Tackling application limitations of high-safetyγ-butyrolactone electrolytes:Exploring mechanisms and proposing solutions

Developing wide-temperature and high-safety lithium-ion batteries(LIBs)presents significant challenges attributed to the absence of suitable solvents possessing broad liquid range and non-flammability properties.γ-Butyrolactone(GBL)has emerged as a promising solvent;however,its incompatibility with graphite anode has hindered its application.This limitation necessitates a comprehensive investigation into the underlying mechanisms and potential solutions.In this study,we achieve a molecular-level understanding of the perplexing interphase formation process by employing in-situ spectroelectrochemical techniques and density function calculations.Our findings reveal that,even at high salt concentrations,GBL consistently occupies the primary Li^(+)solvation sheath,leading to extensive GBL decomposition and the formation of a high-impedance and inorganic-poor solid-electrolyte interphase(SEI)layer.Contrary to manipulating solvation structures,our research demonstrates that the utilization of filmforming additives with higher reduction potential facilitates the pre-establishment of a robust SEI film on the graphite anode.This approach effectively inhibits GBL decomposition and significantly enhances the battery's lifespan.This study provides the first reported intrinsic understanding of the unique GBLgraphite incompatibility and offers valuable insights for the development of wide-temperature and high-safety LIBs.

Asymmetric Synthesis of α-Substituted-γ-butyrolactone Empolying Prolinol Type of Auxiliaries

Eleven (S)-(-)-bishydrocarbyl-(1-alkanoylpyrrolidin-2-yl)-methanol derivatives of three types were synthesized from L-proline, asymmtrically selective alkylation products were obtained by LDA treatment and alkylation using methyl 2-bromoethyl ether, and three types of chiral α-substituted-γ-butyrolactones were obtained by hydrolyzing the alkylation products, with %e.e. being up to 89 percent.

The stable planar conformation of the γ-butyrolactone ring in solution

The conformations ofγ-butyrolactone ring in solution were deduced on the basis of ~1H NMR spectra of geminal protons of the butyrolactone ring.A series of optically pure(Z)-(-)-4-(1 -alkoxyl-1 -carbalkoxy-methylene)-5(R)[(1R)-menthyloxy]-γ-butyr-olactones with a stable planar conformation of γ-butyrolactone ring were found.

Promotional Effect of CoO(OH) on Selective Hydrogenation of Maleic Anhydride to γ-Butyrolactone over Supported Ruthenium Catalyst

A decorated ruthenium catalyst was prepared by the coprecipitation method and used for the selective hydrogenation of maleic anhydride(MA) to γ-butyrolactone(GBL). The as-prepared catalyst was characterized by XRD, TGDTG and N2 adsorption techniques. The characterization tests revealed that the catalyst carrier was composed of monoclinic zirconia(m-ZrO2) and hydroxyl cobalt oxide(CoO(OH)). The hydrogenation results showed that the content of CoO(OH), the reaction temperature, the hydrogen pressure and the reaction time significantly affected the catalytic selectivity to GBL. The promotional effect of CoO(OH) was remarkable, which led to an obvious increase in GBL selectivity. An 100% MA conversion and 92.0% selectivity to GBL were achieved over the Ru/ZrO2-CoO(OH)(35%) catalyst in water solvent under the conditions involving a reaction temperature of 180 ℃, a hydrogen pressure of 3.0 MPa, and a reaction time of 6 h.

Highly Branched Poly(α-Methylene-γ-Butyrolactone) from Ring-Opening Homopolymerization

