Based on the parent tetrazole 2N-oxide, six series of novel carbon-linked ditetrazole 2N- oxides with different energetic substituent groups （-NH2, -Na, -NO2, NF2, -NHNO2） and energetic bridge groups （-CH2-, -CH2-C...Based on the parent tetrazole 2N-oxide, six series of novel carbon-linked ditetrazole 2N- oxides with different energetic substituent groups （-NH2, -Na, -NO2, NF2, -NHNO2） and energetic bridge groups （-CH2-, -CH2-CH2-, -NH-, -N=N-, -NH-NH-） were designed. The overall performance and the effects of different energetic substituent groups and energetic bridge groups on the performance were investigated by density functional theory and electrostatic potential methods. The results showed that most of designed compounds have oxygen balance around zero, high heats of formation, high density, high energy, and acceptable sensitivity, indicating that tetrazole N-oxide is a useful parent energetic compound employed for obtaining high energy compounds, even only combined with some very common energetic substituent groups and bridge groups. Comprehensively considering the effects on energy and sensitivity, the -NO2, -NF2, -NH- and-NH-NH- are appropriate substituent groups for combining tetrozale N-oxide to design new energetic compounds, while -NH2, -Na, -CH2-CH2-, and -N=N- are inappropriate.展开更多
An eco-friendly protocol for the synthesis of various 2-sulfonyl quinolines/pyridines through sulfonylation of heteroaromatic N-oxides with sodium sulfinates in water at ambient temperature under metal-and oxidant-fre...An eco-friendly protocol for the synthesis of various 2-sulfonyl quinolines/pyridines through sulfonylation of heteroaromatic N-oxides with sodium sulfinates in water at ambient temperature under metal-and oxidant-free conditions has been developed.The mild reaction conditions,high reaction efficiency,operational simplicity,short reaction time and remarkable functional-group compatibility make the developed protocol very attractive for the preparation of 2-sulfonyl N-heteroaromatic compounds.展开更多
We report a practical and highly efficient protocol for the arylation of pyridine N-oxides with arylboronic acid through palladium-catalyzed Suzuki reaction in water.This ligand-free Suzuki reaction is performed in th...We report a practical and highly efficient protocol for the arylation of pyridine N-oxides with arylboronic acid through palladium-catalyzed Suzuki reaction in water.This ligand-free Suzuki reaction is performed in the presence of diisopropylamine and gives 2-or 3-arylated pyridyl N-oxide derivatives in good to excellent yields within 1 h.展开更多
A new preparation method of the N-ethyl 7,17-seco C_(19)-diterpenoid alkaloids(5)and(6)by pyrolysis of the N-oxides(3)and(4),respectively, in anhydrous diglyme is described.A probable reaction mechanism for the pyroly...A new preparation method of the N-ethyl 7,17-seco C_(19)-diterpenoid alkaloids(5)and(6)by pyrolysis of the N-oxides(3)and(4),respectively, in anhydrous diglyme is described.A probable reaction mechanism for the pyroly- sis is presented and studied preliminarily.展开更多
A highly enantioselective Michael addition of nitro esters to 2-enoyl-pyridine N-oxides was developed by using chiral copper catalysts. The Michael addition products can be obtained in high yields and with up to 96% e...A highly enantioselective Michael addition of nitro esters to 2-enoyl-pyridine N-oxides was developed by using chiral copper catalysts. The Michael addition products can be obtained in high yields and with up to 96% ee. Moreover, asymmetric Michael addition product of nitromethane to 2-enoyl-pyridine N-oxides can be obtained in one step. An analogue of nicotine, dihydro-2H-pyrrol 4b was synthesized with this developed method.展开更多
A simple and efficient method for the synthesis of 2-sulfonylquinoline from deoxygenative C2-sulfonylation of quinoline N-oxides with sulfinic acid induced by visible light is presented.This protocol shows a broad sub...A simple and efficient method for the synthesis of 2-sulfonylquinoline from deoxygenative C2-sulfonylation of quinoline N-oxides with sulfinic acid induced by visible light is presented.This protocol shows a broad substrate scope,and desired products with various substituents can be formed in moderate to high yields at room temperature.展开更多
Herein,we report the first Rh~Ⅲ-catalyzed regioselective C8 arylation of quinoline N-oxides with commercially available arylboronic acids as coupling partners.This procedure is simple,and the reaction shows perfect r...Herein,we report the first Rh~Ⅲ-catalyzed regioselective C8 arylation of quinoline N-oxides with commercially available arylboronic acids as coupling partners.This procedure is simple,and the reaction shows perfect regioselectivity,a broad substrate scope,and isolated yields of up to 92%.We demonstrate the utility of the reaction by using it for late-stage functionalization of a fungicide.展开更多
New solid complexes of europium, uranyl and zinc ions with N-oxides of 4-chloro-2,6-dimethylpyridine, quinoline and 4-meth- oxyquinaldinic acid in presence different anions were obtained and characterized by elemental...New solid complexes of europium, uranyl and zinc ions with N-oxides of 4-chloro-2,6-dimethylpyridine, quinoline and 4-meth- oxyquinaldinic acid in presence different anions were obtained and characterized by elemental and TG analyses, IR and luminescence spectra. The compounds are crystalline, hydrated or anhydrous salts with colours typical of metal ions. Thermal studies showed that in hydrated salts lattice or coordination water molecules are present. A role of different anions in the formation of various types of the complexes is presented.展开更多
