Oxiranes as well as four and five membered rings of cyclic ethers were cleaved with acyl chloride in the presence of samarium trichloride or Eu(hfe)_3 as Lewis-acid catalyst under mild conditions,the oorresponding chl...Oxiranes as well as four and five membered rings of cyclic ethers were cleaved with acyl chloride in the presence of samarium trichloride or Eu(hfe)_3 as Lewis-acid catalyst under mild conditions,the oorresponding chloroesters were obtained readily and smoothly in excellent yields.展开更多
Comprehensive Summary Phthalides serve as core structures pervasive in a wide array of natural products and drug molecules,which display a diverse array of biological activities.We report herein a highly efficient dyn...Comprehensive Summary Phthalides serve as core structures pervasive in a wide array of natural products and drug molecules,which display a diverse array of biological activities.We report herein a highly efficient dynamic kinetic resolution of 3-hydroxyphthalides by chiral isothioureas(ITUs)catalyzed asymmetric acylation,facilitating the effective synthesis of a variety of chiral phthalidyl esters with good yields and enantioselectivities.Notably,this reaction features mild reaction conditions,expansive substrate scope as well as good functional group compatibility.In addition,the practicality of this method is underscored by the large-scale synthesis,reduced catalyst loading experiment and the synthesis of the chiral phthalidyl ester prodrug.展开更多
Indole[2,1-α]isoquinolines are an important class of bioactive molecules and show good antibacterial activity.In the present study,an efficient copper(I)-catalyzed acylation/cyclization has been developed for the con...Indole[2,1-α]isoquinolines are an important class of bioactive molecules and show good antibacterial activity.In the present study,an efficient copper(I)-catalyzed acylation/cyclization has been developed for the construction of indolo[2,1-α]isoquinoline derivatives by utilizing 2-aryl-N-acryloyl indole and benzohydrazide as reactants in the presence of CuI as catalyst and tert-butyl hydroperoxide as oxidant.The present protocol exhibits good functional group tolerance,and a series of acylated indole[2,1-α]isoquinolines were synthesized in moderate to good yields.Radical trapping experiments indicated that the reaction may involve a radical process.展开更多
Highly toxic phosgene,diethyl chlorophosphate(DCP)and volatile acyl chlorides endanger our life and public security.To achieve facile sensing and discrimination of multiple target analytes,herein,we presented a single...Highly toxic phosgene,diethyl chlorophosphate(DCP)and volatile acyl chlorides endanger our life and public security.To achieve facile sensing and discrimination of multiple target analytes,herein,we presented a single fluorescent probe(BDP-CHD)for high-throughput screening of phosgene,DCP and volatile acyl chlorides.The probe underwent a covalent cascade reaction with phosgene to form boron dipyrromethene(BODIPY)with bright green fluorescence.By contrast,DCP,diphosgene and acyl chlorides can covalently assembled with the probe,giving rise to strong blue fluorescence.The probe has demonstrated high-throughput detection capability,high sensitivity,fast response(within 3 s)and parts per trillion(ppt)level detection limit.Furthermore,a portable platform based on BDP-CHD was constructed,which has achieved high-throughput discrimination of 16 analytes through linear discriminant analysis(LDA).Moreover,a smartphone adaptable RGB recognition pattern was established for the quantitative detection of multi-analytes.Therefore,this portable fluorescence sensing platform can serve as a versatile tool for rapid and high-throughput detection of toxic phosgene,DCP and volatile acyl chlorides.The proposed“one for more”strategy simplifies multi-target discrimination procedures and holds great promise for various sensing applications.展开更多
