Lewis Acid Regulation Strategy for Constructing D-A-A Covalent Organic Frameworks with Enhanced Photocatalytic Organic Conversion.

Owing to their excellent photoelectric properties, donor-acceptor (D-A) type photocatalytic covalent organic frameworks (COFs) have attracted significant research interest in recent years. However, the limited D-A structural units of existing COFs restrict the development of novel and efficient photocatalytic COF materials. To solve this problem, we developed a series of D-A-A-type COFs utilizing a Lewis acid regulation strategy, in which Lewis acids act as the coordination centers, and pyridine and cyano groups act as ligands.

Donor-acceptor type COFs with multiple fluorine groups as electron storage units to promote antimicrobial performance.

The novel donor-acceptor (D-A) type covalent organic frameworks TATF-COF and TATP-COF, with multiple fluorine groups as electron storage units, were successfully constructed to achieve efficient charge transfer and photocatalytic activity for antibacterial photocatalytic therapy. Fluorine, the most electronegative element, was utilized as an electron-withdrawing substituent for the acceptor, which could unite the donor unit together and efficiently improve the charge transfer from the donor to acceptor. The unique D-A structures of TATF-COF and TATP-COF ensure that they have narrow band gaps, strong photocurrent responses, long fluorescence lifetimes, and good capacity to generate reactive oxygen species (ROS) to realize good antibacterial activity.

Photocatalyzed C3-H Nitrosylation of Imidazo[1,2-]pyridine under Continuous Flow and External Photocatalyst-, Oxidant-, and Additive-Free Conditions.

This study reports a protocol for the highly regioselective photocatalyzed C-H nitrosylation of imidazo[1,2-]pyridine scaffolds at the C3 position under a combination of visible-light irradiation and continuous flow without any external photocatalyst. This protocol involves mild and safe conditions and shows good tolerance to air and water along with excellent functional group compatibility and site selectivity, generating various 3-nitrosoimidazo[1,2-]pyridines in excellent yields under photocatalyst-, oxidant-, and additive-free conditions.Notably, the proposed nitrosylation reaction, which introduces the chromophore NO into imidazo[1,2-]pyridine scaffolds, occurs efficiently under visible-light irradiation without any additional photocatalyst owing to the intense light-absorption characteristics of the nitrosylation products.

Chromosome-level genomes of two armyworms, Mythimna separata and Mythimna loreyi, provide insights into the biosynthesis and reception of sex pheromones.

Mythimna separata and Mythimna loreyi are global pests of gramineous cereals, heavily controlled with synthetic insecticides. Here, we generated two high-quality chromosome-level genome assemblies for M. separata (688 Mb) and M.

Fluorinated covalent organic frameworks for efficient drug delivery.

In this study, two novel fluorine-functionalized crystalline covalent organic frameworks (COFs), namely DF-TAPB-COF and DF-TATB-COF, were synthesized, and their ordered structure, porosity, suitable pore size, and abundant fluorine groups were expected to serve as effective carriers in drug delivery. The excellent cell viability of DF-TAPB-COF and DF-TATB-COF was verified using MTT assays. Both COFs exhibited very high loading capacities in terms of drug loading performance, in particular the drug loading rate of DF-TAPB-COF for 5-fluorouracil (5-FU) was up to 69%.

Accumulation of Sulfonic Acid Groups Anchored in Covalent Organic Frameworks as an Intrinsic Proton-Conducting Electrolyte.

Covalent organic frameworks (COFs) are a novel class of crystalline porous polymers, which possess high porosity, excellent stability, and regular nanochannels. 2D COFs provide a 1D nanochannel to form the proton transport channels. The abovementioned features afford a powerful potential platform for designing materials as proton transportation carriers.

Fine Structure and Olfactory Reception of the Labial Palps of .

The olfactory system of insects is essential in many crucial behaviors, such as host seeking, mate recognition, and locating oviposition sites. Lepidopteran moths possess two main olfactory organs, including antennae and labial palps. Compared to antennae, the labial palps are relatively specific and worthy of further investigation due to the labial-palp pit organ (LPO), which contains a large number of sensilla located on the tip segment.

Brain Organization of : A Hemipteran Species With Prominent Antennal Lobes.

The anatomical organization of distinct regions in the insect brain often reflects their functions. In the present study, the brain structure of was examined by using immunolabeling and three-dimensional reconstruction. The results revealed the location and volume of prominent neuropils, such as the antennal lobes (AL), optic lobes (OL), anterior optic tubercles (AOTU), central body (CB), lateral accessory lobes (LAL), mushroom lobes, and distinct tritocerebral neuropils.

Central Projections of Antennal and Labial Palp Sensory Neurons in the Migratory Armyworm .