New heteroleptic lanthanide complex [L1ILaN{Si(CH3)2}] (1) containing tridentate [ONO] ancillary ligand was synthesized from an acid-base ligand exchange reaction with ligands H2L1 and corresponding homoleptic lanthanide compound La[N{Si(CH3)3}2]3. Meanwhile, dimeric complexes [L1LaCl] (2) and [L1ILaCl] (3) were prepared from salt metathesis reaction between one equivalent of ligands H2LI,II, three equivalent of NaN{Si(CH3)3}2, and one equivalent of LaCl3. These compounds were characterized by nuclear magnetic resonance (300 MHz) and elemental analysis. These complexes were used as catalysts in the ring-opening homopolymerization of α-methylene-γ-butyrolactone. While compound 1 did not show any significant reactivity, compounds 2 and 3 gave significant amount of highly branched poly(α-methylene-γ-butyrolactone) as confirmed by 1H NMR spectroscopy and Malvern’s triple detector GPCMax analysis in DMSO with molecular weights of over 500,000 Dalton. The glass-transition temperatures of the branched polymer samples were determined using a Dynamic Mechanical Analyzer, DMA Q800.

An Efficient Method for α-Alkylation of γ-Butyrolactone

This paper provides a simple, convenient and mild condition method for -alkylation of g-butyrolactone. Three types of (E)-a-alkenyl-g-butyrolactone compounds were synthesized by condensation of corresponding aldehydes and g-butyrolactone, using MeONa and EtONa as base. Then the a-alkyl-g-butyrolactones were gained by reducing the former alkenyl compounds through catalytic transfer hydrogenation under Pd/C catalyst with sodium hypophosphite at room temperature.

Continuous-flow synthesis of polysubstituted γ-butyrolactones via enzymatic cascade catalysis

Polysubstituted chiral γ-butyrolactones are the core structural units of many natural products and high value-added flavors and fragrances used in the food and cosmetic industry. Current enzymatic cascade synthesis of these molecules faces the problems of low enzyme activity and phase separation in batch reaction, resulting in low productivity. Herein, we report a new continuous-flow process to synthesize the optically pure Nicotiana tabacum lactone(3S,4S)-4a and whisky lactone(3R,4S)-4b from α,β-unsaturatedγ-ketoesters. A new ene reductase(ER) from Swingsia samuiensi(Ss ER) and a carbonyl reductase(Ss CR)were engineered by directed evolution to improve their activity and thermostability. The continuous-flow preparative reactions were performed in two 3D microfluidic reactors, generating(3S,4S)-4a(99% ee and87% de) and(3R,4S)-4b(99% ee and 98% de) with space-time yields 3 and 7.4 times higher than those of the batch reactions. The significant enhancement in the productivity of enzyme cascade catalysis brought by cutting-edge continuous microfluidic technology will benefit the general multi-enzyme catalytic systems in the future.

Stereodivergent synthesis ofα-fluoroα-azaarylγ-butyrolactones via cooperative copper and iridium catalysis

The development of stereodivergent synthetic methods to access all four stereoisomers of biologically importantα-fluoroγ-butyrolactones containing vicinal stereocenters is of great importance and poses a formidable challenge owing to ring strain and steric hindrance.Herein,a novel asymmetric[3+2]annulation ofα-fluoroα-azaaryl acetates with vinylethylene carbonate was successfully developed through Cu/Ir-catalyzed cascade allylic alkylation/lactonization,affording a variety of enantioenrichedα-fluoroγ-butyrolactones bearing vicinal stereogenic centers with high reaction efficiency and excellent levels of both stereoselectivity and regioselectivity(up to 98%yield,generally>20:1 dr and>99%ee).Notably,all four stereoisomers of these pharmaceutically valuable molecules could be accessed individually via simple permutations of two enantiomeric catalysts.In addition,other azaaryl acetates bearingα-methyl,α-chlorine orα-phenyl group were tolerated well in this transformation.Reaction mechanistic investigations were conducted to explore the process of this bimetallic catalysis based on the results of reaction intermediates,isotopic labelling experiments,and kinetic studies.

