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Ivorenolide B (1), anunprecedented 17-membered macrolide featuring conjugated acetylenicbonds and four chiral centers, was isolated from Khaya ivorensis. The structure of 1was fully determined by spectroscopicanalysis and total syntheses of its four most possible stereoisomers.Compound 1showed significant immunosuppressive activity. [ABSTRACT FROM AUTHOR]

An integrated asymmetric hydrogel electrolyte with a tailored composition and chemical structure on the cathode/anode-electrolyte interface is designed to boost the cost-effective, high-energy Zn-I 2 battery. Such a configuration concurrently addresses the parasitic reactions on the Zn anode side and the polyiodide shuttle issue afflicting the cathode. Specifically, the Zn 2+ -cross-linked sodium alginate and carrageenan dual network (Carra-Zn-Alg) is adopted to guide the Zn 2+ transport, achieving a dendrite-free morphology on the Zn surface and ensuring long-term stability. For the cathode side, the poly(vinyl alcohol)-strengthened poly(3,4-ethylenedioxythiophene)polystyrenesulfonate hydrogel (PVA-PEDOT) with high conductivity is employed to trap polyiodide and accelerate electron transfer for mitigating the shuttle effect and facilitating I 2 /I - redox kinetics. Attributing to the asymmetrical architecture with a customized interfacial chemistry, the optimized Zn-I 2 cell exhibits a superior Coulombic efficiency of 99.84% with a negligible capacity degradation at 0.1 A g -1 and an enhanced stability of 10 000 cycles at 5 A g -1 . The proposed asymmetric hydrogel provides a promising route to simultaneously resolve the distinct challenges encountered by the cathode and anode interfaces in rechargeable batteries.

Direct alkene C-H/N-H cross dehydrogenative coupling is an infrequent, highly challenging transformation. Herein, a photoredox radical-radical cross-coupling reaction between ketene dithioacetal as a persistent alkene radical cation and azole nitrogen center radical (NCR) was developed. This direct alkene amination proceeded through a synergistic photoredox and cobalt catalysis, with only H 2 evolution. The reaction showed excellent tolerance and highly regio- and stereospecific manner, expanding the scope of C(sp 2 )-N construction methods and radical cross-coupling modes.

Vertical distribution of phytoplankton is crucial for assessing the trophic status and primary production in inland waters. However, there is sparse information about phytoplankton vertical distribution due to the lack of sufficient measurements. Here, we report, to the best of our knowledge, the first Mie-fluorescence-Raman lidar (MFRL) measurements of continuous chlorophyll a (Chl -a ) profiles as well as their parametrization in inland water. The lidar-measured Chl -a during several experiments showed good agreement with the in situ data. A case study verified that MFRL had the potential to profile the Chl- a concentration. The results revealed that the maintenance of subsurface chlorophyll maxima (SCM) was influenced by light and nutrient inputs. Furthermore, inspired by the observations from MFRL, an SCM model built upon surface Chl -a concentration and euphotic layer depth was proposed with root mean square relative difference of 16.5% compared to MFRL observations, providing the possibility to map 3D Chl -a distribution in aquatic ecosystems by integrated active-passive remote sensing technology. Profiling and modeling Chl- a concentration with MFRL are expected to be of paramount importance for monitoring inland water ecosystems and environments.

Aluminum is an environmental neurotoxin that comes extensively in contact with human beings. Animal and human studies demonstrated that aluminum exposure increases the deposition of beta amyloid proteins in the brain as it was observed in Alzheimer's disease. The purpose of this study was to investigate whether miR-29a/b1 affected the expression of beta-secrete enzymes (BACE1) in the process of amyloid β-protein (Aβ) deposition caused by aluminum exposure. The study was performed using two different cell lines. Our results showed that after rat primary cortical neurons were exposed to aluminum, BACE1 gene and protein levels increased to different degrees, and the expression level of Aβ1-42 increased. In aluminum-exposed groups, the expression of miR-29a and miR-29b1 decreased, while the expression of amyloid protein Aβ1-42 and BACE1 increased. In miRs transfection groups, the expression of amyloid protein Aβ1-42 and BACE1 decreased. Aluminum may affect the expression of BACE1 by lowering miR-29a and miR-29b1 . AEK293 cells were utilized in this research since they present elevated levels of miR-29a and miR-29b1 . After HEK293 cells were exposed to aluminum alone, BACE1 mRNA and BACE1 protein expression levels increased with the increase of aluminum exposure dose ( p < 0.05), and the level of Aβ1-42 also increased ( p < 0.05). Compared with the group exposed to aluminum alone at the same doses, the expression levels of BACE1 mRNA and BACE1 protein in the miRs transfected plus aluminum-exposed groups significantly decreased ( p < 0.05), and the level of Aβ1-42 also decreased ( p < 0.05). This result is consistent with the investigation in rat primary neurons. The results of two types of cells showed that aluminum may cause abnormal down-regulation of the expressions of miR-29a and miR-29b1 , thus negatively regulating the increase of BACE1 expression and finally leading to the increase of Aβ.

