Divergent Electrochemical Carboamidation of Cyclic Amines.

We developed an electrochemical carboamidation sequence that affords either cyclic ß-amidoamine products via direct functionalization or linear hydroxybisamide products via a ring opening pathway. The reaction pathway was dependent on the nature of the N-acyl activating group, with carbamate groups favoring direct isocyanide addition to the N-acyliminium ion intermediate and the benzoyl activating group favoring the ring opening-functionalization pathway. Both protocols are one-pot reaction sequences, have general applicability, and lead to peptide-like products of greatly increased molecular complexity.

Natural alleles of a uridine 5'-diphospho-glucosyltransferase gene responsible for differential endosperm development between upland rice and paddy rice.

Traditional upland rice generally exhibits insufficient grains resulting from abnormal endosperm development compared to paddy rice. However, the underlying molecular mechanism of this trait is poorly understood. Here, we cloned the uridine 5'-diphospho (UDP)-glucosyltransferase gene EDR1 (Endosperm Development in Rice) responsible for differential endosperm development between upland rice and paddy rice by performing quantitative trait loci analysis and map-based cloning. EDR1 was highly expressed in developing seeds during grain filling. Natural variations in EDR1 significantly reduced the UDP-glucosyltransferase activity of EDR1YZN compared to EDR1YD1 , resulting in abnormal endosperm development in the near-isogenic line, accompanied by insufficient grains and changes in grain quality. By analyzing the distribution of the two alleles EDR1YD1 and EDR1YZN among diverse paddy rice and upland rice varieties, we discovered that EDR1 was conserved in upland rice, but segregated in paddy rice. Further analyses of grain chalkiness in the alleles of EDR1YD1 and EDR1YZN varieties indicated that rice varieties harboring EDR1YZN and EDR1YD1 preferentially showed high chalkiness, and low chalkiness, respectively. Taken together, these results suggest that the UDP-glucosyltransferase gene EDR1 is an important determinant controlling differential endosperm development between upland rice and paddy rice.

Stereodivergent Pd/Cu catalysis: asymmetric alkylation of racemic symmetrical 1,3-diphenyl allyl acetates.

We report a stereodivergent Pd/Cu catalyst system that was successfully applied to the asymmetric allylic alkylation of symmetrical 1,3-disubstituted allyl acetates with prochiral imino esters, providing efficient access to enantiopure products bearing vicinal stereocenters in a fully stereodivergent manner. The protocol proceeds smoothly under mild reaction conditions and can accommodate a range of imino esters, delivering the substituted products in high yields and with excellent diastereoselectivities (up to >20 : 1 dr) and enantioselectivities (up to >99% ee).

Stereodivergent Pd/Cu Catalysis for the Dynamic Kinetic Asymmetric Transformation of Racemic Unsymmetrical 1,3-Disubstituted Allyl Acetates.

A stereodivergent Pd/Cu catalyst system has been developed for the unprecedented dynamic kinetic asymmetric transformation (DyKAT) of racemic unsymmetrical 1,3-disubstituted allylic acetates with prochiral aldimine esters. A series of α,α-disubstituted α-amino acids bearing vicinal stereocenters were easily prepared with excellent enantioselectivities (up to >99% ee) and diastereoselectivities (up to >20:1 dr). Moreover, all four stereoisomers of the product can be readily obtained simply by switching the configurations of the two chiral metal catalysts. Furthermore, the present work highlights the power of synergistic Pd/Cu catalysis consisting of two common bidentate chiral ligands for stereodivergent synthesis.

Enantioselective Rhodium-Catalyzed Dearomative Arylation or Alkenylation of Quinolinium Salts.

A highly enantioselective rhodium(I)-catalyzed dearomative arylation or alkenylation of easily available N-alkylquinolinium salts is reported, thus providing an effective and practical approach to the synthesis of dihydroquinolines in up to 99 % ee. This reaction tolerates a wide range of functional groups with respect to both the organic boronic acids and the quinoline starting materials. Moreover, the synthetic utility of this protocol is demonstrated in the formal asymmetric synthesis of bioactive tetrahydroquinoline and the total syntheses of (-)-angustureine and (+)-cuspareine.

Hydrophobic modification of cellulose nanofibers by gallic acid and the application in pressure sensing.

