Verbenols

The western pine beetle Dendroctonus brevicomis is perhaps the most destmctive insect enemy of western pine forests. The aggregation pheromone is a mixture of the terpenoid myrcene [123-35-3J (163) from the tree and the frass pheromones exo-hsevicomki [20290-99-7] (164) and frontalin [28401-39-0] (165). The Norway spmce beede Ips tppopraphus converts the tree terpenoid myrcene into the frass pheromone ipsdienol [33628-00-3] (166) and the beedes also produce 2-methyl-3-buten-2-ol [115-18-4] and rir-verbenol [473-67-6] (167), all of which are components of the aggregation pheromone. 

It is convenient to here mention the hydrocarbon verbenene, C,gH,4, on account of its relationship with pinene. It results from the action of acetic anhydride on verbenol, thei alcohol corresponding with the ketone, verbenone. So produced it is laevo-rotatory. The dextro-rotatory and racemic varieties are also known. The sesquiterpenes have the following characters when regenerated from their respective dibromides —... 

After identification of A9-THC as the major active compound in Cannabis and its structural elucidation by Mechoulam and Gaoni in 1964 [66], a lot of work was invested in chemical synthesis of this substance. Analogous to the biosynthesis of cannabinoids, the central step in most of the A9-THC syntheses routes is the reaction of a terpene with a resorcin derivate (e.g., olivetol). Many different compounds were employed as terpenoid compounds, for example citral [67], verbenol [68], or chrysanthenol [69]. The employment of optically pure precursors is inevitable to get the desired (-)-trans-A9-THC. 

This synthetic route allows one to proceed from the alkylresorcinol dimethyl ether without using a compound of the verbenol or cyclohexanone type. 

Racemic alpha-pinene will yield racemic verbenol which will give one-half the yield of (-) verbenol. 

Oxygenated monoterpenes which are found in almost every bark beetle species attacking coniferous trees, include czs-verbenol 246, frans-verbenol 247, and myrtenol 248, representing primary products of allylic oxidation of the host terpene a-pinene 45. Further oxidation of 247 or 248 leads to the... 

The catalysts Co-CMS5 and C0-CMS6 have also been tested for the air oxidation of a-pinene. In both the cases air oxidation commences quickly with the formation of a-pinene oxide, verbenol and verbenone as the main products along with other rearranged products as observed in the reactions described above. A conversion of 50.6% and 48.0% are observed for Co-CMSS and C0-CMS6 respectively after 24h (Table 6). 

The MIL-supported POM eatalysts were eharaeterized by elemental analysis, XRD, N2 adsorption, and FT-IR-speetroseopy, whieh indieated the preservation of both MIL and POM structures after immobilization. The eomposite M-POM/MIL-101 materials demonstrated fairly good catalytie performanee in a-pinene allylie oxidation (81-84 % verbenol/verbenone seleetivity at 15-25 % substrate eonversion) and earyophyllene epoxidation (100 % selectivity at 88 % conversion) with green oxidants - H2O2 (Ti-POM) and O2 (Co-POM) [126]. 

The catalytic properties Co-POM/Si02 were assessed in oxidation of IBA to isobutyric acid [96] and a-pinene to verbenol/verbenone [97] with molecular oxygen as well as in a-pinene/lBA co-oxidation to produce the corresponding epoxide and carboxylic acid [97]. In turn, the catalytic performance of Ti-POM/Si02 was examined in a-pinene oxidation to... 

Biotransformation of (+)- and -)-cis/trans- etheno s to (-f)-verbenone has been achieved by a cell-free system of Cannabis sativa Callus.The (—)- and (+)-verbenone (via verbenol) were the starting materials for the first synthesis of the (—)- and (+)- enantiomers of A -tetrahydrocannabinol. 

Oxidative cleavage of monocyclic and bicyclic allylic alcohols to keto acids and di-acids respectively is effected by RuClj/aq. Na(IO )/CCl -CH3CN thus trans-verbenol gave (+)-c/x-pinononic acid and (+)-frani-pinocarveol yielded (-)-cis-pinic acid (Table 3.6) [237]. The double bond in diphenylcholene was cleaved by RuOj/aq. Na(IO )/CCl to aldehyde and acid (Table 3.4) and the adjoining phenyl rings destroyed [238]. 

Attempts to investigate boll weevil (Anthonomus grandis) pheromone biosynthesis have identified isomerization, dehydration, and oxidation of the pheromone alcohols, and anticipated allylic oxidation of myrcene and limonene, but no evidence for the cyclization of acyclic precursors. The aggregation pheromones of bark beetles have been reviewed. Ips calligraphus responds to ipsdienol only in the presence of the c/5-verbenol (32) large additional concentrations of the enantiomer (l/ ,4i ,5/ )-(32) reduce beetle response. 5-(-)-Ipsenol, the pheromone of Ips grandicollis, increases the response of /. avulsus to its own pheromone ipsdienol. ... 

Mori et al. have now synthesized the cfs-verbenols [(32) and its enantiomer] in optically pure state using essentially the same route as used for frans-verbenol (Vol. 7, p. 41) in connection with optical purity and stereochemical comparisons based upon optical rotations, it is of interest to note that optically pure (32) has [a]o = —9.8° in chloroform and [a]o = +11.4° in methanol and +6.2° in acetone, emphasizing the value of using chiral designations." ... 

---