A widespread response of Gram-negative bacterial acyl-homoserine lactone receptors to Gram-positive Streptomyces γ-butyrolactone signaling molecules

Cell-cell communication is critical for bacterial survival in natural habitats,in which miscellaneous regulatory networks are encompassed.However,elucidating the interaction networks of a microbial community has been hindered by the population complexity.This study reveals thatγ-butyrolactone(GBL)molecules from Streptomyces species,the major antibiotic producers,can directly bind to the acyl-homoserine lactone(AHL)receptor of Chromobacterium violaceum and influence violacein production controlled by the quorum sensing(QS)system.Subsequently,the widespread responses of more Gram-negative bacterial AHL receptors to Gram-positive Streptomyces signaling molecules are unveiled.Based on the cross-talk between GBL and AHL signaling systems,combinatorial regulatory circuits(CRC)are designed and proved to be workable in Escherichia coli(E.coli).It is significant that the QS systems of Gram-positive and Gram-negative bacteria can be bridged via native Streptomyces signaling molecules.These findings pave a new path for unlocking the comprehensive cell-cell communications in microbial communities and facilitate the exploitation of innovative regulatory elements for synthetic biology.

A new γ-alkylated-γ-butyrolactone from the roots of Solanum melongena

A new γ-alkylated-γ-butyrolactone, named melongenolide A(1), along with nine known compounds were obtained from the roots of Solanum melongena, and their structures were identified as melongenolide A(1),(+)-syringaresinol(2),(+)- lyoniresinol(3), 5,5′-dimethoxy lariciresinol(4),(+)-(7R,8R)-4-hydroxy-3,3′,5′-trimethoxy-8′,9′-dinor-8,4′-oxyneoligna-7, 9-diol-7′- aldehyde(5), kaempferol-3-O-(2′′,6′′-di-O-p-trans-coumaroyl)-β-glucoside(6), arjunolic acid(7), vanillic acid(8), scoparone(9), and β-sitosterol(10). Compounds 2, 6, and 7 showed potent inhibitory effects on nitric oxide production in lipopolysaccharide-induced RAW 264.7 macrophages, with IC50 values being 5.62 ± 0.86, 11.47 ± 0.98, and 27.75 ± 1.26 μmol·L-1, respectively.

Fully Chemical Recyclable Poly(γ-butyrolactone)-based Copolymers with Tunable Structures and Properties

The emerging chemical recyclable polymers,such as poly(γ-butyrolactone)(PGBL)and poly((R)-3,4-trans six-membered ring-fused GBL)(P((R)-M)),provide a good solution to the plastic pollution.However,these homopolymers suffer from limited structures and properties.Herein,we reported a fully chemical recyclable copolymer P(GBL-co-((R)-M))through ring-opening copolymerization(ROCOP)of GBL and(R)-M.By employing organomagnesium as the catalyst and regulating the reaction conditions,the chemical structures of copolymers were wellcontrolled(GBL content=13%-78%,Mn=6560-15600 g/mol,DM=1.08-1.59).The resultant P(GBL-co-((R)-M))exhibited fully chemical recyclability,which rapidly and quantitatively depolymerized into initial GBL and(R)-M monomer through chemolysis.By varying GBL content,tunable thermal properties were achieved for P(GBL-co-((R)-M)).The onset decomposition temperatures of copolymers varied from 193°C to 234°C.A linear evolution of glass transition temperature(T_(g))of P(GBL-co-((R)-M))versus GBL content was obtained as following equation of Tg=-1.06×GBL mol%×100+39.6.We hope that the reported fully chemical recyclable copolymers with tunable structures and properties would serve as the candidate material for sustainable applications.

IONIC CONDUCTIVITY OF POLY (β-ALKOXYCARBONYLETHYLMETHYLSILOXANE)-LiClO_4 CROSSLINKED FILMS

Poly (β-carboxyethylmethylsiloxane)-LiClO_4 and poly (β-alkoxylethylmethylsiloxane)-LiClO_4 crosslinked fllms have been prepared. The ionic conductivity of the films depends on the polymer species, concentration of lithium perchlorate, temperature and content of crosslinking agent. The effect of high polar organic solvent 1, 4-butyrolactone on the ionic conductivity and mechanical properties of poly (β-carhoxyethylmethylsiloxane )-LiClO_4 system was also investignied.

