Selectivity of Relative Humidity Using a CP Based on S-Block Metal Ions.

Herein, we present the syntheses of a novel coordination polymer (CP) based on the perylene-3,4,9,10-tetracarboxylate (pery) linkers and sodium metal ions. We have chosen sodium metal center with the aim of surmising the effect that the modification of the metal ion may have on the relative humidity (RH) experimental measurements of the material. We confirm the role of the ions in the functionalization of the deposited layer by modifying their selectivity towards moisture content, paving the way to the generation of sensitive and selective chemical sensors.

Germacrone Derivatives as new Insecticidal and Acaricidal Compounds: A Structure-Activity Relationship.

Currently, the use of synthetic pesticides is the main method of plant protection applied in agri- and horticulture. However, its excessive use leads to the development of pesticide resistance, a contamination of the environment, toxicity to non-target organisms, and risks for human health. With the ultimate aim of contributing to the develop of a more sustainable pest management, we used the natural product germacrone (compound 1), reported to possess significant insecticidal activity, as starting material for the generation of molecular diversity (2-24). Some of the generated derivatives are natural compounds, such as 1,10-epoxygermacrone (2), 4,5-epoxygermacrone (3), gajutsulactone A (7), germacrol (11), isogermacrone (14), 9-hydroxyeudesma-3,7(11)dien-6-one (19), eudesma-4,7(11),dien-8-one (20), eudesma-3,7(11)-dien-8-one (21) and eudesma-4(15),7(11)-dien-8-one (22). Compounds, 7,11-9,10-diepoxigermacr-4,5-en-8-ol (17), 7,11-epoxieudesma-4,7(11)-dien-8-one (23) and 7,11-epoxieudesma-3,7(11)-dien-8-one (24) are described for the first time. The biocidal activity of most of these compounds was assayed against the tick Hyalomma lusitanicum. The acaricidal effects of compound 24 were four times higher than that of germacrone (1). Compound 2 is an insect antifeedant a thousand times more potent than germacrone against Rhopalosiphum padi, which makes this substance a promising selective antifeedant against this cereal pest.

Novel Insect Antifeedant and Ixodicidal Nootkatone Derivatives.

Naturally occurring nootkatone, with reported insecticidal and acaricidal properties, has been used as a lead to generate molecular diversity and, consequently, new insect antifeedant and ixodicidal compounds. A total of 22 derivatives were generated by subjecting this molecule to several reactions including dehydrogenation with the iodine/DMSO system, oxidation with SeO2, epoxidation with mCPBA, oxidation or carbon homologations of the α-carbonyl position with TMSOTf (trimethylsilyl trifluoromethanesulfonate) followed by Rubottom and Dess Martin periodane oxidations, condensation with formaldehyde using Yb(OTf)3 as catalyst and dehydroxilation using the Grieco protocol. The insect antifeedant (against Myzus persicae and Ropaloshysum padi) and ixodicidal (against the tick Hyalomma lusitanicum) activities of these compounds were tested. Compound 20 was the most active substance against M. persicae and R. padi, and twice more efficient than nootkatone in the antitick test.