Lactones 46. Synthesis, antifeedant and antibacterial activity of γ-lactones with a p-methoxyphenyl substituent.

BACKGROUND: Lactones are well known for their biological activity. Grosheimin and repin are potent deterrents against storage pests. The unsaturated lactones have exhibited a wide spectrum of antibacterial activity. In our study we focused on the synthesis and evaluation of the biological activity of anisaldehyde derivatives containing lactone function. RESULTS: Four new lactones were synthesized in one-step reductive dehalogenation or dehydrohalogenation reactions. These compounds, together with halolactones synthesized earlier, were tested for their antifeedant activity towards Sitophilus granaries, Trogoderma granarium and Tribolium confusum. The results of the tests showed that the highest activity, comparable with that of azadirachtin, towards all tested pests (total coefficient of deterrence 143.3-183.9) was observed for lactone with a vinyl substituent. The antibacterial activity of these compounds was also evaluated. The most potent lactone was active towards gram-positive bacteria strains. CONCLUSIONS: The results of biological tests showed that halogen atom removal significantly increased the antifeedant properties of γ-lactones with a p-methoxyphenyl substituent. Unsaturated lactones are most promising in the context of their possible industrial application as crop protection agents. Further structural modifications of lactones with aromatic rings are needed to find important structural factors increasing the antibacterial activity.

Lactones 43. New biologically active lactones: ß-cyclocitral derivatives.

BACKGROUND: In our previous studies bicyclic γ-lactones with cyclohexane ring exhibited high antifeedant activity against storage pests. The activity was correlated with the type and number of substituents in the cyclohexane ring. One of the most potent group of antifeedant agents was δ-iodo-γ-lactones. RESULTS: We present the synthesis of new bicyclic γ-lactones with the cyclohexane ring containing different halogen atoms. To determine the impact of halogen type on biological activity the lactone without halogen atom was also synthesized. The lactones were tested for their antifeedant activity toward the granary weevil beetle (Sitophilus granarius L.), the khapra beetle (Trogoderma granarium Everts) and the confused flour beetle (Tribolium confusum Du Val.). The results of the tests proved that the highest activity was observed for chlorolactone (7) towards larvae and adults of Tribolium confusum. Antibacterial activity of new lactones was also evaluated. Lactone without halogen atom (8) was active against Staphylococcus aureus and Listeria monocytogenes. CONCLUSIONS: Studies on the biological activity of synthesised lactones revealed high selectivity towards insect pests as well as bacterial strains. Only the halolactones exhibited significant antifeedant activity. In contrast, antibacterial activity was shown only by the lactone (8) without halogen.

Long-alkyl-chain quaternary ammonium lactate based ionic liquids.

A new group of quaternary ammonium lactate based ionic liquids have been prepared and characterized. Didecyldimethylammonium (DDA) and benzalkonium (BA) D,L- and L-lactates are air-stable, hydrophilic, surface-active salts. They are very effective antibacterial and antifungal agents, especially the DDA lactates, against Streptococcus mutants and Candida albicans. Their activities are comparable or more effective than the original benzalkonium chloride. In addition, they have been shown to be good insect-feeding deterrents. However, they are poor antifungal agents for wood preservation. The toxicity of the DDA and BA lactates has also been studied and the results are presented in this paper.

Choline-derivative-based ionic liquids.

A total of sixty-three choline derivative-based ionic liquids in the forms of chlorides, acesulfamates, and bis(trifluoromethylsulfonyl)imides have been prepared and their physical properties (density, viscosity, solubility, and thermal stability) have been determined. Thirteen of these salts are known chlorides: precursors to the 26 water-soluble acesulfamates, 12 acesulfamates only partially miscible with water, and 12 water-insoluble imides. The crystal structures for two of the chloride salts-(2-hydroxyethyl)dimethylundecyloxymethylammonium chloride and cyclododecyloxymethyl(2-hydroxyethyl)dimethylammonium chloride-were determined. The antimicrobial (cocci, rods, and fungi) activities of the new hydrophilic acesulfamate-based ILs were measured and 12 were found to be active. The alkoxymethyl(2-hydroxyethyl)dimethylammonium acesulfamates have been shown to be insect feeding deterrents and thus open up a new generation of synthetic deterrents based on ionic liquids. The alkoxymethyl(2-decanoyloxyethyl)dimethylammonium bis(trifluoromethylsulfonyl)imides have also been shown to act as fixatives for soft tissues and can furthermore be used as substitutes for formalin and also preservatives for blood.

Identification of the cuticular lipid composition of the Western Flower Thrips Frankliniella occidentalis.

The Western Flower Thrips Frankliniella occidentalis effectively resists many insecticides, but it can be controlled by the use of bioinsecticides such as entomopathogenic fungi. The epicuticular chemistry of these insects is therefore of great interest, and accordingly, the cuticular lipid composition of F. occidentalis was analysed. It was found that the cuticular lipids of both the adult and larval stages of F. occidentalis consist of two groups of compounds--hydrocarbons and free fatty acids. The same hydrocarbon pattern was found in both adults and larvae, with the exception of n-hentriacontane, which was detected only in adult insects. The following homologous series were identified: n-alkanes from C-25 to C-29 (31) with the marked dominance of odd numbers of carbon atoms, 3-methylalkanes with 26 and 28 carbon atoms, and branched monomethylalkanes (branched at C-9, -11, -13 and -15) with 26, 28 and 30 carbon atoms. The chemical composition of the free fatty acids consists of two homologous series: saturated (C(14:0), C(16:0), C(18:0)) and unsaturated fatty acids (C(16:1) and C(18:1)). This analysis confirmed the lack of potential inhibitors of entomopathogenic fungi in the cuticular lipids of this insect species.

Synthesis and insect antifeedant activity of precocene derivatives with lactone moiety.

Starting from precocenes I and II, four of their derivatives with a lactone moiety were obtained. The compounds have been assessed as antifeedants against several diverse insect species including the storage pests the confused flour beetle (Tribolium confusum Duv., larvae and adults), the granary weevil beetle (Sitophilus granarius L., adults), and the khapra beetle (Trogoderma granarium Ev., larvae) and against the herbivorous pest insects Colorado potato beetle (Leptinotarsa decemlineata Say, adults and larvae) and aphids (Myzus persicae Sulz.). Precocenes, especially precocene II, showed a very strong antifeedant effect against all storage pests and aphids. The introduction of a lactone moiety caused a decrease in antifeedant activity against these species. Both precocenes were moderately active against L. decemlineata adults. The best antifeedants to this species were precocene derivatives, especially iodolactones. The introduction of iodine into a molecule had a great effect on the antifeedant activity of those compounds.