2-Tridecanone

Differences in alkaloid composition between samples of Z dipetalum from different islands have also been reported (Arslanian et al., 1990). These workers found that a tree from Oahu (anethole/estragole chemotype) lacked thalicitrine [546] (see Fig. 6.5), whereas a tree from Kauai and one from Hawaii (both 2-undecanone/2-tridecanone chemotype) possessed the compound. 

With the long chain a-diazo ketone. 6-diazo-7-tridecanone, 1,5-insertion could proceed with placement of the carbonyl outside the ring, or included in the ring. In fact, only the product 7, from the first of these two cyclization modes, is observed67. The alternative cyclopentane 9 is not formed. As with the a-diazo ester, the relative proportion of 1,2- and 1,5-products depends on the rhodium carboxylate employed. Throughout these studies, it has been observed that the olefin 8, obtained from 1,2-elimination, is cleanly Z-configured67 68. 

The structure of this allomonal factor was established as 2-tridecanone using conventional spectral data. Having Identified the compound apparently responsible for the observed toxicity, it then became necessary to quantitate the natural levels of 2-trlde-... 

Isolation of the feeding factor for M. sexta was a far more difficult task. Whereas 2-tridecanone is a simple, stable molecule soluble in organic solvents, the feeding factor is water soluble, occurs at trace levels in plant tissue, and is easily hydrolyzed under mild alkaline or acidic conditions with subsequent loss of biological activity. The isolation of such a compound was a formidable obstacle requiring a departure from the more classical approach of hydrolysis or chemical derivatization followed by isolation of the lipophilic product. The necessity that pure substance be isolated with retention of biological activity required some basic research in modem separation techniques to develop a suitably mild isolation strategy. 

The wild tomato, Lycopersicon hirsutum f, glabratum is covered with trichomes which contain 2-tridecanone. The level of this compound is much lower in the domesticated tomato, U esculentum. This exudate proved to be toxic to Manduca sexta (tobacco hornworm) and to Heliothis zea (121). The density of glandular trichomes, which secrete 2-tridecanone, was influenced... 

Reaction Cavities of Alkanones in Neat Solid Phases. The early report that irradiation of crystalline 7-tridecanone at 10°C does not result in discernible photoreaction [267] has been corroborated subsequently with other solid symmetrical n-alkanones [268]. However, careful scrutiny of the irradiated ketone reveals traces of Norrish II products in ratios which are very close to those found from photoreactions in solution. On this basis, it was concluded that the source of the photoproducts is reactions occurring at crystal defect sites. 

These expectations have been borne out by experiment [293], For instance, 2-tridecanone gives rise to E/C ratios in Na-X (1.0) and Na-Y (0.9) zeolites which are very similar to those found from valerophenone in the same media. However, whereas only fragmentation products were detected from valerophenone irradiated in ZSM-5 and ZSM-11, the E/C ratios in these zeolites with narrower channels were 4.3-4.5 from 2-tridecanone. Clearly, the channel cross sections of these zeolites (>28A2) can accommodate the c-BR conformations necessary to form cyclobutanols. 

Heptadecane 2-Tridecanone Undecanoic acid 5-Decyldihydro-2(3H)-furanone... 

Tetradecene 5-Tridecanone 6-0xoheptanoic acid Octanoic acid ethylester... 

Reagents. The solvents (n-pentane, diethyl ether) were reagent grade and glass distilled. n-Aldehydes (C6-C14) were obtained from Alltech Associates (Deerfield, IL). 2-Heptanone, 2-nonanone and 2-undecanone were obtained from Aldrich (Milwaukee, Wl) 2-tridecanone was obtained from Caro (Tokyo, Japan). Unless otherwise stated, all other chemicals were of reagent grade. Zingerone was obtained from ICN Biochemical (Plainview, NY). 

Like secondary alcohols, ketones are not common constituents of the cuticular lipids of insects (Lockey, 1988). The cuticular lipid of the female housefly, M. domestica, contains 6% of an unsaturated ketone, (Z)-14-tricosen-10-one (Uebel et al., 1978) and lesser amounts of tricosan-10-one and heptacosen-12-one (Mpuru et al 2001). The cuticular lipids of several species of Drosophila contain C13-C17 saturated and unsaturated ketones, including 2-tridecanone and 2-pentadecanone in Drosophila hydei (Moats et al., 1987), 10-heptadecen-2-one in D. mulleri (Bartelt et al., 1989), and 2-pentadecanone in D. busckii (Schaner et al., 1989). Odd-chain ketones (2-nonadecanone, 2-heneicosanone and 2-tricosanone) comprise 1% and 3% of adult male and female cuticular lipids, respectively, of the pecan weevil, Curculio caryae (Espelie and Payne, 1991). The cuticular lipids of mature screwworm females, C. hominivorax, contained small quantities of two C31 ketones the symmetrical ketone, 16-hentriacontanone and the methyl-branched ketone, 21-methyl-7-hentriacontanone (Pomonis etal., 1993). 

Skiba, P. J. and Jackson, L.L. (1993). (Z)-10-Heptadecen-2-one and 2-tridecanone biosynthesis from [l-14C]acetate by Drosophila buzzatii. Insect Biochem. Mol. 

Southern corn rootworm. The structure of the southern corn rootworm has been defined as 10-methyl 2-tridecanone, XI (Figure 16) (5J3). Alkylation of undecanoic acid with n-propyl bromide was followed by conversion to the diastereomeric amides with either (S)- or (R)-a-methylbenzylamine that had been purified previously by recrystallization of D and L tartaric acid salts, respectively. Recrystallizations of these amides from ethanol (4 was sufficient) gave 32% yields of pure (>99.5%) diastereo-mers (Figure 16). Hydroxyethylation labilized the amides toward hydrolysis. It was convenient to intercept the aminoesters and reduce them with LAH. The resulting carbinols were than carried forward in standard manner to provide the ketones. 

---