A visible-light-induced intermolecular sulfur-alkenylation of alkenes, including both activated and unactivated alkenes, is described. This sulfur-alkenylation reaction proceed in a highly regio- and stereospecific manner involving the visible-light-induced conversion of a ketene dithioacetal to the thiavinyl 1,3-dipole intermediate, followed by a formal [3 + 2] cycloaddition and C-S bond cleavage. Furthermore, it is also an efficient approach for the late-stage functionalization of natural products and complex molecules, even being induced by sunlight under ambient conditions.

A visible-light-induced [3+2] oxidative cyclization of various alkynes with easily available ketene dithioacetals as the previously unknown thiavinyl 1,3-dipoles in the presence of an acridine photosensitizer is reported. A series of multisubstituted thiophenes were achieved regioselectively in ≤98% yields under very mild metal-free conditions without other additives. This reaction could tolerate a wide range of substrates and achieve good efficiency in large-scale syntheses. The reaction mechanism and their applications are described in detail to reveal the reactivity of the new 1,3-dipoles and the selectivity of the reactions.

Li-rich layered oxides (LLOs) are promising cathodes for lithium-ion batteries because of their high energy density provided by anionic redox. Although great improvements have been achieved in electrochemical performance, little attention has been paid to the energy density stability during fast charging. Indeed, LLOs have severe capacity fading and voltage decay especially at a high state of charge (SOC), disabling the application of the frequently used constant-current-constant-voltage mode for fast charging. Herein, we address this problem by manipulating the external electric field and tensile strain induced by lattice expansion effect in nanomaterials under the guidance of theoretical calculations, which indicate that LLOs at high SOC have almost a zero band gap and a low oxygen formation energy. This strategy will weaken polarization, stabilize lattice oxygen, and restrict phase transition simultaneously. Thus, the energy density during fast charging can be highly stabilized. Therefore, it may be of great value for the practical application of layered cathodes.

A highly concise route to substituted 1,3-dienes from vinylarenes and ketene dithioacetals under photoinduced cross-coupling reaction is described. The reaction proceeded in a highly regio- and stereoselective manner and showed broad functional group tolerance. More than 35 substituted 1,3-dienes were synthesized with good to excellent yields through the construction of the Csp 2 -Csp 2 bond without using noble metal and external oxidants, and natural sunlight could also induce the reaction to afford gram-scale synthesis under ambient conditions.

Developing highly stable materials for harmful ion detection in a water environment is of much importance and challenging. Here, two three-dimensional porous structures (termed as Eu-MOF and Tb-MOF) were successfully constructed by the strategy of anchoring Eu 3+ /Tb 3+ and rigid 1,2,4,5-benzenetetracarboxylic acid (H 4 BTEC) imidazole units (H 3 ICA) onto its frameworks. The obtained Eu-MOF and Tb-MOF display high water stability and fluorescence stability up to 30 days. Furthermore, luminescent studies reveal that Eu-MOF and Tb-MOF show rapid, recursive, and simultaneous sensing Fe 3+ and Cr 2 O 7 2- /CrO 4 2- ions in water. In addition, the sensing function possesses remarkable cyclicity and selectivity even with the existence of other analogous ions.

The suadimins A-C ( 1 - 3 ) from Melodinus suaveolens are the first example of monoterpenoid quinoline alkaloid dimers featuring an unprecedented carbon skeleton. Their structures and absolute configurations were established on the basis of extensive spectroscopic analyses, electric circular dichroism (ECD), and X-ray crystallography. Suadimin A showed significant antimycobacterial activity in vitro with an MIC 90 of 6.76 μM against the H 37 Rv strain of M. tuberculosis.

Urceoloids A (1) and B (2), two C 19 steroids with a rearranged new carbon skeleton by featuring a very unique spiro[4.4]nona-3,6,8-triene system, and a biosynthetically related known steroid (3) were isolated from Urceola quintaretii. Their structures were completely established by a combined method. A plausible biosynthetic pathway for the new carbon skeleton represented by compounds 1 and 2 was proposed. Compounds 2 and 3 showed immunosuppressive activities.

Four indole alkaloids, alstonlarsines A-D (1-4), were isolated from Alstonia scholaris and structurally characterized. Compound 1 possesses a new carbon skeleton with a cage-shaped 9-azatricyclo[4.3.1.0 3,8 ]decane motif, and compounds 2-4 feature a rare carbon skeleton that was found in nature for the first time. Plausible biosynthetic routes for 1-4 are proposed. Compound 1 showed DRAK2 inhibitory activity with an IC 50 value of 11.65 ± 0.63 μΜ.