A KOtBu-mediated C2-benzylation of quinoline N-oxides with benzylboronates under mild reaction conditions has been developed.The reaction shows broad scope for both of the quinoline N-oxides and benzylboronates,especi...A KOtBu-mediated C2-benzylation of quinoline N-oxides with benzylboronates under mild reaction conditions has been developed.The reaction shows broad scope for both of the quinoline N-oxides and benzylboronates,especially,secondary and tertiary benzylboronates are also compatible with this reaction.DFT calculations indicate that the reaction is promoted by the nucleophilic addition of KOtBu to boronate rather than the deprotonation of benzylic C−H bond with KOtBu.展开更多
Aliphatic amine N-oxides, particularly （CH<sub>3</sub>）<sub>3</sub>NO, have been widely used as O-atom transfer reagents in organometallic chemistry. Recently the systematic kinetic studies o...Aliphatic amine N-oxides, particularly （CH<sub>3</sub>）<sub>3</sub>NO, have been widely used as O-atom transfer reagents in organometallic chemistry. Recently the systematic kinetic studies on O-atom transfer reactions have been reported in detail. However, little is known about the use of pyridine N-oxides and the related aromatic amine N-oxides as O-atom transfer reagents in organometallic chemistry, and no kinetic or展开更多
A highly efficient enantioselective construction of heterobiaryl N-oxides was developed.A series of axially chiral heterobiaryl N-oxides were generated via the cascade reaction of aminobenzamides with heterobiaryl ald...A highly efficient enantioselective construction of heterobiaryl N-oxides was developed.A series of axially chiral heterobiaryl N-oxides were generated via the cascade reaction of aminobenzamides with heterobiaryl aldehydes in the presence of chiral phosphoric acids.A number of atropisomers were afforded in moderate to good yields with excellent enantioselectivities and diastereoselectivities.Preliminary results demonstrate that the heterobiaryl N-oxides can be utilized as efficient chiral ligands in asymmetric catalysis.展开更多
Novel phenylene-bridged zinc bisporphyrins （1-4）, fulleropyrrolidines （C60-m, C60-h） and their N-oxides （C60-mo, C60-ho） were synthesized. The fluorescence quenching processes of bisporphyrins in toluene solutio...Novel phenylene-bridged zinc bisporphyrins （1-4）, fulleropyrrolidines （C60-m, C60-h） and their N-oxides （C60-mo, C60-ho） were synthesized. The fluorescence quenching processes of bisporphyrins in toluene solution by fulleropyrrolidines and their N-oxides were investigated by steady-state fluorescence spectra. The fluorescence quenching constants proved that the fluorescence quenching ability was decreased as reduction of the pyrrolidine functional groups of fullerene surface： C60-h〉C60-m〉C60, and the fluorescence quenching ability was increased about 1.3-7.4 times by utilizing fulleropyrrolidine N-oxides （C60-mo, C60-ho） compared to fulleropyrrolidine compounds （C60-m, C60-h）. The results revealed photoinduced electron transfer （PET） efficiency between bispor-phyrin and fullerene derivatives could be tunable by change of functional groups on fullerene surface.展开更多
BACKGROUND Diabetic nephropathy(DN)is one of the most serious microvascular complications of type 2 diabetes mellitus(T2DM),and its incidence increases with the global rise in diabetes prevalence.It is the leading cau...BACKGROUND Diabetic nephropathy(DN)is one of the most serious microvascular complications of type 2 diabetes mellitus(T2DM),and its incidence increases with the global rise in diabetes prevalence.It is the leading cause of chronic kidney disease and end-stage kidney disease.Patients with DN often experience complex metabolic disorders and chronic inflammatory states,which not only accelerate the decline of renal function but are also closely related to complications such as cardiovascular events and osteoporosis(OP),seriously compromising quality of life.With the in-depth research on the gut microbiota and the emergence of concepts such as the"gut-kidney axis"and the"enteric-bone axis",the key roles of the gut microbiota and its metabolites in metabolic disorders,inflammatory responses,and target organ damage have been increasingly recognized.However,the specific role of gut microbiota in the pathogenesis of DN remains to be further explored.The results obtained may provide evidence to better understand the pathogenesis of DN and to identify high-risk populations at an early stage.This research direction is of strategic significance.AIM To assess the correlation of the gut microbiota metabolite trimethylamine N-oxide(TMAO)with inflammatory marker levels and OP in patients with DN.METHODS A total of 115 patients diagnosed with type 2 DN and treated at the Department of Endocrinology,Second Affiliated Hospital of Shandong First Medical University from August 2022 to December 2024 were enrolled in the DN group,and 115 patients with T2DM without nephropathy were included in the T2DM group.The two groups were compared in terms of gastrointestinal microbiota abundance and relative abundance at the genus level;levels of TMAO,inflammatory markers[including C-reactive protein(CRP),interleukin-6(IL-6),interleukin-8(IL-8),and tumor necrosis factor-α(TNF-α)],and bone metabolism markers[including procollagen type I N-terminal propeptide(PINP),β-CrossLaps(β-CTX),and alkaline phosphatase(ALP)];and lumbar spine and hip bone mineral density(BMD).The correlation of TMAO level with inflammatory factor and bone metabolism indicator levels was further analyzed.RESULTS The DN group had higher Chao1 and Simpson indices of gastrointestinal microbiota diversity than the T2DM