Electro-oxidative intermolecular CSP2-H amination of heteroarenes via proton-coupled electron transfer.

A new electrochemical proton-coupled electron transfer method for the intermolecular CSP2-H amination of heteroarenes without oxidants, metal catalysts and external electrolytes has been developed. Various new N-containing heteroarenes were prepared in medium to high yields, and the indole-containing product could be converted into practical 2-oxindole by simple basic hydrolysis. Mechanistic investigation indicated that ester sulfonyl-substituted N-radicals could be formed by the combination of 2,6-lutidine and electrochemical oxidation, which is the key to achieve the desired chemoselectivity.

Pseudohalioglobus sediminis sp. nov., isolated from coastal sediment.

A Gram-stain-negative, strictly aerobic, non-motile and rod-shaped bacterial strain, designated NY5T, was isolated from marine sediment collected from coastal area in Weihai, China (122°07' 38.80'' E, 37°33' 57.60'' N). Cells of strain NY5T were 0.6-0.7 µm width and 1.9-2.0 µm length, catalase-positive and oxidase-positive. Growth of NY5T was observed at 25-37 °C (optimum, 28 °C) and pH 6.5-9.5 (optimum, pH 7.5-8.0) and in the presence of 0.5-7.0% (w/v) NaCl (optimum, 2.0%). The isoprenoid quinone was Q-8 and the predominant fatty acids were summed feature 8 (C18:1 ω7c and/or C18:1 ω6c), summed feature 3 (C16:1 ω7c and/or C16:1 ω6c) and C17:1 ω8c. Diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol were the major polar lipids. The DNA G+C content of strain NY5T was 60.1%. Strain NY5T showed the highest 16S rRNA gene sequence similarity (98.2%) with Pseudohalioglobus lutimaris followed by Parahaliea aestuarii (96.9%), Parahaliea maris (96.7%), Parahaliea mediterranea (95.9%), and Halioglobus japonicus (94.9%). Given these phenotypic and chemotaxonomic properties and phylogenetic analyses, strain NY5T was considered to represent a novel species of the genus Pseudohalioglobus, for which the name Pseudohalioglobus sediminis sp. nov. is proposed. The type strain is NY5T (=KCTC 72416T=MCCC 1H00401T).

Nitrative bicyclization of 1,7-diynes for accessing skeletally diverse tricyclic pyrroles.

A novel metal-free nitrative bicyclization of 1,7-diynes with tBuONO in the presence of H2O is reported, producing three types of skeletally diverse tricyclic pyrroles, namely pyrrolo[3,4-c]quinolines, chromeno[3,4-c]pyrroles and benzo[e]isoindoles, with moderate to good yields by simply tuning the linkers of the 1,7-diynes. This domino protocol demonstrates remarkable compatibility regarding 1,7-diynes with different linkers, such as nitrogen and oxygen atoms and a hydroxymethyl group, and tBuONO plays dual roles as a nitro precursor as well as a nitrogen atom source.

Diastereoselective Generation of C2-Azlactonized 2H-Chromenes via Brønsted Acid-Catalyzed Oxo-Cyclization of Propargyl Alcohols.

A new Brønsted acid-catalyzed oxo-cyclization of propargyl alcohols with azlactones to synthesize C2-azlactonized 2H-chromenes has been established that uses 1,1'-binaphthyl-2,2'-diyl hydrogen phosphate (BiNPO4H) as the catalyst and gives excellent diastereoselectivities (≥19:1 dr) in most cases. This protocol has a high compatibility with various substituents of substrates, offering a catalytic and useful entry to the fabrication of the synthetically important C2-functionalized 2H-chromene scaffold.

Cyclic Oxime Esters as Deconstructive Bifunctional Reagents for Cyanoalkyl Esterification of 1,6-Enynes.

A concise copper catalysis strategy for the addition-cyclization of cyclic oxime esters across 1,6-enynes with high stereoselectivity to generate 1-indanones bearing an all-carbon quaternary center is reported. In this process, single-electron reduction of cyclic oxime esters enables deconstructive carbon-carbon cleavage to provide a key cyanopropyl radical poised for the addition-cyclization. This reaction is redox-neutral, exhibits good functional group compatibility, and features 100% atomic utilization. This process driven by copper catalyst makes readily available cyclic oxime esters as bifunctional reagents to demonstrate convergent synthesis.

