Pheromones scales

Several female sex pheromones of pine bast scales were identified and synthesized. Scheme 29 summarizes Mori s synthesis of the pheromone [( )-18] of the Israeli pine bast scale (Matsucoccus josephi) [51]. Enzymatically prepared... 

Scheme 54 summarizes Font s synthesis of (+)-grandisol (36), the male pheromone of the cotton boll weevil (Anthonomus grandis) [80]. The key-step is the double [2+2] photocycloaddition of ethylene to bis(a,(3-butenohde) A to give B, which yielded C after glycol cleavage. The recently identified pheromone of the oleander scale (Aspidiotus nerii) possesses a structure similar to that of grandisol (Scheme 54), and its synthesis was reported by Ducrot [81 ] and also by Guerrero [82,83]. 

Third, some of the pheromone components are simple and cheap compounds such as straight-chain esters and aldehydes, that are readily available in bulk. Others fall into a middle ground, whereby multigram-scale synthesis to produce sufficient material for use as trap lures should be possible. However, the pheromone structures of a number of species appear to be of sufficient complexity that it is unlikely that they could be made in sufficient quantity and at affordable cost for widespread use in pheromone-based control programs. 

Weevils do not seem to be very sensitive to the presence of non-natural stereoisomers of their pheromones, since racemic mixtures proved to be active in the field. This greatly facilitates their use in large-scale integrated pest management. Some species also contain ketones, corresponding to the pheromone alcohols however, they do not show behavioural activity. 

California red scale pheromone Scheme 9 Vitamin Bi2-mediated Michael addition. 

Other examples include the synthesis of California Red Scale Pheromone [80], prostaglandin PGF2a [81], House Mouse Pheromone [63], and Jasmon-ates [82]. 

On a larger taxonomic scale, the opposite pheromone-to-hormone hypothesis (Haldane, 1955) suggested that the interindividual pheromones of unicellular organisms such as protozoans enabled metazoan development and led to internal chemical communication in and between tissues by hormones in multicellular organisms. 

The blind snake Leptotyphlops dulcis is a specialized burrower that feeds on termites and ant brood. It follows the ant pheromone trails to find its prey (Section 12.1). when attacked by ants, this snake tilts its scales individually so that the skin appears silvery. While it writhes, it covers itself with feces and a clear viscous fluid, discharged from the anus. It may also assume a stationary coiled position. when it resumes searching and feeding, it is no longer attacked by ants. The effect lasts from 3 to 30 minutes (Gehlbach etal., 1968). Here a predatory species protects itself from the defensive actions of its prey. 

Roelofs W Gieselmann M, Cardd A, Tashiro H, Moreno DS, Henrick CA, Identihcation of the California red scale sex pheromone, / Chem Ecol 4 211— 224, 1978. 

The synthesis of pheromones remains an important cornerstone of pheromone research and development. The initial synthesis of an insect pheromone serves not only to confirm the structural identification, but also provides authentic material for either laboratory or field bioassay. Oftentimes, larger quantities of the pheromones are desired for the development of monitoring and pest control methods. The scale up of the synthesis of complex pheromone compounds is often a major bottleneck in the practical application of pheromones. Also, the unusual structure of some pheromone compounds beckons synthetic chemists to apply new methodology in order to show off their methods. 

A new synthetic route has been described to prepare matsuone, the pheromone of the pine scale Matsucoccus matsumurae and a few other pine scale species. Structure activity is discussed. ... 

Mafra-Neto, A. and R. T. Cardd. Fine-scale structure of pheromone plumes modulates upwind orientation of flying moths. Nature 369, 142-144 (1994). 

Murlis, J. and C. D. Jones. Fine-scale structure of odour plumes in relation to insect orientation to distant pheromone and other attractant sources. Physiol. Entomol. 6, 71-86 (1981). 

Three approaches in Ihe use of pheromones have appeared in the literature i I I use of traps haiteil with sexual atiriieiant material as a means lor monitoring the infestation of areas with select insects 12) similar use of traps, except on a massive scale, to attrael males (female sex pheromone used as bait) and to) "male confusion" technique, in which female sex pheromone is permeated in ihe air. frustrating the attempts of males to locale females. 

The homochiral f -branched carboxylic acids (13 or enf-13 Table 1) have been used for the synthesis of a variety of natural products21 such as California red scale pheromone,14 a-skytanthine,22 the southern com rootworm pheromone,15 and norpectinatone.16 Pure (5)-3-trichloromethylbutyric acid (a structural subunit of some sponge metabolites) was prepared via conjugate addition of ClaCMgCl to the chiral cro-tonate (16) followed by hydrolysis (Scheme S).23... 

In contrast, the corresponding reactions of RCu/BFa reagents (R = phenyl or alkenyl) with allylic acetals obviously proceed in an anti 5n2 fashion, as shown in (67b). The unsaturated acetals (68), prepared from (R )-butane-1,2-diol, are opened by the PBu3-stabilized reagents to give, after hydrolysis, the (3-substituted aldehydes (69) with high ee (Scheme 27).68,69 The method has been applied to the preparation of a key intermediate (85% ee) for the synthesis of the California red scale pheromone.69... 

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