group,whereas the ACE and Shannon indices were lower(P<0.05).The relative abundance of Firmicutes was higher,and the relative abundances of Bacteroidetes,Proteobacteria,and Actinobacteria were lower in the DN group than in the T2DM group(P<0.05).CRP,IL-6,IL-8,TNF-α,and TMAO levels were considerably elevated in the DN group compared to the T2DM group(P<0.05).Moreover,the DN group had higher levels of bone turnover markers-including PINP,β-CTX,and ALP-but lower lumbar spine and hip BMDs than the T2DM group(P<0.05).TMAO level positively correlated with the Chao1 and Simpson indices and negatively correlated with the ACE and Shannon indices of gut microbiota diversity.TMAO level also negatively correlated with the relative abundances of Bacteroidetes,Proteobacteria,and Actinobacteria and positively correlated with the abundance of Firmicutes.Additionally,TMAO level positively correlated with the inflammatory markers CRP,IL-6,IL-8,and TNF-α,as well as with the bone turnover markers PINP,β-CTX,and ALP.It negatively correlated with lumbar spine and hip BMDs(P<0.05).CONCLUSION Inflammatory and bone metabolic levels in patients with DN were found to be associated with the gut microbiota–derived metabolite TMAO.Elevated TMAO levels may mediate inflammatory responses and bone metabolism disorders in patients with DN,thereby contributing to the progression of systemic inflammation and OP.展开更多
Straight-chain aliphatic tert-amine N-oxides were found to be useful oxidizing agent for epoxidation of tri- and tetra-substituted perfluoroalkenes under mild conditions in high yields. The process for epoxidation by ...Straight-chain aliphatic tert-amine N-oxides were found to be useful oxidizing agent for epoxidation of tri- and tetra-substituted perfluoroalkenes under mild conditions in high yields. The process for epoxidation by employing tri-n-butylamine N-oxide gave the best result in the reagent survey.展开更多
BACKGROUND Trimethylamine N-oxide (TMAO) has been shown to be involved in cardiovascular disease (CVD). However, its role in nonalcoholic steatohepatitis (NASH) is unknown. AIM To determine the effect of TMAO on the p...BACKGROUND Trimethylamine N-oxide (TMAO) has been shown to be involved in cardiovascular disease (CVD). However, its role in nonalcoholic steatohepatitis (NASH) is unknown. AIM To determine the effect of TMAO on the progression of NASH. METHODS A rat model was induced by 16-wk high-fat high-cholesterol (HFHC) diet feeding and TMAO was administrated by daily oral gavage for 8 wk. RESULTS Oral TMAO intervention attenuated HFHC diet-induced steatohepatitis in rats. Histological evaluation showed that TMAO treatment significantly alleviated lobular inflammation and hepatocyte ballooning in the livers of rats fed a HFHC diet. Serum levels of alanine aminotransferase and aspartate aminotransferase were also decreased by TMAO treatment. Moreover, hepatic endoplasmic reticulum (ER) stress and cell death were mitigated in HFHC diet-fed TMAOtreated rats. Hepatic and serum levels of cholesterol were both decreased by TMAO treatment in rats fed a HFHC diet. Furthermore, the expression levels of intestinal cholesterol transporters were detected. Interestingly, cholesterol influxrelated Niemann-Pick C1-like 1 was downregulated and cholesterol efflux-related ABCG5/8 were upregulated by TMAO treatment in the small intestine. Gut microbiota analysis showed that TMAO could alter the gut microbial profile and restore the diversity of gut flora. CONCLUSION These data suggest that TMAO may modulate the gut microbiota, inhibit intestinal cholesterol absorption, and ameliorate hepatic ER stress and cell death under cholesterol overload, thereby attenuating HFHC diet-induced steatohepatitis in rats. Further studies are needed to evaluate the influence on CVD and define the safe does of TMAO treatment.展开更多
The title zinc（Ⅱ） complex salt [Zn（H2O）6]（ClO4）2-（PNOS）4, where PNOS is derived from picolinaldehyde N-oxide with semicarbazone, has been prepared and structurally characterized by X-ray single-crystal analys...The title zinc（Ⅱ） complex salt [Zn（H2O）6]（ClO4）2-（PNOS）4, where PNOS is derived from picolinaldehyde N-oxide with semicarbazone, has been prepared and structurally characterized by X-ray single-crystal analysis. It crystallizes in triclinic, space group PI with a = 7.529（3）, b = 10.206（4）, c = 14.678（6）A, a = 86.293（6）, β= 87.686（7）, γ= 81.382（6）°, C28H44Cl2N16O22Zn, Mr = 1093.06, V = 1112.3（8） ,A^3 Z = 1, Dc = 1.632 g/cm^3, S = 1.089, μ（MoKa） = 0.773 mm^-1, F（000） = 564, the final R = 0.0438 and wR = 0.1076 for 3888 independent reflections with Rint = 0.0224. The crystal structure possesses a [Zn（H2O）6]^2＋ cation, two ClO4^- anions and four PNOSs. In the crystal structure, Zn^2＋ cation is located at the symcenter and coordinated by six water molecules. In [Zn（H2O）6]^2＋, an elongate octahedral complex cation, the average Zn-O bond length is 2.087（2） A. There exist a lot of H bonds in the structure, linking the cation [Zn（H2O）6]^2＋, anion ClO4^- and PNOS to form a 3D network.展开更多
A new complex [Cd（H2biim）2（H2O）2]·（ino）2·4H2O （H2biim = 2,2＇-biimidazole, ino = isonicotinate-N-oxide） has been prepared and characterized by single-crystal X-ray diffraction analysis, IR and fluore...A new complex [Cd（H2biim）2（H2O）2]·（ino）2·4H2O （H2biim = 2,2＇-biimidazole, ino = isonicotinate-N-oxide） has been prepared and characterized by single-crystal X-ray diffraction analysis, IR and fluorescence spectra analysis. The crystal is of triclinic system, space group P1 with a = 7.5380（6）, b = 8.0402（7）, c = 13.5094（11） , α = 104.269（1）, β = 93.604（1）, γ = 98.349（1）°, V = 780.93（11） 3, Mr = 765.00, Dc = 1.627 g/cm3, F（000） = 390, μ = 0.776 mm-1 and Z = 1. The final R = 0.0322 and wR = 0.0825 for 7038 observed reflections with I 2σ（I） and R = 0.0341 and wR = 0.0832 for all data. The title complex exhibits an infinite chain-like structure through bridging isonicotinate-N-oxide. Strong interchain hydrogen bonds between isonicotinate-N-oxide and H2biim result in the robust 3-D supramolecular architecture. Moreover, the complex shows strong photoluminescence with emission maximum at λ = 401 nm upon λex = 330 nm.展开更多