Photocatalytic Biheterocyclization of 1,7-Diynes for Accessing Skeletally Diverse Tricyclic 2-Pyranones.

A new and green route to skeletally diverse oxo-heterocyclic architectures such as pyrano[3,4-c]chromen-2-ones and pyrano[3,4-c]quinolin-2-ones is reported via an unprecedented photocatalytic Kharasch-type cyclization/1,5-(SN″)-substitution/elimination/6π-electrocyclization/double nucleophilic substitution cascade starting from easily available heteroatom-linked 1,7-diynes and low-cost CBrCl3. During this reaction process, the full scission of carbon-halogen bonds of BrCCl3 was realized to directly build two new rings, including a lactone scaffold, using H2O as the oxygen source of the ester group.

Salibaculum halophilum gen. nov., sp. nov. and Salibaculum griseiflavum sp. nov., in the family Rhodobacteraceae.

Two Gram-stain-negative, moderately halophilic, non-motile, rod-shaped, pale yellow, and aerobic strains, designated WDS1C4T and WDS4C29T, were isolated from a marine solar saltern in Weihai, Shandong Province, PR China. Growth of strain WDS1C4T occurred at 10-45 °C (optimum, 37 °C), with 4-16 % (w/v) NaCl (optimum, 8 %) and at pH 6.5-9.0 (optimum, pH 7.5). Growth of strain WDS4C29T occurred at 10-45 °C (optimum, 40 °C), with 2-18 % (w/v) NaCl (optimum, 6 %) and at pH 6.5-9.0 (optimum, pH 7.5). Q-10 was the sole respiratory quinone of the two strains. The major polar lipids of strains WDS1C4T and WDS4C29T were phosphatidylglycerol, phosphatidylethanolamine and phosphatidylcholine. The major cellular fatty acid in strains WDS1C4T and WDS4C29T was C18 : 1 ω7c, and the genomic DNA G+C contents of strains WDS1C4T and WDS4C29T were 67.6 and 63.3 mol%, respectively. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strains WDS1C4T and WDS4C29T were members of the family Rhodobacteraceae and showed 94.3 and 95.3 % similarities to their closest relative, Celeribacter indicus, respectively. The similarity between WDS1C4T and WDS4C29T was 97.3 %. Differential phenotypic and genotypic characteristics of the two isolates from recognized genera showed that the two strains should be classified as representing two novel species in a new genus for which the names Salibaculum halophilum gen. nov., sp. nov. (type species, type strain WDS1C4T=MCCC 1H00179T=KCTC 52542T) and Salibaculum griseiflavum sp. nov. (WDS4C29T=MCCC 1H00175T=KCTC 52541T) are proposed.

Mitochondria autophagy: a potential target for cancer therapy.

Mitophagy is a selective form of macroautophagy in which dysfunctional and damaged mitochondria can be efficiently degraded, removed and recycled through autophagy. Selective removal of damaged or fragmented mitochondria is critical to the functional integrity of the entire mitochondrial network and cells. In past decades, numerous studies have shown that mitophagy is involved in various diseases; however, since the dual role of mitophagy in tumour development, mitophagy role in tumour is controversial, and further elucidation is needed. That is, although mitophagy has been demonstrated to contribute to carcinogenesis, cell migration, ferroptosis inhibition, cancer stemness maintenance, tumour immune escape, drug resistance, etc. during cancer progression, many research also shows that to promote cancer cell death, mitophagy can be induced physiologically or pharmacologically to maintain normal cellular metabolism and prevent cell stress responses and genome damage by diminishing mitochondrial damage, thus suppressing tumour development accompanying these changes. Signalling pathway-specific molecular mechanisms are currently of great biological significance in the identification of potential therapeutic targets. Here, we review recent progress of molecular pathways mediating mitophagy including both canonical pathways (Parkin/PINK1- and FUNDC1-mediated mitophagy) and noncanonical pathways (FKBP8-, Nrf2-, and DRP1-mediated mitophagy); and the regulation of these pathways, and abovementioned pro-cancer and pro-death roles of mitophagy. Finally, we summarise the role of mitophagy in cancer therapy. Mitophagy can potentially be acted as the target for cancer therapy by promotion or inhibition.

