Pheromones cockroach

The EAG technique as a bioassay tool for active fractions has been used in the identification of sex pheromones of many insect species in several orders and remains as a key factor in the identification of pheromones. In the recent identification of the brownbanded cockroach pheromone supellapyrone (7) (Figure 2), the EAG technique was used throughout the entire process of isolating and purifying active material from 12,000... 

Our research on cockroach pheromones has been supported by grants from the National Science Foundation (IBN-9817075), the United States Department of Agriculture Competitive Grants Program (2002-02633), and the Blanton J. Whitmire Endowment and the W. M. Keck Center for Behavioral Biology at North Carolina State University. 

Bykhovskaia, M. B. and Zhorov, B. S. (1996). Atomic model of the recognition site of the American cockroach pheromone receptor. Journal of Chemical Ecology 22 869-883. 

Methyl-branched ketones (German cockroach pheromone)... 

For the preparation of the second component 421 of the cockroach pheromone Burgsthaler et al. 228) also used a Wittig reaction. Lithium acetylide is alkylated with the two halides 414 and 416 and the resulting alkynyl bromide 417 converted into the phosphonium salt. Olefination of the corresponding ylide with 9-bromo-2-nonanone 418 gives a (Z)/( )-mixture of olefin 419 which is converted into the pheromone 3,ll-dimethyl-29-hydroxynonacosan-2-one 421 by aeetoaeetate synthesis, hydrogenation, hydrolysis, and decarboxylation 228) (Scheme 73). 

The synthesis of a cockroach pheromone required pericyclic reactions... 

In 1986 Hauptmann in Germany attempted the reisolation of the American cockroach pheromone, and found a potent pheromonally active compound with spectral properties different from those reported for periplanone-A of Persoons. Hauptmann clarified the structure of his compound as 79, and named it periplanone-A. 

I explained this category in the case of the German cockroach pheromone (104), and also discussed the spined citrus bug pheromone [(3/ ,4S)-74], whose opposite enantiomer was as active as the pheromone itself. Females of the maritime pine scale Matsucoccusfeytaudi) use (3.S ,7R)-118 as the sex pheromone. Its OR,1R )-isomcr also showed bioactivity similar to the natural pheromone, while M. feytaudi males responded very weakly to the two other stereoisomers. It therefore seems that only the stereochemistry at C-7 of 118 is important for the expression of pheromone activity.139... 

The protection of an a, p-unsaturated ketone by a conjugate addition strategy is the subject of our last example but it does not involve the use of an 0,0-acetal. During a synthesis of the cockroach pheromone Periplanone B. Still needed to perform a copper(I)-mediated Sn2 reaction on the allylic acetate 37.1 [Scheme 2.37], In order to prevent competing addition to the a, p-unsaturated ketone, it was protected temporarily by conjugate addition of trimethylstannyl-lithium and trapping of the intermediate enolate with chlorotrimethylsilane. The desired Sn2 reaction was then performed on the adduct 37.2 and the a.p-un-saturated ketone recovered by oxidation of the C-Sn bond to a C-OH using m-chloroperbenzoic acid. Concomitant destruction of the labile enol ether and -elimination of water returned the a, p-unsaturated ketone 373. 

Germacrene D (67) provides an active mimic of the American cockroach pheromone, periplanone B (68) (Bowers, 1985). 

Asymmetric acetylation of ( )-30 with vinyl acetate and lipase AK left (2R,4S,6S)-30 intact, while its enantiomer was acetylated to give (2S,4R,6R)-31. The hydroxy ester (2R,4S,6S)-30 was converted to the cockroach pheromone, supellapyrone (Figure 24.16) [19]. 

The syntheses of the cockroach pheromone periplanone B (136) by Still [92] and Schreiber [93] constitute classics in natural products syntheses, as... 

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