Food resources contaminated with spoilage or pathogenic microorganisms pose severe problems to all higher organisms. Here, we describe a food-hygienic strategy of the emerald cockroach wasp Ampulex compressa . The wasp larvae develop on and inside the American cockroach Periplaneta americana , a host that can harbor various putrefactive microbes, as well as human and insect pathogens. From P. americana , we isolated the Gram-negative bacterium Serratia marcescens , which is a potent entomopathogen that can rapidly kill insect larvae. It is also known as a food contaminant and as an opportunistic human pathogen. Using behavioral observations and chemical analyses, we demonstrated that A. compressa larvae impregnate their cockroach hosts from inside with large amounts of an oral secretion containing a blend of γ-lactones and isocoumarins with ( R )-(-)-mellein [( R )-(-)-3,4-diydro-8-hydroxy-3-methylisocoumarin] and micromolide [(4 R ,9 Z )-octadec-9-en-4-olide] as dominant components. We fractionated hexane extracts of the secretion and investigated the antimicrobial properties of the fraction containing the lactones and isocoumarins, as well as of synthetic ( R )-(-)-mellein and micromolide, against S. marcescens and a Gram-positive bacterium, Staphylococcus hyicus , in broth microdilution assays. The test fraction inhibited growth of both tested bacteria. The activity of the fraction against S. marcescens was explained by ( R )-(-)-mellein alone, and the activity against S. hyicus was explained by the combined action of ( R )-(-)-mellein and micromolide. Our data suggest that the specific combination of antimicrobials in the larval secretion provides an effective frontline defense against the unpredictable spectrum of microbes that A. compressa larvae may encounter during their development inside their cockroach hosts.

The first total synthesis of either enantiomer of Arteludovicinolide A and their biological evaluation is reported, featuring a new strategy for the asymmetric construction of γ-butyrolactones with stereogenic side chains in the 4-position. Starting from the renewable resource methyl 2-furoate, the sesquiterpene lactone was synthesized in 9 steps and 4.8% overall yield via an asymmetric cyclopropanation and two diastereoselective nucleophile additions making use of a donor-acceptor-cyclopropane-lactonization cascade. At noncytotoxic concentrations (≤10 μM) (+)-1 was found to have a 15 times higher anti-inflammatory activity (4.87 ± 1.1 μM) than previously reported for concentrations of ≥45 μM.

The dependence of reactivity towards hydrogen on size and morphology was studied for silver oxide Ag2O microparticles. Morphological tuning of the microparticles, which appeared in a size range from 340 to 1400 nm, was achieved in a wet‐chemical synthesis approach. Thermogravimetric measurements allowed the determination of onset temperatures and reaction rates for reduction with gaseous hydrogen as reducing agent. The results reveal the high complexity of the Ag2O reduction process, on which both the surface to volume ratio as well as the facet dependent activity of the morphologies have great influence. Differential scanning calorimetry was employed to study reduction by hydrogen, desorbing from a hydrogen‐loaded palladium foil, showing great effect of contact area size on the reactivity.

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Titanium chelate addition of aryl nucleophiles to cyclopropyl aldehyde 6 followed by a tin-catalyzed one-pot retro-aldol, acetalisation and lactonisation sequence afforded cis and trans c-aryllactone acetals. A c-furyllactone derived by this approach was further transformed in two steps to model compounds for the oxidised northeastern sectors of selected Pseudopterogorgia diterpenoids.Highly substituted g-butyrolactone motifs are profusely present in many synthetic intermediates and biologically active structures.