Copper-Catalyzed Annulation-Cyanotrifluoromethylation of 1,6-Enynes Toward 1-Indanones via a Radical Process.

A new Cu(II)-catalyzed annulation-cyanotrifluoromethylation of 1,6-enynes with Togni's reagent and trimethylsilyl cyanide (TMSCN) has been established, enabling the direct construction of trifluoromethylated 1-indanones with an all-carbon quaternary center in good yields. This reaction was performed by using low-cost Cu(OTf)2 as the catalyst and Togni's reagent as both the radical initiator and a CF3 source, providing an efficient protocol for building up an 1-indanone framework with wide functional group compatibility. The reaction mechanism was proposed through a radical triggered addition/5-exo-dig cyclization/oxidation/nucleophilic cascade.

Silver-Catalyzed Nitration/Annulation of α-Alkynyl Arylols toward 3-Nitrated Benzofurans.

A silver-catalyzed nitration/annulation of α-alkynyl arylols is reported by using tert-butyl nitrite (TBN) as a NO2 radical precursor, from which a set of 3-nitrated benzofurans were synthesized with moderate to good yields. This transformation initiated by an in situ generated NO2 radical proceeds efficiently under mild and neutral redox conditions, which provides a new pathway toward the 3-nitrobenzofuran framework via catalytic difunctionalization of internal alkynes.

tert-Butyl peroxide (TBHP)/KI-mediated dual C(sp2)-H bond amination of arylamines with α-diazo carbonyls toward 1,2,4-benzotriazines.

A new radical-induced dehydrogenative heterocyclization of arylamines with α-diazo carbonyls has been established under metal-free oxidative conditions, enabling two-fold C(sp2)-H bond amination to access a wide range of functionalized 1,2,4-triazine derivatives with generally good yields by combining KI/tert-butyl peroxide (TBHP). The present protocol features wide substrate scope, commercial accessibility, and mild reaction conditions. Mechanistic details of this radical process are rendered by conducting systematic theoretical calculations.

Cu-Catalyzed [4+1] Annulation toward Indolo[2,1-a]isoquinolines through Oxidative C(sp3 )/C(sp2 )-H Bond Bifunctionalization.

A Cu-catalyzed [4+1] annulation of N-aryl-1,2,3,4-tetrahydroisoquinolines (N-aryl THIQs) with α-diazoketones has been established under oxidative conditions, leading to the construction of a series of indolo[2,1-a]isoquinolines with generally good yields. The reaction enables dediazotized dicarbonylation of α-diazoketones, creating direct C(sp3 )/C(sp2 )-H bond bifunctionalization to access tetracyclic aza-heterocyclic skeletons.

Substrate-Controlled Generation of 3-Sulfonylated 1-Indenones and 3-Arylated ( Z)-Indenes via Cu-Catalyzed Radical Cyclization Cascades of o-Alkynylbenzonitriles.

Substrate-controlled generation of 3-sulfonylated 1-indenones and 3-arylated ( Z)-indenes through radical cyclization cascades of o-alkynylbenzonitriles with sulfonyl hydrazides was established by combining copper(II) with tert-butyl hydroperoxide (TBHP) as a catalytic oxidative system. With the installation of the aryl group (R1) into the alkynyl unit, sulfonyl radicals triggered addition-cyclization cascades to access 3-sulfonylated 1-indenones with good yields by using a Cu/TBHP system, whereas a series of new functionalized 3-arylated ( Z)-indenes were obtained in good yields when o-alkynylbenzonitriles bearing the alkyl group in the alkynyl unit were subjected with arylsulfonyl hydrazides with an electron-rich nature under the above conditions.

Sulfinate-Salt-Mediated Radical Relay Cyclization of Cyclic Ethers with 2-Alkynylbenzonitriles toward 3-Alkylated 1-Indenones.