Via rational molecular structure design and using gallic acid (GA) for hydrophobic modification of cellulose nanofibers (CNF), the "polymer dipole" CNF-GA with hydrophilic main chains and hydrophobic side chains was prepared, which improved the poor piezoelectric properties of CNF used for preparing pressure sensors. Due to the appearance of the side chains, the elongation at break of the CNF-GA-2, compared with CNF, was enhanced by 186 %, and the excellent tensile strength, puncture load, and tearing strength were displayed. Moreover, the significant glass transition temperature (Tg) near the human body temperature was exhibited for CNF-GA, making it possible to be applied in temperature sensing. Most importantly, the CNF-GA-2 showed the maximum hydrophobicity, with a contact angle of 76.77°. Finally, the CNF-GA-2/MXene nanocomposite film was prepared by the CNF-GA-2 with MXene through vacuum filtration. The results indicated that the film had excellent piezoelectric properties (d33 = 63.283), the generated stable induced voltage (125.6 mV), the preferable piezoresistive performance (ΔR/R0 = 2.15), the fast response/recovery time (48/61 ms), which could achieve dynamic and static responses. Moreover, this film could be used for real-time detection of limb movements (such as wrists).

Constructing a 3D Ion Transport Channel-Based CNF Composite Film with an Intercalated Structure for Superior Performance Flexible Supercapacitors.

The weak stiffness, huge thickness, and low specific capacitance of commonly utilized flexible supercapacitors hinder their great electrochemical performance. Learning from a biomimetic interface strategy, we design flexible film electrodes based on functional intercalated structures with excellent electrochemical properties and mechanical flexibility. A composite film with high strength and flexibility is created using graphene (reduced graphene oxide (rGO)) as the plane layer, layered double metal hydroxide (LDH) as the support layer, and cellulose nanofiber (CNF) as the connection agent and flexible agent. The interlayer height can be adjusted by the ion concentration. The highly interconnected network enables excellent electron and ion transport channels, facilitating rapid ion diffusion and redox reactions. Moreover, the high flexibility and mechanical properties of the film achieve multiple folding and bending. The CNF-rGO-NiCoLDH film electrode exhibits high capacitance performance (3620.5 mF cm-2 at 2 mA cm-2), excellent mechanical properties, and high flexibility. Notably, flexible all-solid assembled CNF-rGO-NiCoLDH//rGO has an extremely high area energy density of 53.5 mWh cm-2 at a power density of 1071.2 mW cm-2, along with cycling stability of 89.8% retention after 10 000 charge-discharge cycles. This work provides a perspective for designing high-performance energy storage materials for flexible electronics and wearable devices.

Synthesis of axially chiral oxazoline-carbene ligands with an N-naphthyl framework and a study of their coordination with AuCl·SMe(2).

Axially chiral oxazoline-carbene ligands with an N-naphthyl framework were successfully prepared, and their coordination behavior with AuCl·SMe(2) was also investigated, affording the corresponding Au(I) complexes in moderate to high yields.

Identification and fine mapping of rtms1-D, a gene responsible for reverse thermosensitive genic male sterility from Diannong S-1X.

Thermosensitive genic male sterility (TGMS) has been widely used in two-line hybrid rice breeding. Due to hybrid seed production being highly affected by changeable environments, its application scope is limited to some extent. Thus, it is of great importance to identify potential TGMS genes in specific rice varieties. Here, Diannong S-1 xuan (DNS-1X), a reverse TGMS (RTGMS) japonica male sterile line, was identified from Diannong S-1. Genetic analysis showed that male sterility was tightly controlled by a single recessive gene, which was supported by the phenotype of the F1 and F2:3 populations derived from the cross between DNS-1X and Yunjing 26 (YJ26). Combining simple sequence repeat (SSR) markers and bulked segregation analysis (BSA), we identified a 215 kb region on chromosome 10 as a candidate reverse TGMS region, which was designated as rtms1-D. It was narrower than the previously reported RTGMS genes rtms1 and tms6(t). The fertility conversion detected in the natural environment showed that DNS-1X was sterile below 28-30 °C; otherwise, it was fertile. Histological analysis further indicated that the pollen abortion was occurred in the young microspore stage. This study will provide new resources for two-line hybrid rice and pave the way for molecular breeding of RTGMS lines.

Discovery and Optimization of Pyrrolopyrimidine Derivatives as Selective Disruptors of the Perinucleolar Compartment, a Marker of Tumor Progression toward Metastasis.

The perinucleolar compartment (PNC) is a dynamic subnuclear body found at the periphery of the nucleolus. The PNC is enriched with RNA transcripts and RNA-binding proteins, reflecting different states of genome organization. PNC prevalence positively correlates with cancer progression and metastatic capacity, making it a useful marker for metastatic cancer progression. A high-throughput, high-content assay was developed to identify novel small molecules that selectively reduce PNC prevalence in cancer cells. We identified and further optimized a pyrrolopyrimidine series able to reduce PNC prevalence in PC3M cancer cells at submicromolar concentrations without affecting cell viability. Structure-activity relationship exploration of the structural elements necessary for activity resulted in the discovery of several potent compounds. Analysis of in vitro drug-like properties led to the discovery of the bioavailable analogue, metarrestin, which has shown potent antimetastatic activity with improved survival in rodent models and is currently being evaluated in a first-in-human phase 1 clinical trial.

