' t n~)~) ; cis-ct transsont relatifs, en premier lieu, & la liaison pontale (1,5). l) XlIArne communication: Helv. 23, 912 (1940). 2, Helv. 22, 640 (1939). 4) Structure du vPtivazulPne: P/arr et Plattner, Helv. 19, 865 (1936); Synthhe du vetivazulhe: ibid. 22, 640 (1939). 5 ) N o h r , J. pr. [2] 98, 318 (1918): 103, 316 (1922); voir aussi Baker e t Itzgold, Soc.

Volatile constituents of vetiver: a review

“…Relatively low , legume and styrax Very strong , woody , citrus ( nootkatone ), key component of vetiver . Undoubtedly plays the major role in contributing the true odor of vetiver …”

“…Historically, the first constituents isolated from vetiver were obtained by the crystallization of the semi‐carbazone derivatives of components of the ketonic fraction. These pioneering works were conducted in the Givaudan company by Plattner and Pfau and shortly after by Naves and Perrottet . Two purified ketones were isolated by this process, and were named α‐ and β‐vetivones .…”

“…β‐vetivone, obtained in crystalline form, was the first to be submitted to structural analysis and was described as a bicyclo[5.3.0]octane (hydroazulene) derivative (Figure ), on the basis of dehydrogenation experiments leading to vetivazulene . As α‐vetivone displayed very similar physical and chemical properties, it was initially considered as an epimer of β‐vetivone, differing only by the configuration of carbon C 3 . The revision of these structures was made eventually almost 40 years later, after synthesis of incorrect hydroazulenic forms with spectral data that did not match those of the natural samples .…”

“…Even if their structures were incorrectly described, their odour was carefully reported: α‐vetivone ( 13 ) was described as possessing a ‘characteristic vetiver note, sweet, very pleasant, but potent and warm’. In contrast, β‐vetivone ( 49 ) was ‘relatively weak, styrax‐ and vegetable‐like’ . Surprisingly, Maurer (from Firmenich) described later that 13 and 49 were ‘relatively weak and uninteresting’, but pointed out for the first time that 64 was an important olfactory contributor, possessing a characteristic vetiver note.…”

Unravelling the Scent of Vetiver: Identification of Character‐Impact Compounds

“…The olfactory properties of 1 and 2 have long been a subject of controversy between fragrance companies. In the early studies, Naves and Perrottet (Givaudan) described 2 as weak, styrax, vegetable-like, while 1 had a characteristic potent and warm vetiver note [5]. In contrast, Maurer (Firmenich) reported that both 1 and 2 were relatively weak and uninteresting [12], while Mookherjee et al (IFF) described 2 as one of the most important contributors to the vetiver odor [13].…”