A new sulfinate salt-mediated radical relay for the completion of C(sp3 )-H bond indenylation of cyclic ethers with readily available 2-alkynylbenzonitriles by combining silver/tert-butyl peroxide (TBHP) was established, providing a wide range of 3-alkylated 1-indenones with generally good yields. Interestingly, the current reaction system can tolerate an S-centered radical and a C-centered radical in one pot, in which the S-centered radical promotes the formation of the C-centered radical to induce a radical cascade without disturbing the reaction process. A reaction mechanism is also proposed based on control experiments.

Thiazolium salt-catalyzed C-C triple bond cleavage for accessing substituted 1-naphthols via benzannulation.

The first thiazolium salt-catalyzed C-C triple bond cleavage of benzene-linked allene-ynes has been established. The reaction pathway involves [2+2] cycloaddition and ring-opening of in situ generated cyclobutenes with H2O under mild and convenient conditions, and provides practical access to substituted 1-naphthols with potentially valuable applications.

DDQ-Mediated Three-Component Dioxygenation of Alkenes.

A new DDQ-mediated three-component dioxygenation of alkenes has been established, providing a direct and metal-free access toward densely functionalized 4,5-dichloro-3-hydroxyphthalonitrile derivatives with generally good to excellent yields under mild conditions. During this process, DDQ plays dual roles as both a dehydrogenation reagent and a coupling partner, enabling oxidative coupling to form two C-O functionalities in a highly atom-economy fashion.

Catalytic Oxidative Carbene Coupling of α-Diazo Carbonyls for the Synthesis of ß-Amino Ketones via C(sp(3))-H Functionalization.

A catalytic domino oxidative carbene coupling (OCC) of α-diazo carbonyls has been established by treatment with N,N-dimethylanilines and carboxylic acids (or N-methylaniline) via direct C(sp(3))-H functionalization under convenient conditions. The reaction pathway is proposed to proceed through the sequence of carbene formation, enolization, and nucleophilic addition. The reaction enables de-diazotized carbo-oxygenation and carbo-amination of α-diazo carbonyls and provides practical access to α-(acyloxy)-ß-amino ketones and α,ß-diamino ketones.

Metal-free C(sp(3))-H functionalization: oxidative carbo-oxygenation of α-diazo carbonyls via radical dediazotization.

A novel three-component carbo-oxygenation of α-diazo carbonyls for flexible synthesis of unprecedented α-aminooxy-ß-amino ketones has been established through metal-free C(sp(3))-H functionalization from readily accessible N,N-dimethylanilines and N-hydroxyphthalimide. The reaction pathway involves an in situ-generated phthalimide N-oxyl radical-triggered dediazotization/radical coupling sequence, leading to C-O and C-C bond formation.

Synergistic Rhodium/Copper Catalysis: Synthesis of 1,3-Enynes and N-Aryl Enaminones.

Synergistic rhodium/copper catalysis enables new three-component coupling reactions of terminal alkynes and α-diazoketones and/or arylamines, allowing dediazotized carbene C-H insertion for the synthesis of functionalized 1,3-enynes and N-aryl enaminones with high stereoselectivity. The synthetic utility of these transformations results in subsequent C-C or/and C-N bond-forming reactions to effectively build up functional molecules with potential significance.

[Two Data Inversion Algorithms of Aerosol Horizontal Distributiol Detected by MPL and Error Analysis].

Atmospheric aerosols have important impacts on human health, the environment and the climate system. Micro Pulse Lidar (MPL) is a new effective tool for detecting atmosphere aerosol horizontal distribution. And the extinction coefficient inversion and error analysis are important aspects of data processing. In order to detect the horizontal distribution of atmospheric aerosol near the ground, slope and Fernald algorithms were both used to invert horizontal MPL data and then the results were compared. The error analysis showed that the error of the slope algorithm and Fernald algorithm were mainly from theoretical model and some assumptions respectively. Though there still some problems exist in those two horizontal extinction coefficient inversions, they can present the spatial and temporal distribution of aerosol particles accurately, and the correlations with the forward-scattering visibility sensor are both high with the value of 95%. Furthermore relatively speaking, Fernald algorithm is more suitable for the inversion of horizontal extinction coefficient.