Two luminescent lead phosphonates with two-dimensional (2D) layer and three-dimensional (3D) framework structure, namely, Pb 3 [(L 1 ) 2 (Hssc)(H 2 O) 2 ] ( 1 ) and [Pb 2 (L 2 ) 0.5 (bts)(H 2 O) 2 ]·H 2 O ( 2 ) (H 2 L 1 = O(CH 2 CH 2 ) 2 NCH 2 PO 3 H 2 , H 4 L 2 = H 2 PO 3 CH 2 NH(C 2 H 4 ) 2 NHCH 2 PO 3 H 2 , H 3 ssc = 5-sulfosalicylic acid, NaH 2 bts = 5-sulfoisophthalic acid sodium) have been prepared via hydrothermal techniques. The two compounds not only show excellent thermal stability but also remain intact in aqueous solution within an extensive pH range. Moreover, the atomic absorption spectroscopy analysis experiment indicates that there does not exist the leaching of Pb 2+ ions from the lead phosphonates, which show they are nontoxic in aqueous solution. In compound 1 , the Pb(1)O 4 , Pb(2)O 7 , Pb(3)O 4 , and CPO 3 polyhedra are interlinked into a one-dimensional chain, which is further connected to adjacent chain by sharing the Hssc 2- to form a 2D layer. Interestingly, compound 1 as a highly selective and sensitive luminescent material can be used to detect the thymine molecule with a very low detection limit of 8.26 × 10 -7 M. In compound 2 , the Pb(1)O 6 and Pb(2)O 5 polyhedra are interlinked into a dimer via edge sharing, which is further connected to adjacent dimer to form a tetramer via corner sharing, and such a tetramer is then interlinked into a 2D layer through bts 3- ligands; the adjacent 2D layers are finally constructed to a 3D structure by sharing the L 2 4- ligand. Compound 2 can be applied as an excellent luminescent sensor for sensing of VO 3 - anion. Furthermore, the probable fluorescent quenching mechanisms of the two compounds have also been studied., Competing Interests: The authors declare no competing financial interest.

A novel domino reaction of (2-iminoaryl)divinyl ketones with nitromethane was developed for the efficient synthesis of hexahydrophenanthridin-9(5H)-ones. The reaction proceeded smoothly from readily available starting materials under mild reaction conditions to construct three new bonds and two rings with high diastereoselectivities in good to excellent yields in a single step. A mechanism is proposed, involving a stepwise double Michael addition/aza-Henry reaction cascade, and in this transformation, nitromethane acts as a trinucleophile.

An unexpected silver-catalyzed cascade reaction of β-enaminones and isocyanoacetates affording functionalized pyrrole derivatives is reported. In this reaction, tautomeric equilibria of β-enaminones are utilized to generate imine partners in situ. A hypothesized sequential Mannich addition/cyclization of imine tautomers and isocyanoacetates followed by an unprecedented ring-opening of the resultant 2-imidazolines and dehydration-condensation deliver the final 1,2,4,5-tetrasubstituted pyrrole products.

Three dimeric sesquiterpenoids (1-3), fortunoid A (1) possessing a new carbon skeleton of rearranged lindenane dimer and fortunoids B (2) and C (3) representing the first example of the dimers of a lindenane and a eudesmane sesquiterpene, were isolated from Chloranthus fortunei. Their structures with absolute configurations were established by spectroscopic data and electric circular dichroism analysis. Their biosynthetic origins were also proposed. Compounds 1 and 2 showed moderate antimalarial activities.

Three new ring B-seco limonoids, ciliatonoids A-C (1-3), were isolated from Toona ciliate and structurally characterized by spectroscopic data, X-ray crystallography, and electronic circular dichroism analysis. Ciliatonoids A and B feature an unprecedented limonoid architecture, while ciliatonoid C belongs to a rare class of limonoids. Biological evaluation showed that compound 3 exhibited modest activities against the tested tumor cell lines.

Four limonoids, cipacinoids A-D (1-4), with spirocyclic skeletons were isolated from Cipadessa cinerascens. It is particularly notable that compounds 1-3 had a 17S-configuration for the first time in the limonoid family. Their structures with absolute configurations were assigned by spectroscopic data, X-ray crystallography, and CD analysis. Compound 1 showed moderate protein tyrosine phosphatase 1B (PTP1B) inhibition.

Push-pull alkenes, which bear electron-donating and -accepting group(s) at both termini of a C═C double bond, respectively, are of interest not only for their unique electronic properties but also for their importance as versatile building blocks in organic synthesis. In the world of ketene acetals having the push-pull alkene skeleton, ketene N,S-acetal is most likely the biggest family according to the number and types of these compounds. The first ketene N,S-acetal compound was reported in 1956. As a cyclic ketene N,S-acetal compound, nithiazine, the first lead structure of neonicotinoid insecticides, was reported in 1978. The characteristics of ketene N,S-acetals, which have the structural feature of ketene S,S-acetals and enaminones, make them versatile and easy to use, especially in cyclization and multicomponent reactions for the synthesis of various heterocyclic systems and related natural products. There has been an increasing wealth of information about the synthesis and synthetic applications of ketene N,S-acetals, especially, in recent years. This review provides comprehensive knowledge on the chemistry of ketene N,S-acetals.