C/s-Verbenol

Figure 6.11 Biosyntheses of isoprenoid pheromone components by bark and ambrosia beetles from host conifer monoterpenes. (A) Conversion by the male California fivespined ips, Ips paraconfusus Lanier (Coleoptera Scolytidae), of myrcene from the xylem and phloem oleoresin of ponderosa pine, Pinus ponderosa Laws., to (4S)-(+)-ipsdienol and (4S)-(-)-ipsenol, components of the aggregation pheromone (Hendry et al., 1980). (B) Conversion by male and female I. paraconfusus of (1 S,5S)-(-)-a-pinene (2,6,6-trimethyl-bicyclo[3.1,1]hept-2-ene) from the xylem and phloem oleoresin of P. ponderosa to (1 S,2S,5S)-(+)-c/s-verbenol (c/s-4,6,6-trimethyl-bicyclo[3.1,1]hept-3-en-2-ol), an aggregation pheromone synergist and of (1 R,5R)-(+)-a-pinene to (1 fl,2S,5fl)-(+)-frans-verbenol (frans-4,6,6-trimethyl-bicyclo[3.1,1]hept-3-en-2-ol), a compound of unknown behavioral activity for /. paraconfusus. Male and female western pine beetle, Dendroctonus brevicomis LeConte (Coleoptera Scolytidae), convert (1 S,5S)-(-)-a-pinene to (1S,2ft,5S)-(-)-frans-verbenol, an aggregation pheromone interruptant and (1R,5R)-(+)-a-pinene to (1 R,2S,5R)-(+)-frans-verbenol, a compound of...

The Pheromone Dispensers and their use. Two kinds of dispensers were used, both marketed by Borregaard Ind. Ltd., Sarpsborg, Norway. 1. A plastic bag formulation produced by Celamerck, In-gelheim, West-Germany. 2. A laminated plastic-tape formulation produced by Herculite Products Inc., New York, N.Y., U.S.A. One dispenser contained 1500 mg methylbutenol, 70 mg (S)-c- s-verbenol and 10 mg (1979) or 15 mg (1980) ipsdienol. 

The reference standards of different monoterpenes, sesquiterpenes, and alkanes were obtained from Aldrich Chemical Co., Inc. (Milwaukee, WI, USA), Fluka Chemical Corporation (New York, NY, USA), Roth Co. Chemische Fabrik (Karlsruhe, Germany), Sigma Chemical Co. (St. Louis, MO, USA) and Varian Associated (Houston, TX, USA). These reference standards include tricyclene, a-pinene, sabinene, a-phellandrene, 1-decene, limonene, fenchone, a-terpineol, a-terpinolene, c/s-verbenol, cis- and trans-carveol, cA-dihydrocarveol, a-longipinene, a-cedrene, (-)-isolongifolol, a-humulene, valencene, cuparene, myristyl alcohol, citronellyl acetate, neryl acetate, geranyl acetate, camphene, alloaromadendrene, -eicosane, and n-heneicosane. Solutions were prepared in methanol at concentrations of 10 mg/mL. For GC/MS analysis each standard solution was diluted by mixing 0.1 mL of the standard solution with 0.9 mL of methanol. 

It is the biosynthesis of the oxygenated monoterpenes that influence bark beetle behavior that provides us with an interesting and largely unresolved problem. The main compounds identified in this category are tra 5-verbenol (232) 373), c/s-verbenol (234), 2-methyl-6-methylene-7-octen-4-ol (ipsenol) (240), and 2-methyl-6-methylene-2,7-octadien-4-ol (ipsdienol) (266) (see Chart 1) 136). The reaction for the biosynthesis of all these compounds seems to be the allylic hydroxylation of a-pinene and mycrene, both of which occur in abundant amounts in host pine trees. 

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