The oriental armyworm, (Walker), is a polyphagous, migratory pest relying on olfactory cues to find mates, locate nectar, and guide long-distance flight behavior. In the present study, a combination of neuroanatomical techniques were utilized on this species, including backfills, confocal microscopy, and three-dimensional reconstructions, to trace the central projections of sensory neurons from the antenna and the labial pit organ, respectively. As previously shown, the axons of the labial sensory neurons project via the ipsilateral labial nerve and terminate in three main areas of the central nervous system: (1) the labial-palp pit organ glomerulus of each antennal lobe, (2) the gnathal ganglion, and (3) the prothoracic ganglion of the ventral nerve cord.

A new approach to the asymmetric Mannich reaction catalyzed by chiral ,'-dioxide-metal complexes.

A highly efficient asymmetric Mannich-type reaction between α-tetralone-derived β-keto esters/amides and 1,3,5-triaryl-1,3,5-triazinanes was realized in the presence of chiral ,'-dioxide-Ni(ii) or Mg(ii) complex. A variety of optically active β-amino compounds with all-carbon quaternary stereocenters were obtained in good yields with excellent enantioselectivities. A possible transition state was proposed based on these experiments and previous reports.

A chiral cobalt(ii) complex catalyzed asymmetric formal [3+2] cycloaddition for the synthesis of 1,2,4-triazolines.

A highly efficient catalytic asymmetric formal [3+2] cycloaddition reaction of 5-alkoxyoxazoles with azodicarboxylate compounds has been realized by a chiral N,N'-dioxide/Co(BF)·6HO complex. A series of poly-substituted 1,2,4-triazolines compounds were obtained in moderate to excellent yields (70-99%) with excellent enantioselectivities (82-98% ee).

Catalytic asymmetric Meerwein-Ponndorf-Verley reduction of glyoxylates induced by a chiral N,N'-dioxide/Y(OTf) complex.

An asymmetric Meerwein-Ponndorf-Verley (MPV) reduction of glyoxylates was for the first time accomplished via an N,N'-dioxide/Y(OTf) complex with aluminium alkoxide and molecular sieves (MSs) as crucial additives. A variety of optically active α-hydroxyesters were obtained with excellent results. A possible reaction mechanism was proposed based on the experiments.

Chiral N,N'-Dioxide Organocatalyzed Asymmetric Electrophilic α-Cyanation of β-Keto Esters and β-Keto Amides.

An enantioselective electrophilic α-cyanation of 1-indanone-derived β-keto esters and β-keto amides using a hypervalent iodine as the cyanide-transfer reagent was realized. A chiral N,N'-dioxide was used as the efficient bifunctional organocatalyst in the presence of inorganic base, which gave the corresponding α-cyano dicarbonyl compounds in yields of 50-99% with good enantioselectivities (87-97% ee).

A global-wide search for sexual dimorphism of glomeruli in the antennal lobe of female and male Helicoverpa armigera.

By using immunostaining and three-dimensional reconstruction, the anatomical organization of the antennal lobe glomeruli of the female cotton bollworm Helicoverpa armigera was investigated. Eighty-one glomeruli were identified, 15 of which were not previously discovered. The general anatomical organization of the AL of female is similar to that of male and all glomeruli were classified into four sub-groups, including the female-specific glomerular complex, posterior complex, labial-palp pit organ glomerulus, and ordinary glomeruli.

Central Projection of Antennal Sensory Neurons in the Central Nervous System of the Mirid Bug Apolygus lucorum (Meyer-Dür).

The mirid bug Apolygus lucorum (Meyer-Dür), a polyphagous pest, is dependent on olfactory cues to locate various host plant species and mates. In this study, we traced the projection pathway of the antennal sensory neurons and visualized their projection patterns in the central nervous system of A. lucorum through confocal microscopy and digital reconstructions.

The asymmetric synthesis of polycyclic 3-spirooxindole alkaloids via the cascade reaction of 2-isocyanoethylindoles.

A highly enantioselective dearomative cascade reaction between 2-isocyanoethylindoles and 3-alkenyl-oxindoles was realized using a chiral N,N'-dioxide-Mg(II) complex catalyst. This reaction provides a straightforward access to polycyclic 3-spirooxindoles bearing cyclopenta[b]indole units with four contiguous stereocenters in excellent yields and moderate to good stereoselectivities via a Michael/Friedel-Crafts/Mannich cascade.

The synthesis of tenofovir and its analogues via asymmetric transfer hydrogenation.

A series of tenofovir analogues with potential antiviral and immunobiologically active compounds were synthesized through an asymmetric transfer hydrogenation reaction from achiral purine derivatives. Up to 97% ee and good to excellent yields were achieved under mild conditions through short reaction steps. The present report suggests an efficient process to acquire tenofovir and its analogues.