Samarium diiodide induced asymmetric synthesis of γ-butyrolactone using chiral auxiliaries derived from isosorbide and isomannide

The asymmetric reductive coupling reaction of various acrylates derived from D-isosorbide and D-isomannide with acetophenone mediated by samarium diiodide to give both enantiomers of the optically active γ-butyrolactone was described. The best enantiomeric excess of the products was 60%.

Costunolide covalently targets NACHT domain of NLRP3 to inhibit inflammasome activation and alleviate NLRP3-driven inflammatory diseases

The NLRP3 inflammasome’s core and most specific protein,NLRP3,has a variety of functions in inflammation-driven diseases.Costunolide(COS)is the major active ingredient of the traditional Chinese medicinal herb Saussurea lappa and has anti-inflammatory activity,but the principal mechanism and molecular target of COS remain unclear.Here,we show that COS covalently binds to cysteine 598 in NACHT domain of NLRP3,altering the ATPase activity and assembly of NLRP3 inflammasome.We declare COS’s great anti-inflammasome efficacy in macrophages and disease models of gouty arthritis and ulcerative colitis via inhibiting NLRP3 inflammasome activation.We also reveal that theα-methylene-γ-butyrolactone motif in sesquiterpene lactone is the certain active group in inhibiting NLRP3 activation.Taken together,NLRP3 is identified as a direct target of COS for its anti-inflammasome activity.COS,especially theα-methylene-γ-butyrolactone motif in COS structure,might be used to design and produce novel NLRP3 inhibitors as a lead compound.

Organocatalytic enantioselective construction of bicyclic γ-butrolactones

An enantioselective organo-catalyzed reaction of furanones with α,β-unsaturated ketones has been established herein, which provides an efficient access to chiral bicyclic γ-butyrolactones in good yields, enantioselectivities and diastereoselectivities. Further transformations of product are demonstrated. A diamine mediated catalytic cycle is proposed.

Neomycin biosynthesis is regulated positively by AfsA-g and NeoR in Streptomyces fradiae CGMCC 4.7387

Neomycins are a group of aminoglycoside antibiotics with both clinical and agricultural applications.To elucidate the regulatory mechanism of neomycin biosynthesis,we completed draft genome sequencing of a neomycin producer Streptomyces fradiae CGMCC 4.7387 from marine sediments,and the neomycin biosynthesis gene cluster was identified.Inactivation of the afsA-g gene encoding a γ-butyrolactone(GBL) synthase in S.fradiae CGMCC 4.7387 resulted in a significant decrease of neomycin production.Quantitative RT-PCR analysis revealed that the transcriptional level of neoR and the aphA-neoGH operon were reduced in the afsA-g::aac(3)Ⅳ mutant.Interestingly,a conserved binding site of AdpA,a key activator in the GBL regulatory cascade,was discovered upstream of neoR,a putative regulatory gene encoding a protein with an ATPase domain and a tetratricopeptide repeat domain.When neoR was inactivated,the neomycin production was reduced about 40%in comparison with the WT strain.Quantitative RT-PCR analysis revealed that the transcriptional levels of genes in the aphA-neoGH operon were reduced clearly in the neoR::aac(3)Ⅳ mutant.Finally,the titers of neomycin were improved considerably by overexpression of qfsA-gand neoR in S.fradiae CGMCC 4.7387.

Tautomerizations and intramolecular hydrogen bondings of the chiral α-nitroester, α-nitrosoester and α-ketoester

Interesting and diverse tautomerizations and intramolecular hydrogen bondings of the chiral α-nitroester, α-nitrosoester and α-ketoester are described and rationally interpreted.

Synthesis of Optically Active β-Alkyl-α-methylene-γ-butyro- lactones from Enantioselective Biotransformation of Nitriles, an Unusual Inversion of Enantioselectivity

A new approach to optically active β-alkyl-α-methylene-γ-butyrolactone derivatives was reported from the Rhodococcus sp. AJ270-catalyzed hydrolysis of appropriate nitriles. The inversion of enantioselectivity of the amidase has been observed when a methyl protection was introduced into the hydroxy group of the parent substrate.