Callosobruchusic acid

While the unbranched 204-207 clearly originate from the acetate pool, the structure of ( )-3,7-dimethyl-2-octene-l,8-dioic acid, callosobruchusic acid 207, a female produced copulation releasing pheromone of the azuki bean weevil, Callosobruchus chinensis [374] points to a terpenoid structure. The synthetic enantiomers [375] proved to be equally effective in releasing copulation behaviour in males. 

It is interesting to note that the C. maculatus compounds show an isoprene sub-unit which bears the unsaturation and the carboxylic moiety just like callosobruchusic acid 207. A propanoate (or methylmalonate) starter would formally complete the biogenesis of the structures. 

Recently, both enantiomeric forms of callosobruchusic acid (170), a pheromone of the azuki bean weevil, Callosobruchus chinensis L., which induces the male to extrude his genital organ and to attempt copulation, were synthesized by Mori et al.178), applying Evan s alkylation method in natural product synthesis as the key step. Thus, (S)-prolinol propionamide was converted to its enolate (164) by treatment with LDA. 

The first requisite for practical use was achieved by the synthesis of callosobruchusic acid, and the substitution of a complex hydrocarbon mixture by octadecane. Only the (E) form was active. Synthesis of the two optical forms was also achieved, but both forms showed the same activity as the natural callosobruchusic acid, thus making it impossible to assign the absolute configuration (5). The second requirement has been pursued by selecting different dummies. When an amount of erectin equivalent to that of one female was applied to a glass rod, the male attempted copulation, but did not ejaculate. However, the male did show the insertion and ejaculation behavior with a dummy of aluminum foil tube bearing erectin. 

Callosobruchus chinensisa Erectin (callosobruchusic acid + mixture of other compounds) (E)-3,7-dimethyl-2-octene-1,8-dioic acid a mixture of methyl branched, long-chain hydrocarbons... 

Females of the cowpea weevil, Callosobruchus maculatus, release a male attracting pheromone from the tip of their abdomen. The volatile signal contains five unsaturated, branched C8-acids 208-212 [376,377]. Individual compounds proved to be active while mixtures showed additive effects. Similarly, compounds 208 and 209 have been identified as the female produced sex pheromone of C. subinnotatus [378], while 209 had been described as the sex pheromone of C. analis [379]. However, GC-MS analyses of female produced volatiles of C. analis failed to detect any of the C. maculatus compounds, but did find an unidentified C8-acid with a retention time different from any of the C. maculatus acids [377]. 

Coumarin (O.T%), ferulic acid (0.1%) and -coumaric acid (5%) were shown to be toxic to the larvae of the bruchid beetle, Callosobruchus maculatus (96). 

The diacid corresponding to 114 is callosobruchic acid (115), and forms part of the copulation release pheromone of the azuki bean weevil, Callosobruchus chinensis Both chiral isomers have been synthesized by Mori et al. from methyl geranate epoxide (123). After scission of the epoxide group, the iodide 124 was made conventionally, then the chiral group was introduced using the Evans (R)- or (5)-prolinol propionamide enolate anion (125) (made with lithium diethylamide in tetrahydrofuran on the amide). Removal of the proline group... 

Cyclopropenoid fatty acids (Fig. 2.17) inhibit fatty acid desaturation in several species, including chicken, rat, pig, cow, and trout, causing a rise in the stearate to oleate ratio. This may have an effect on the composition and function of membranes as variation in lipid composition is known to alter permeability of membrane systems. Numerous types of deleterious effects from consumption of seed oils with cyclopropenoid fatty acids have been observed (Seigler, 1979). A cyclopropene fatty acid from Sterculia foetida oil was lethal to the larvae of Callosobruchus maculatus at 0.1% in artificial diets (Janzen et al., 1977). The most important edible oil with these compounds is cottonseed oil from Gos-sypium hirsutum (Malvaceae). Much of the cyclopropenoid... 

Homoarginine (L-2-amino-6-guanidinohexanoic acid) (60) (Fig. 13.13) has been isolated from a large number of Lathyrus species. This nonprotein amino acid is toxic when fed to the larval bruchid beetle Callosobruchus maculatus at the 5% level in artificial diets (Rehr et al., 1973b). 

Other compounds [e.g., miserotoxin (80)] involve 3-ni-tropropanol moieties. These compounds are poisonous to livestock (Stermitz and Yost, 1978) and to several insects and other animals (Byers et al., 1986). 3-Nitropropionic acid (78) is toxic to the bruchid Callosobruchus maculatus at... 

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