Design, Synthesis, and Biological Evaluation of Pyrido [1,2-α] Pyrimidinone Mesoionic Derivatives Bearing Propenylbenzene as the Vector Control Insecticide.

A series of novel pyrido [1,2-α] pyrimidinone mesoionic derivatives bearing a propenylbenzene group at the 1-position were synthesized on the basis of the structure of mesoionic insecticides triflumezopyrim and dicloromezotiaz via a rationally conceived pharmacophore model and evaluated for their insecticidal activities against three insect vectors. The bioassay results showed that some compounds exerted remarkable insecticidal activities against , , and . Particularly, compound displayed outstanding insecticidal activity against , with an LC value of 0.

Serotonin modulates insect gut bacterial community homeostasis.

Background: Metazoan guts are in permanent contact with microbial communities. However, the host mechanisms that have developed to manage the dynamic changes of these microorganisms and maintain homeostasis remain largely unknown.

Results: Serotonin (5-hydroxytryptamine [5-HT]) was found to modulate gut microbiome homeostasis via regulation of a dual oxidase (Duox) gene expression in both Bactrocera dorsalis and Aedes aegypti.

Sodium channel activation underlies transfluthrin repellency in Aedes aegypti.

Background: Volatile pyrethroid insecticides, such as transfluthrin, have received increasing attention for their potent repellent activities in recent years for controlling human disease vectors. It has been long understood that pyrethroids kill insects by promoting activation and inhibiting inactivation of voltage-gated sodium channels. However, the mechanism of pyrethroid repellency remains poorly understood and controversial.

Multiple insecticide resistance and associated mechanisms to volatile pyrethroid in an Aedes albopictus population collected in southern China.

Conventional and volatile pyrethroids are widely used to control the vectors of dengue arboviral diseases, Aedes albopictus in China. The development of resistance to conventional pyrethroids has become an increasing problem, potentially affecting the use of volatile pyrethroid. The Ae.

Discovery of a Novel Series of Tricyclic Oxadiazine 4a-Methyl Esters Based on Indoxacarb as Potential Sodium Channel Blocker/Modulator Insecticides.

Indoxacarb, a commercialized oxadiazine insecticide, nearly irreversibly blocks open/inactivated, but not resting sodium channels. The structure-activity relationships showed that the substituents at the position of the chiral atom in the oxadiazine ring are very important to the biological activity of oxadiazine insecticide. Here we synthesized a series of tricyclic oxadiazine 4a-methyl ester derivatives.

Identification and functional characterization of D-fructose receptor in an egg parasitoid, Trichogramma chilonis.

In insects, the gustatory system has a critical function not only in selecting food and feeding behaviours but also in growth and metabolism. Gustatory receptors play an irreplaceable role in insect gustatory signalling. Trichogramma chilonis is an effective biocontrol agent against agricultural insect pests.

Resistance to insecticides and synergistic and antagonistic effects of essential oils on dimefluthrin toxicity in a field population of Culex quinquefasciatus Say.

In this work, we firstly tested five spatial repellent pyrethroids, meperfluthrin, dimefluthrin, heptafluthrin, metofluthrin and transfluthrin, to determine the susceptibility of pyrethroids to field strains of Culex quinquefasciatus using adult topical bioassay. The results showed that though field strains exhibited the highest resistance to dimefluthrin among the selected five pyrethroids, it still can be considered low resistance in the scale of Cui et al. (2006; 2007).

Thioether-bridged arylalkyl-linked N-phenylpyrazole derivatives: Design, synthesis, insecticidal activities, structure-activity relationship and molecular-modeling studies.

Owing to thioether diverse physicochemical properties by non-covalent interactions with bio-macromolecules, thioether derivatives containing heterocyclic moiety are known for their interesting insecticidal bioactivities and attracting considerable attention as neuroactive insecticides. Here we synthesis a series of novel thioether bridged N-phenylpyrazole derivatives incorporating various (hetero)aromatic substituents into 4-position of the pyrazole ring. Structure-activity relationship (SAR) studies resulted in compounds 6d and 7d with the most potent insecticidal activity among the series containing various substituted benzene substituents (LC = 13.