AIM:To provide the direct evidence for the crucial role of trimethylamine N-oxide(TMAO)in vascular permeability and endothelial cell dysfunction under diabetic condition.METHODS:The role of TMAO on the in vitro biolog...AIM:To provide the direct evidence for the crucial role of trimethylamine N-oxide(TMAO)in vascular permeability and endothelial cell dysfunction under diabetic condition.METHODS:The role of TMAO on the in vitro biological effect of human retinal microvascular endothelial cells(HRMEC)under high glucose conditions was tested by a cell counting kit,wound healing,a transwell and a tube formation assay.The inflammation-related gene expression affected by TMAO was tested by real-time polymerase chain reaction(RT-PCR).The expression of the cell junction was measured by Western blotting(WB)and immunofluorescence staining.In addition,two groups of rat models,diabetic and non-diabetic,were fed with normal or 0.1%TMAO for 16wk,and their plasma levels of TMAO,vascular endothelial growth factor(VEGF),interleukin(IL)-6 and tumor necrosis factor(TNF)-αwere tested.The vascular permeability of rat retinas was measured using FITC-Dextran,and the expression of zonula occludens(ZO)-1 and claudin-5 in rat retinas was detected by WB or immunofluorescence staining.RESULTS:TMAO administration significantly increased the cell proliferation,migration,and tube formation of primary HRMEC either in normal or high-glucose conditions.RT-PCR showed elevated inflammation-related gene expression of HRMEC under TMAO stimulation,while WB or immunofluorescence staining indicated decreased cell junction ZO-1 and occludin expression after high-glucose and TMAO treatment.Diabetic rats showed higher plasma levels of TMAO as well as retinal vascular leakage,which were even higher in TMAO-feeding diabetic rats.Furthermore,TMAO administration increased the rat plasma levels of VEGF,IL-6 and TNF-αwhile decreasing the retinal expression levels of ZO-1 and claudin-5.CONCLUSION:TMAO enhances the proliferation,migration,and tube formation of HRMEC,as well as destroys their vascular integrity and tight connection.It also regulates the expression of VEGF,IL-6,and TNF-α.展开更多
AIM: The application of strychnine(S) is limited due to its toxicity; strychnine N-oxide(SNO) is a derivative of strychnine. The aim was to employ zebrafish embryos to investigate and compare the developmental toxicit...AIM: The application of strychnine(S) is limited due to its toxicity; strychnine N-oxide(SNO) is a derivative of strychnine. The aim was to employ zebrafish embryos to investigate and compare the developmental toxicity induced by S and SNO. METHODS: The toxicity of S and SNO was examined through the hatching rate and survival rate. Morphological changes of the zebrafish were observed with a dissecting microscope. Apoptosis was detected through acridine orange(AO) staining and flow cytometry. Apoptotic genes were measured by RT-PCR. RESULTS: Embryo malformation was observed in the embryos exposed to S at 200 μmol·L–1. When SNO concentration was increased to 1 mmol·L–1, scoliolosis, and pericardial edema could be seen in some embryos. Results from fluorescence microscopy and flow cytometry analysis showed that S at 200 μmol·L–1 induced apoptosis, whereas the apoptotic rate in the SNO-treated group(200 μmol·L–1) was much lower than that in the S group. RT-PCR analysis showed that p53 mRNA expression and the ratio of Bax/Bcl-2 in the S group were significantly altered compared with the control group(*P < 0.05). Moreover, Bax mRNA expression in both S and SNO group were significantly different from that in the control group(**P <0.01). CONCLUSION: These results lead to the conclusion that SNO has significantly lower toxicity than S in zebrafish embryos.展开更多
The complex Mn(apo)6Cl2 (apo=2-aminopyridine N-oxide) was obtained by the reaction of MnCl2(4H2O with apo(HCl and NaOH in ethanol. A single-crystal X-ray study shows that the complex is mononuclear with octahedral coo...The complex Mn(apo)6Cl2 (apo=2-aminopyridine N-oxide) was obtained by the reaction of MnCl2(4H2O with apo(HCl and NaOH in ethanol. A single-crystal X-ray study shows that the complex is mononuclear with octahedral coordination environment (MnC30H36N12O6Cl2). The oxygen atoms from apo ligands coordinate to the manganese atom forming Mn(apo)6Cl2. The compound Mn(apo)6Cl2 is hexagonally symmetric with space group R3, lattice constants: a = 12.010(2), b = 12.010(2), c = 20.232(4) ?, ( = 120(, V= 2527.4(7) ?3, Z=3, Mr =786.55, Dc=1.550 g/cm3, (= 0.614mm-1, F(000) = 1221, R = 0.0541, Rw = 0.0580 for 1229 reflections with I>2((I). The distances between Mn(II) and O atoms are in the range from 2.171(5) to 2.184(5) ?, and the distance between the chlorine anion and N atom of amido group is 3.3 ?. The dihedral angle between two adjacent pyridine ring planes is 59.19 (0.17)°.展开更多
基金This work was supported by the Natural Science Foundation of Nanjing Institute of Technology （YKJ201507, CKJA201603） and the Youth Natural Sci- ence Foundation of Jiangsu Province （BK20160774）, and Outstanding Scientific and Technological Innovation Team in Colleges and Universities of Jiangsu Province.