Cu(I)-catalyzed asymmetric chlorination of ß-keto esters in the presence of chiral phosphine-Schiff base type ligands.

Chiral phosphine-Schiff base type ligand L8 prepared from (R)-(-)-2-(diphenylphosphino)-1,1'-binaphthyl-2'-amine was found to be a fairly effective ligand for Cu(I)-promoted enantioselective chlorination of ß-keto esters to give the corresponding products in high yields and with moderate enantioselectivities.

Synthesis of chiral mono(N-heterocyclic carbene) palladium and gold complexes with a 1,1'-biphenyl scaffold and their applications in catalysis.

Axially chiral mono(NHC)-Pd(II) and mono(NHC)-Au(I) complexes with one side shaped 1,1'-biphenyl backbone have been prepared from chiral 6,6'-dimethoxybiphenyl-2,2'-diamine. The complexes were characterized by X-ray crystal structure diffraction. The Pd(II) complex showed good catalytic activities in the Suzuki-Miyaura and Heck-Mizoroki coupling reactions, and the (S)-Au(I) complexes also showed good catalytic activities in the asymmetric intramolecular hydroamination reaction to give the corresponding product in moderate ee.

Palladium-Catalyzed Decarboxylative Asymmetric Allylic Alkylation of Dihydroquinolinones.

A palladium-catalyzed decarboxylative asymmetric allylic alkylation (Pd-DAAA) of benzo-fused and non-benzo-fused δ-valerolactams is disclosed. This methodology gives access to chiral lactams bearing C3-quaternary stereocenters, which are central to many natural products and biologically active compounds. The reaction proceeds via palladium-catalyzed ionization of an allyl ester, followed by carbon dioxide extrusion and recombination of the electrophilic Pd-π-allyl complex with the in situ generated lactam enolate. This final step converts racemic allylic ester starting materials into enantiomerically enriched substituted lactams with high yield and enantiomeric excess.

Phosphine-catalyzed annulation of ethyl (arylimino)acetates: synthesis of highly functionalized oxoimidazolidines.

This paper describes an unexpected and novel nucleophilic phosphine-catalyzed annulation of ethyl (arylimino)acetates to give polysubstituted oxoimidazolidine derivatives in moderate to good yields from simple and easily available starting materials under mild conditions. In this reaction, the addition of methyl vinyl ketone (MVK) is essential to induce the formation of oxoimidazolidines.

Biomass-based magnetic fluorescent nanoparticles: One-step scalable synthesis, application as drug carriers and mechanism study.

A biomass-based magnetic fluorescent nanoparticle (MFNPs) was successively in situ synthesized via a one-step high-gravity approach, which constructed by a magnetic core of Fe3O4 nanoparticles, the fluorescent marker of carbon dots (CDs), and shells of chitosan (CS). The obtained MFNPs had a 10 nm average diameter and narrow particle size distribution, low cytotoxicity, superior fluorescent emission and superparamagnetic properties. The encapsulating and release 5-fluorouracil experiments confirmed that the introduction of CS/CDs effectively improved the drug loading capacity. Mechanism and kinetic studies proved that: (i) the monolayer adsorption was the main sorption mode under the studied conditions; (ii) the whole adsorption process was controlled by intra-liquid diffusion mass transfer and governed by chemisorption; and (iii) the release process was controlled by Fickian diffusion. These results demonstrated this method to one-step continuously produce MFNPs and the construction of non-toxic nanostructure possessed great superiority in currently Nano-delivery systems, which would show high application value in targeted drug delivery, magnetic fluid hyperthermia treatment, magnetic resonance imaging (MRI), in vitro testing and relative research.

Chitosan and carboxymethyl cellulose-multilayered magnetic fluorescent systems for reversible protein immobilization.

Magnetic fluorescent nanoparticles (MFNPs)-based protein immobilization systems were successfully synthesized via a layer-by-layer (LbL) assembly approach in an impinging stream-rotating packed bed, which adopted chitosan containing carbon dots (CDs)@Fe3O4 nanoparticles (NPs) as a precursor, chitosan (CS) or carboxymethylcellulose (CMC) involving CDs as shells. To reveal the relationship between structure and efficiency of systems, the effect of self-assembly mode and layer number\was investigated to provide us insight into how to improve the design of MFNPs-based supports. Finally, an MFNPs-based protein immobilization system with excellent fluorescence and magnetic response, expanded specific surface area, and enhanced immobilization and release performance were obtained. Immobilization mechanism and kinetic studies were also conducted to reveal the rate-controlling step and the template affinity. Taken together, this study provides an effective strategy to synthesize bifunctional MFNPs and to adjust the performance, which aims for facilitating new possibilities for biomass-based nanomaterials used for protein immobilization.