Access to Densely Functionalized Chalcone Derivatives with a 2-Pyridone Subunit via Pd/Cu-Catalyzed Oxidative Furan-Yne Cyclization of N-(2-Furanylmethyl) Alkynamides under Air.

A protocol for synthesis of chalcone derivatives with a 2-pyridone subunit from N-(2-furanylmethyl) alkynamides is reported. This synthesis involves Pd/Cu-catalyzed oxidative furan-yne cyclization at room temperature in air and may proceed via nucleopalladation of the alkyne to form a vinylpalladium intermediate, with a furan ring acting as the nucleophile.

The Receptor Site and Mechanism of Action of Sodium Channel Blocker Insecticides.

Sodium channels are excellent targets of both natural and synthetic insecticides with high insect selectivity. Indoxacarb, its active metabolite DCJW, and metaflumizone (MFZ) belong to a relatively new class of sodium channel blocker insecticides (SCBIs) with a mode of action distinct from all other sodium channel-targeting insecticides, including pyrethroids. Electroneutral SCBIs preferably bind to and trap sodium channels in the inactivated state, a mechanism similar to that of cationic local anesthetics.

Mutations in the transmembrane helix S6 of domain IV confer cockroach sodium channel resistance to sodium channel blocker insecticides and local anesthetics.

Indoxacarb and metaflumizone are two sodium channel blocker insecticides (SCBIs). They preferably bind to and trap sodium channels in the slow-inactivated non-conducting state, a mode of action similar to that of local anesthetics (LAs). Recently, two sodium channel mutations, F1845Y (F(4i15)Y) and V1848I (V(4i18)I), in the transmembrane segment 6 of domain IV (IVS6), were identified to be associated with indoxacarb resistance in Plutella xylostella.

Design, synthesis and structure-activity relationship of indoxacarb analogs as voltage-gated sodium channel blocker.

Indoxacarb, the first commercialized pyrazoline-type sodium-channel blocker, is a commonly used insecticide because of high selectivity. To discover sodium-channel blocker with high insecticidal activity, a series of novel indoxacarb analogs were designed and synthesized by judicious structural modifications of the substituent group of C5, C6 in indenone and C'4 in benzene ring. Some analogs exhibited significant insecticidal activities against Spodoptera litura F.

Discovery of a novel series of phenyl pyrazole inner salts based on fipronil as potential dual-target insecticides.

A series of novel phenyl pyrazole inner salt derivatives based on fipronil were designed and synthesized in the search for dual-target insecticides. These compounds were designed to target two families of nicotinic acetylcholine receptors and γ-aminobutyric acid receptors. The insecticidal activities of the new compounds against diamondback moth (Plutella xylostella) were evaluated.

Synthesis and photoactivated insecticidal activity of tetraethynylsilanes.

A series of tetraethynylsilanes (TETS) have been synthesized by reaction of silicon tetrachloride (SiCl(4)) with Ar-C triple bond CLi, which was prepared in situ by treatment of Ar-C triple bond CH with n-BuLi. For these TETS thus prepared, their photoactivated insecticidal activities against the 4th-instar larvae of Aedes albopictus (Skuse) were evaluated to enrich the structure-activity relationship. In particular, compound 8 exhibited excellent photoactivated insecticidal activity, the LC(50) value was 0.

1-[2,6-Dichloro-4-(trifluoro-meth-yl)phen-yl]-5-iodo-4-trifluoro-methyl-sulfinyl-1H-pyrazole-3-carbonitrile.

In the title compound, C(12)H(2)Cl(2)F(6)IN(3)OS, the dihedral angle between the planes of the benzene and pyrazole rings is 77.8 (2)°. In the crystal, a short I⋯N contact of 2.