文摘Based on the parent tetrazole 2N-oxide, six series of novel carbon-linked ditetrazole 2N- oxides with different energetic substituent groups （-NH2, -Na, -NO2, NF2, -NHNO2） and energetic bridge groups （-CH2-, -CH2-CH2-, -NH-, -N=N-, -NH-NH-） were designed. The overall performance and the effects of different energetic substituent groups and energetic bridge groups on the performance were investigated by density functional theory and electrostatic potential methods. The results showed that most of designed compounds have oxygen balance around zero, high heats of formation, high density, high energy, and acceptable sensitivity, indicating that tetrazole N-oxide is a useful parent energetic compound employed for obtaining high energy compounds, even only combined with some very common energetic substituent groups and bridge groups. Comprehensively considering the effects on energy and sensitivity, the -NO2, -NF2, -NH- and-NH-NH- are appropriate substituent groups for combining tetrozale N-oxide to design new energetic compounds, while -NH2, -Na, -CH2-CH2-, and -N=N- are inappropriate.
基金financial support from the Hunan Provincial Natural Science Foundation of China (No.2019JJ20008)
文摘An eco-friendly protocol for the synthesis of various 2-sulfonyl quinolines/pyridines through sulfonylation of heteroaromatic N-oxides with sodium sulfinates in water at ambient temperature under metal-and oxidant-free conditions has been developed.The mild reaction conditions,high reaction efficiency,operational simplicity,short reaction time and remarkable functional-group compatibility make the developed protocol very attractive for the preparation of 2-sulfonyl N-heteroaromatic compounds.
基金financial support from the National Natural Science Foundation of China(No.21276043)
文摘We report a practical and highly efficient protocol for the arylation of pyridine N-oxides with arylboronic acid through palladium-catalyzed Suzuki reaction in water.This ligand-free Suzuki reaction is performed in the presence of diisopropylamine and gives 2-or 3-arylated pyridyl N-oxide derivatives in good to excellent yields within 1 h.
文摘A new preparation method of the N-ethyl 7,17-seco C_(19)-diterpenoid alkaloids(5)and(6)by pyrolysis of the N-oxides(3)and(4),respectively, in anhydrous diglyme is described.A probable reaction mechanism for the pyroly- sis is presented and studied preliminarily.
基金financial support from the National Nature Science Foundation of China(Nos. 21432009, 21672200, 21472177,21772185)the assistance of the product characterization from the Chemistry Experiment Teaching Center of University of Science and Technology of Chinasupported by the Strategic Priority Research Program of the Chinese Academy of Sciences(No. XDB20000000)
文摘A highly enantioselective Michael addition of nitro esters to 2-enoyl-pyridine N-oxides was developed by using chiral copper catalysts. The Michael addition products can be obtained in high yields and with up to 96% ee. Moreover, asymmetric Michael addition product of nitromethane to 2-enoyl-pyridine N-oxides can be obtained in one step. An analogue of nicotine, dihydro-2H-pyrrol 4b was synthesized with this developed method.
基金supported by the National Natural Science Foundation of China (21402103, 21772107)the China Postdoctoral Science Foundation (150030)+1 种基金the Research Fund of Qingdao Agricultural University’s Highlevel Person (631303)Shandong province key research and development plan(GG201809130228)~~
文摘A simple and efficient method for the synthesis of 2-sulfonylquinoline from deoxygenative C2-sulfonylation of quinoline N-oxides with sulfinic acid induced by visible light is presented.This protocol shows a broad substrate scope,and desired products with various substituents can be formed in moderate to high yields at room temperature.
基金the National Natural Science Foundation of China(Nos.21977056,21732002,21672117,21602117,21772104,31760527)the Tianjin Natural Science Foundation(No.16JCZDJC32400)for generous financial support for our programs。
文摘Herein,we report the first Rh~Ⅲ-catalyzed regioselective C8 arylation of quinoline N-oxides with commercially available arylboronic acids as coupling partners.This procedure is simple,and the reaction shows perfect regioselectivity,a broad substrate scope,and isolated yields of up to 92%.We demonstrate the utility of the reaction by using it for late-stage functionalization of a fungicide.
