Verbenol, + -trans

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]. 

Weber e.t al. utilized dinuclear (i-oxo iron(III) phthalocyanines 18 as catalysts in the aerobic oxidation of a-pinene lg, resulting in the formation of trans-verbenol 2g, verbenone 3g and a-pinene oxide 4g in almost equimolar amounts. Additionally, 3-pinen-2-ol 19 was obtained (Scheme 3.28) [119]. 

Miller et at, 1997), terpinen-4-ol (Kohnle et at, 1985), cis- and trans-verbenol (Silverstein et at, 1966a Renwick, 1967 Pitman et at, 1968 Rudinsky et at, 1972 Hughes, 1973b Francke and Heeman, 1976 Mori,... 

Pitman G. B., Vite J. P, Kinzer G. W. and Fentiman A. F. (1968) Bark beetle attractants trans-verbenol isolated from Dendroctonus. Nature 218, 168-169. 

Renwick J. A. A., Hughes P. R. and Krull I. S. (1976a) Selective production of cis- and trans-verbenol from (-)- and (+)-a-pinene by a bark beetle. Science 191, 199-201. 

Both a- and P-pinenes are popular starting materials for the synthesis of other monoterpene chiral synthons such as carvone, terpineol, and camphor (vide infra). Reactions leading to other monoterpenes are briefly summarized in Figure 5.1. Treatment of a-pinene with lead tetraacetate followed by rearrangement gives trans-verbenyl acetate (7), which is hydrolyzed to yield trans-verbenol (8) 8 Subsequent oxidation of 8 gives verbenone (9), which can be reduced to give cw-verbenol... 

The adsorptive separation of pinenes on Zeolites is reported.303 The C-6 and C-7 13C n.m.r. chemical shifts in bicyclo[3,l,l]heptanes support other known conformational evidence and confirm that cls-pinane and ds-myrtanol (209 X = OH) have a bridged-boat conformation, that trans-myrtanol has a bridged-chair conformation, and that trans-2-pinanol and myrtenol (210 X = OH) have Y-shaped conformations verbenone (211 R R2 = O), and trans-verbenol (211 R1 = H, R2 = OH) give anomalous results which may be due to a conjugation effect the bridged-chair... 

The faecal pellets of the bark beetle Ips paraconfusus which had fed on the phloem of Pinus ponderosa contained large quantities of the aggregation pheromones cis-verbenol (24), ipsenol (25), and ipsdienol (26). The pheromones originate in the hindgut, but, although there is a precursor-product correlation between a-pinene or myrcene from the phloem and the pheromone terpenoids, the biosynthetic site is unclear. The demonstration68 of the conversion of a-pinene into cis- and trans-verbenol (27) by Bacillus cereus found in the gut of I. paraconfusus has led to the... 

The aggregation pheromone of Dendroctonus brevlcomls Leconte consists of a synergistic mixture of exo-brevicomin (IV) produced by females, myrcene (V) from the host tree, and frontalin (VI) produced by males which respond to compounds IV and V. The mixture of all three compounds then attracts males and females (10). Subsequently, verbenone (VII) and trans-verbenol (VIII) are produced and deter further attack (11.). Additionally verbenone deters the response of I. paraconfusus which utilizes the same host tree species in the same area (16,17). Thus the two species may be found colonizing different parts of the same tree. Again, as in the Ips pheromones, chirality plays a role. The naturally occurring enantiomers of exo-brevicomin and frontalin in combination with myrcene elicit a greater response from both male and female D. brevlcomls than do the other enantiomers. 

It is suggested that micro-organisms introduced by Dendroctonus frontalis may be responsible for the conversion of the aggregation pheromone trans-verbenol into verbenone which inhibits further attack by the pine bark beetle (cf. Vol. 6, pp. 13, 179, 180). ... 

The conformations of the verbanols have been discussed in relation to their n.m.r. spectra. The photochemical conversion of verbenone (347) into chry-santhenone (359) is discussed again, and it has been shown that the same reaction occurs with y-radiation. In the latter case the conversion is small, verbenone being surprisingly stable towards y-radiation. In these conditions, trans-verbenol is also stable, but cis-verbenol is converted into a mixture of the trans-isomer and verbenone. The known apoverbenone (360) has been made by a much improved route.The first stage, N-bromosuccinimide bromination of nopinone (361) leads initially to the a-bromoketone (362) (this is the kinetic... 

Eriksson, K., Levin, J.O., Identification of cis- and trans-verbenol in human urine after occupational exposure to terpenes. Int. Arch. Occup. Environ. Health, 62,379-383,1990. 

Fig. 12.1 Aggregation pheromones of (a) Ips paraconfusus, three male-produced synergistic components - (+ )2-methyl-6-methylene-2,7-octadien-4-ol (ipsdienol) (-)2-methyl-6-methylene-7-octen-4-ol (ipsenol) and cw-verbenol. (b) Dendroctonus brevicomisj three attractive components, cxo-7-ethyl-5-methyl-6,8-dioxabicyclo-[3.2.1] octane (cxo-brevicomin) from the female l,5-dimethyl-6,8-dioxabicyclo-[3.2.1] octane (frontalin) from the male and myrcene released from the host tree. Verbenone and trans-verbenol, released after a male locates the female, interrupts response to the attractant blend.

Knowledge of the biosynthesis of bark beetle pheromones has been largely conjectural, based on simple metabolic pathways from host terpenes. However, the biosynthetic routes of the pheromone components of 7. paracon-fusus are now known (Fig. 12.3). Both sexes produced m-verbenol when exposed to (-)ff-pinene (Renwick et al., 1976), and tran -verbenol from (+)a-pinene. When exposed to the vapour of myrcene, ipsdienol and ipsenol appeared in the hindguts of male beetles, but not in females (Hughes, 1974 Hughes and Renwick, 1977 Byers et al., 1979), whereas no pheromone was detected in the guts of beetles not exposed to myrcene. Deuterium-labelling techniques have now confirmed that myrcene is converted in male I. para-confusus to ipsdienol and ipsenol (Hendry et al., 1980). Thus, all three known pheromone components are obtained by simple oxidation of host plant chemicals. 

In D. brevicomis, verbenone and trans-verbenol are produced by both sexes and inhibit response to the aggregation pheromone (Wood, 1972 Bedard et al., 1980a). The precise nature and timing of the stimuli triggering release of each... 

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