CQDs-Doped Magnetic Electrospun Nanofibers: Fluorescence Self-Display and Adsorption Removal of Mercury(II).

This paper reports the carbon quantum dots-doped magnetic electrospinning nanofibers for the self-display and removal of Hg(II) ions from water. The fluorescent carbon quantum dots and magnetic Fe3O4 nanoparticles were pre-prepared successfully, and they appeared to be homogeneously dispersed in nanofibers via electrospinning. During the sorption of Hg(II) ions, the significant fluorescence signals of nanofibers gradually declined and exhibited a good linear relationship with cumulative adsorption capacity, which could be easily recorded by the photoluminescence spectra. The sorption performance of mercury ions onto the nanofibers was investigated in terms of different experimental factors including contact time, solution pH value, and initial ion concentration. Considering the actual parameters, the nanofibers were sensitive self-display adsorption system for Hg(II) ions in the existence of other cation. The sorption data were described by different kinetic models, which indicate that the whole sorption was controlled by chemical adsorption. The intraparticle diffusion mass transfer was not obvious in this system, which further proved the uniform adsorption and even fluorescence quenching in nanofibers. Additionally, the nanocomposite fiber could regenerate in several cycles with no significant loss of adsorption capacity and fluorescence intensity. Thus, the nanofibers are promising alternatives for environmental pollution incidents. It is especially competent due to its high efficiency for self-display and removal of high concentration of mercury ions.

Enhanced electrochemical properties of LiFePO4 (LFP) cathode using the carboxymethyl cellulose lithium (CMC-Li) as novel binder in lithium-ion battery.

Novel water-based binder CMC-Li is synthesized using cotton as raw material. The mechanism of the CMC-Li as a binder is reported. Electrochemical properties of batteries cathodes based on commercially available lithium iron phosphate (LiFePO4, LFP) and CMC-Li as a water-soluble binder are investigated. CMC-Li is a novel lithium-ion binder. Compare with conventional poly(vinylidene fluoride) (PVDF) binder, and the battery with CMC-Li as the binder retained 97.8% of initial reversible capacity after 200 cycles at 176 mAh g(-1), which is beyond the theoretical specific capacity of LFP. Constant current charge-discharge test results demonstrate that the LFP electrode using CMC-Li as the binder has the highest rate capability, follow closely by that using PVDF binder. The batteries have good electrochemical property, outstanding pollution-free and excellent stability.

Novel polymer Li-ion binder carboxymethyl cellulose derivative enhanced electrochemical performance for Li-ion batteries.

Novel water-based binder lithium carboxymethyl cellulose (CMC-Li) is synthesized by cotton as raw material. The mechanism of the CMC-Li as a binder is reported. Electrochemical properties of batteries' cathodes based on commercially available lithium iron phosphate (LiFePO4, LFP) and water-soluble binder are investigated. Sodium carboxymethyl cellulose (CMC-Na, CMC) and CMC-Li are used as the binder. After 200 cycles, compared with conventional poly(vinylidene fluoride) (PVDF) binder, the CMC-Li binder significantly improves cycling performance of the LFP cathode 96.7% of initial reversible capacity achieved at 175 mA h g(-1). Constant current charge-discharge test results demonstrate that the LFP electrode using CMC-Li as the binder has the highest rate capability, followed closely by those using CMC and PVDF binders, respectively. Electrochemical impedance spectroscopy test results show that the electrode using CMC-Li as the binder has lower charge transfer resistance than the electrodes using CMC and PVDF as the binders.

Study on novel functional materials carboxymethyl cellulose lithium (CMC-Li) improve high-performance lithium-ion battery.

Novel cellulose derivative CMC-Li was synthesized by cotton as raw material. The mechanism of the CMC-Li modified electrode materials by electrospinning was reported. CMC-Li/lithium iron phosphate (LiFePO4, LFP) composite fiber coated with LFP and CMC-Li nanofibers was successfully obtained by electrospinning. Then, CMC-Li/LFP nano-composite fiber was carbonized under nitrogen at a high temperature formed CNF/LFP/Li (CLL) composite nanofibers as cathode material. It can increase the contents of Li+, and improving the diffusion efficiency and specific capacity. The battery with CLL as cathode material retained close to 100% of initial reversible capacity after 200 cycles at 168 mAh g(-1), which was nearly the theoretical specific capacity of LFP. The cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), X-ray diffraction (XRD) and scanning electron microscope (SEM) were characterizing material performance. The batteries have good electrochemical property, outstanding pollution-free, excellent stability.