文摘New solid complexes of europium, uranyl and zinc ions with N-oxides of 4-chloro-2,6-dimethylpyridine, quinoline and 4-meth- oxyquinaldinic acid in presence different anions were obtained and characterized by elemental and TG analyses, IR and luminescence spectra. The compounds are crystalline, hydrated or anhydrous salts with colours typical of metal ions. Thermal studies showed that in hydrated salts lattice or coordination water molecules are present. A role of different anions in the formation of various types of the complexes is presented.
基金the National Key Research and Development Program of China(2022YFC2303100)the National Natural Science Foundation of China(22271300,21702119)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDBO610000)the Youth Innovation Team Project of Shandong Provincial College(2022KJ180)the High-level Talent Research Start-up Project Funding of Henan Academy of Sciences(242002063)for financial support.
文摘A KOtBu-mediated C2-benzylation of quinoline N-oxides with benzylboronates under mild reaction conditions has been developed.The reaction shows broad scope for both of the quinoline N-oxides and benzylboronates,especially,secondary and tertiary benzylboronates are also compatible with this reaction.DFT calculations indicate that the reaction is promoted by the nucleophilic addition of KOtBu to boronate rather than the deprotonation of benzylic C−H bond with KOtBu.
基金Project supported by the National Natural Science Foundation of China
文摘Aliphatic amine N-oxides, particularly （CH<sub>3</sub>）<sub>3</sub>NO, have been widely used as O-atom transfer reagents in organometallic chemistry. Recently the systematic kinetic studies on O-atom transfer reactions have been reported in detail. However, little is known about the use of pyridine N-oxides and the related aromatic amine N-oxides as O-atom transfer reagents in organometallic chemistry, and no kinetic or
基金supported by the National Natural Science Foundation of China(21871160,21672121,22071130)the fellowship of Tsinghua-Peking Centre for Life Sciences(CLS).
文摘A highly efficient enantioselective construction of heterobiaryl N-oxides was developed.A series of axially chiral heterobiaryl N-oxides were generated via the cascade reaction of aminobenzamides with heterobiaryl aldehydes in the presence of chiral phosphoric acids.A number of atropisomers were afforded in moderate to good yields with excellent enantioselectivities and diastereoselectivities.Preliminary results demonstrate that the heterobiaryl N-oxides can be utilized as efficient chiral ligands in asymmetric catalysis.
基金Project supported by the National Natural Science Foundation of China （Nos. 20172028 and 20421202） and the Trans-Century Training Programme Foundation for the Talents by the State Education Commission （No. 2002-48）.
文摘Novel phenylene-bridged zinc bisporphyrins （1-4）, fulleropyrrolidines （C60-m, C60-h） and their N-oxides （C60-mo, C60-ho） were synthesized. The fluorescence quenching processes of bisporphyrins in toluene solution by fulleropyrrolidines and their N-oxides were investigated by steady-state fluorescence spectra. The fluorescence quenching constants proved that the fluorescence quenching ability was decreased as reduction of the pyrrolidine functional groups of fullerene surface： C60-h〉C60-m〉C60, and the fluorescence quenching ability was increased about 1.3-7.4 times by utilizing fulleropyrrolidine N-oxides （C60-mo, C60-ho） compared to fulleropyrrolidine compounds （C60-m, C60-h）. The results revealed photoinduced electron transfer （PET） efficiency between bispor-phyrin and fullerene derivatives could be tunable by change of functional groups on fullerene surface.
文摘BACKGROUND Diabetic nephropathy(DN)is one of the most serious microvascular complications of type 2 diabetes mellitus(T2DM),and its incidence increases with the global rise in diabetes prevalence.It is the leading cause of chronic kidney disease and end-stage kidney disease.Patients with DN often experience complex metabolic disorders and chronic inflammatory states,which not only accelerate the decline of renal function but are also closely related to complications such as cardiovascular events and osteoporosis(OP),seriously compromising quality of life.With the in-depth research on the gut microbiota and the emergence of concepts such as the"gut-kidney axis"and the"enteric-bone axis",the key roles of the gut microbiota and its metabolites in metabolic disorders,inflammatory responses,and target organ damage have been increasingly recognized.However,the specific role of gut microbiota in the pathogenesis of DN remains to be further explored.The results obtained may provide evidence to better understand the pathogenesis of DN and to identify high-risk populations at an early stage.This research direction is of strategic significance.AIM To assess the correlation of the gut microbiota metabolite trimethylamine N-oxide(TMAO)with inflammatory marker levels and OP in patients with DN.METHODS A total of 115 patients diagnosed with type 2 DN and treated at the Department of Endocrinology,Second Affiliated Hospital of Shandong First Medical University from August 2022 to December 2024 were enrolled in the DN group,and 115 patients with T2DM without nephropathy were included in the T2DM group.The two groups were compared in terms of gastrointestinal microbiota abundance and relative abundance at the genus level;levels of TMAO,inflammatory markers[including C-reactive protein(CRP),interleukin-6(IL-6),interleukin-8(IL-8),and tumor necrosis factor-α(TNF-α)],and bone metabolism markers[including procollagen type I N-terminal propeptide(PINP),β-CrossLaps(β-CTX),and alkaline phosphatase(ALP)];and lumbar spine and hip bone mineral density(BMD).The correlation of TMAO level with inflammatory factor and bone metabolism indicator levels was further analyzed.RESULTS The DN group had higher Chao1 and Simpson indices of gastrointestinal microbiota diversity than the T2DM group,whereas the ACE and Shannon indices were lower(P<0.05).The relative abundance of Firmicutes was higher,and the relative abundances of Bacteroidetes,Proteobacteria,and Actinobacteria were lower in the DN group than in the T2DM group(P<0.05).CRP,IL-6,IL-8,TNF-α,and TMAO levels were considerably elevated in the DN group compared to the T2DM group(P<0.05).Moreover,the DN group had higher levels of bone turnover markers-including PINP,β-CTX,and ALP-but lower lumbar spine and hip BMDs than the T2DM group(P<0.05).TMAO level positively correlated with the Chao1 and Simpson indices and negatively correlated with the ACE and Shannon indices of gut microbiota diversity.TMAO level also negatively correlated with the relative abundances of Bacteroidetes,Proteobacteria,and Actinobacteria and positively correlated with the abundance of Firmicutes.Additionally,TMAO level positively correlated with the inflammatory markers CRP,IL-6,IL-8,and TNF-α,as well as with the bone turnover markers PINP,β-CTX,and ALP.It negatively correlated with lumbar spine and hip BMDs(P<0.05).CONCLUSION Inflammatory and bone metabolic levels in patients with DN were found to be associated with the gut microbiota–derived metabolite TMAO.Elevated TMAO levels may mediate inflammatory responses and bone metabolism disorders in patients with DN,thereby contributing to the progression of systemic inflammation and OP.
文摘Straight-chain aliphatic tert-amine N-oxides were found to be useful oxidizing agent for epoxidation of tri- and tetra-substituted perfluoroalkenes under mild conditions in high yields. The process for epoxidation by employing tri-n-butylamine N-oxide gave the best result in the reagent survey.
基金Supported by National Key R and D Program of China,No.2017YFC0908903National Natural Science Foundation of China,No.81873565,No.81470840,and No.81800510Shanghai Sailing Program,No.18YF1415900
文摘BACKGROUND Trimethylamine N-oxide (TMAO) has been shown to be involved in cardiovascular disease (CVD). However, its role in nonalcoholic steatohepatitis (NASH) is unknown. AIM To determine the effect of TMAO on the progression of NASH. METHODS A rat model was induced by 16-wk high-fat high-cholesterol (HFHC) diet feeding and TMAO was administrated by daily oral gavage for 8 wk. RESULTS Oral TMAO intervention attenuated HFHC diet-induced steatohepatitis in rats. Histological evaluation showed that TMAO treatment significantly alleviated lobular inflammation and hepatocyte ballooning in the livers of rats fed a HFHC diet. Serum levels of alanine aminotransferase and aspartate aminotransferase were also decreased by TMAO treatment. Moreover, hepatic endoplasmic reticulum (ER) stress and cell death were mitigated in HFHC diet-fed TMAOtreated rats. Hepatic and serum levels of cholesterol were both decreased by TMAO treatment in rats fed a HFHC diet. Furthermore, the expression levels of intestinal cholesterol transporters were detected. Interestingly, cholesterol influxrelated Niemann-Pick C1-like 1 was downregulated and cholesterol efflux-related ABCG5/8 were upregulated by TMAO treatment in the small intestine. Gut microbiota analysis showed that TMAO could alter the gut microbial profile and restore the diversity of gut flora. CONCLUSION These data suggest that TMAO may modulate the gut microbiota, inhibit intestinal cholesterol absorption, and ameliorate hepatic ER stress and cell death under cholesterol overload, thereby attenuating HFHC diet-induced steatohepatitis in rats. Further studies are needed to evaluate the influence on CVD and define the safe does of TMAO treatment.
基金Natural Science Foundation and Education Department Foundation of Guangxi Province
文摘The title zinc（Ⅱ） complex salt [Zn（H2O）6]（ClO4）2-（PNOS）4, where PNOS is derived from picolinaldehyde N-oxide with semicarbazone, has been prepared and structurally characterized by X-ray single-crystal analysis. It crystallizes in triclinic, space group PI with a = 7.529（3）, b = 10.206（4）, c = 14.678（6）A, a = 86.293（6）, β= 87.686（7）, γ= 81.382（6）°, C28H44Cl2N16O22Zn, Mr = 1093.06, V = 1112.3（8） ,A^3 Z = 1, Dc = 1.632 g/cm^3, S = 1.089, μ（MoKa） = 0.773 mm^-1, F（000） = 564, the final R = 0.0438 and wR = 0.1076 for 3888 independent reflections with Rint = 0.0224. The crystal structure possesses a [Zn（H2O）6]^2＋ cation, two ClO4^- anions and four PNOSs. In the crystal structure, Zn^2＋ cation is located at the symcenter and coordinated by six water molecules. In [Zn（H2O）6]^2＋, an elongate octahedral complex cation, the average Zn-O bond length is 2.087（2） A. There exist a lot of H bonds in the structure, linking the cation [Zn（H2O）6]^2＋, anion ClO4^- and PNOS to form a 3D network.
基金supported by the National Natural Science Foundation of China (No. 20772042)
文摘A new complex [Cd（H2biim）2（H2O）2]·（ino）2·4H2O （H2biim = 2,2＇-biimidazole, ino = isonicotinate-N-oxide） has been prepared and characterized by single-crystal X-ray diffraction analysis, IR and fluorescence spectra analysis. The crystal is of triclinic system, space group P1 with a = 7.5380（6）, b = 8.0402（7）, c = 13.5094（11） , α = 104.269（1）, β = 93.604（1）, γ = 98.349（1）°, V = 780.93（11） 3, Mr = 765.00, Dc = 1.627 g/cm3, F（000） = 390, μ = 0.776 mm-1 and Z = 1. The final R = 0.0322 and wR = 0.0825 for 7038 observed reflections with I 2σ（I） and R = 0.0341 and wR = 0.0832 for all data. The title complex exhibits an infinite chain-like structure through bridging isonicotinate-N-oxide. Strong interchain hydrogen bonds between isonicotinate-N-oxide and H2biim result in the robust 3-D supramolecular architecture. Moreover, the complex shows strong photoluminescence with emission maximum at λ = 401 nm upon λex = 330 nm.
基金Supported by the National Natural Science Foundation in China(No.81671641)Jiangsu Provincial Medical Innovation Team(No.CXTDA2017039)Gusu Health Talents Program(No.GSWS 2022018).
文摘AIM:To provide the direct evidence for the crucial role of trimethylamine N-oxide(TMAO)in vascular permeability and endothelial cell dysfunction under diabetic condition.METHODS:The role of TMAO on the in vitro biological effect of human retinal microvascular endothelial cells(HRMEC)under high glucose conditions was tested by a cell counting kit,wound healing,a transwell and a tube formation assay.The inflammation-related gene expression affected by TMAO was tested by real-time polymerase chain reaction(RT-PCR).The expression of the cell junction was measured by Western blotting(WB)and immunofluorescence staining.In addition,two groups of rat models,diabetic and non-diabetic,were fed with normal or 0.1%TMAO for 16wk,and their plasma levels of TMAO,vascular endothelial growth factor(VEGF),interleukin(IL)-6 and tumor necrosis factor(TNF)-αwere tested.The vascular permeability of rat retinas was measured using FITC-Dextran,and the expression of zonula occludens(ZO)-1 and claudin-5 in rat retinas was detected by WB or immunofluorescence staining.RESULTS:TMAO administration significantly increased the cell proliferation,migration,and tube formation of primary HRMEC either in normal or high-glucose conditions.RT-PCR showed elevated inflammation-related gene expression of HRMEC under TMAO stimulation,while WB or immunofluorescence staining indicated decreased cell junction ZO-1 and occludin expression after high-glucose and TMAO treatment.Diabetic rats showed higher plasma levels of TMAO as well as retinal vascular leakage,which were even higher in TMAO-feeding diabetic rats.Furthermore,TMAO administration increased the rat plasma levels of VEGF,IL-6 and TNF-αwhile decreasing the retinal expression levels of ZO-1 and claudin-5.CONCLUSION:TMAO enhances the proliferation,migration,and tube formation of HRMEC,as well as destroys their vascular integrity and tight connection.It also regulates the expression of VEGF,IL-6,and TNF-α.
基金supported by The Opening Project of Jiangsu Key Laboratory for Chinese Medicine Processing(ZYPZ010)the National Natural Science Foundation of China(81373295)
文摘AIM: The application of strychnine(S) is limited due to its toxicity; strychnine N-oxide(SNO) is a derivative of strychnine. The aim was to employ zebrafish embryos to investigate and compare the developmental toxicity induced by S and SNO. METHODS: The toxicity of S and SNO was examined through the hatching rate and survival rate. Morphological changes of the zebrafish were observed with a dissecting microscope. Apoptosis was detected through acridine orange(AO) staining and flow cytometry. Apoptotic genes were measured by RT-PCR. RESULTS: Embryo malformation was observed in the embryos exposed to S at 200 μmol·L–1. When SNO concentration was increased to 1 mmol·L–1, scoliolosis, and pericardial edema could be seen in some embryos. Results from fluorescence microscopy and flow cytometry analysis showed that S at 200 μmol·L–1 induced apoptosis, whereas the apoptotic rate in the SNO-treated group(200 μmol·L–1) was much lower than that in the S group. RT-PCR analysis showed that p53 mRNA expression and the ratio of Bax/Bcl-2 in the S group were significantly altered compared with the control group(*P < 0.05). Moreover, Bax mRNA expression in both S and SNO group were significantly different from that in the control group(**P <0.01). CONCLUSION: These results lead to the conclusion that SNO has significantly lower toxicity than S in zebrafish embryos.
文摘The complex Mn(apo)6Cl2 (apo=2-aminopyridine N-oxide) was obtained by the reaction of MnCl2(4H2O with apo(HCl and NaOH in ethanol. A single-crystal X-ray study shows that the complex is mononuclear with octahedral coordination environment (MnC30H36N12O6Cl2). The oxygen atoms from apo ligands coordinate to the manganese atom forming Mn(apo)6Cl2. The compound Mn(apo)6Cl2 is hexagonally symmetric with space group R3, lattice constants: a = 12.010(2), b = 12.010(2), c = 20.232(4) ?, ( = 120(, V= 2527.4(7) ?3, Z=3, Mr =786.55, Dc=1.550 g/cm3, (= 0.614mm-1, F(000) = 1221, R = 0.0541, Rw = 0.0580 for 1229 reflections with I>2((I). The distances between Mn(II) and O atoms are in the range from 2.171(5) to 2.184(5) ?, and the distance between the chlorine anion and N atom of amido group is 3.3 ?. The dihedral angle between two adjacent pyridine ring planes is 59.19 (0.17)°.