Polyhydroxyalkanoate(PHA),a well-known biodegradable polymer,featuresβ-lactones as its monomers,which can be selectively synthesized through ring-expansion carbonylation of epoxides using well-defined[Lewis acid]^(+)...Polyhydroxyalkanoate(PHA),a well-known biodegradable polymer,featuresβ-lactones as its monomers,which can be selectively synthesized through ring-expansion carbonylation of epoxides using well-defined[Lewis acid]^(+)[Co(CO)_(4)]^(-)catalysts.However,the decomposition of[Co(CO)_(4)]^(-)species at temperatures exceeding 80℃presents a hurdle for the development of commercially viable processes under high-temperature reaction conditions to reduce reaction time.Drawing insights from stable{(acyl)Co(CO)n}intermediates involved in historical HCo(CO)_(4)-catalyzed hydroformylation processes,we sought to the high-temperature catalytic activity of epoxide ring-expansion carbonylation.The developed catalyst system,[(acetyl)Co(CO)_(2)dppp]and[(TPP)CrCl],exhibited exceptional catalytic performance with an unprecedented initial turnover frequency of 4700 h^(-1)at 100℃and a turnover numbers of 93000.Notably,the catalyst displayed outstanding stability,operating at 80℃for 168 h while selectively generatingβ-lactones.展开更多
Mechanistic studies of the cleavage and transformation of unactivated C_(sp3)-H bonds are a significant field of chemistry.Overcoming the inherent low acidity of C-H bonds to activate the inert substrates is challenge...Mechanistic studies of the cleavage and transformation of unactivated C_(sp3)-H bonds are a significant field of chemistry.Overcoming the inherent low acidity of C-H bonds to activate the inert substrates is challenge under mild conditions.And their complex multi-step transformations may also hinder mechanistic understanding.Herein,we perform theoretical calculations and experimental studies to explore the C_(sp3)-H bonds activation and acylation mechanisms of toluene/thioether using the relatively weak base LDA.A synergistic"main and auxiliary"model was revealed involving dual lithium metal by LDA dimers,and the aryl dilithium species as an intermediate base can facilitate C_(sp3)-H activation.This model not only aids in understanding the acidity of unactivated C_(sp3)-H bonds and the nucleophilicity of their conjugate bases for their kinetic control through cooperative interactions,but also predicts unusual kinetic isotope effects(KIE)for newly designed 2-(methylthio)naphthalene that are experimentally validated.This research is expected to provide a crucial scenario for the cleavage and transformation of unactivated C_(sp3)-H bonds and the development of new functionalities for alkali metal reagents.展开更多
The regioselective acylation of unprotected phenylethyl glucoside withcinnamoyl chloride leads to 6-OH cin-namoylated glucoside. In this manner, thirteen phenylpropanoidglycoside analogs were designed and prepared. Th...The regioselective acylation of unprotected phenylethyl glucoside withcinnamoyl chloride leads to 6-OH cin-namoylated glucoside. In this manner, thirteen phenylpropanoidglycoside analogs were designed and prepared. Their structure was confirmed by ~1H NMR and ^(13)CNMR spectra.展开更多
Several phenylselenyl esters were selected as precursors of acyl radicals and synthesised by our established method. Treatment of these phenylselenyl esters with tributyltinhydride and AIBN ge...Several phenylselenyl esters were selected as precursors of acyl radicals and synthesised by our established method. Treatment of these phenylselenyl esters with tributyltinhydride and AIBN generated the corresponding acyl radicals, which were found to proceed in 5 exo trig or 6 endo trig cyclisations to afford high yields of cyclopentanones and cyclohexanones, The substitution groups on the substrates have played an important role on the regioselectivity of cyclisations.展开更多
A support made of mussel-inspired polydopamine-coated magnetic iron oxide nanoparticles （PD-MNPs） was prepared and characterized. The widely used Aspetyillus niger lipase （ANL） was immobilized on the PD-MNPs （ANL...A support made of mussel-inspired polydopamine-coated magnetic iron oxide nanoparticles （PD-MNPs） was prepared and characterized. The widely used Aspetyillus niger lipase （ANL） was immobilized on the PD-MNPs （ANL@PD-MNPs） with a protein loading of 138 mg/g and an activity recovery of 83.6% under optimized conditions. For the immobilization, the pH and immobilization time were investigated. The pH and thermal and storage stability of the ANL@PD-MNPs significant- ly surpassed those of free ANL. The ANL@PD-MNPs had better solvent tolerance than free ANL. The secondary structure of free ANL and ANL@PD-MNPs was analyzed by infrared spectroscopy, A kinetic study demonstrated that the ANL@PD-MNPs had enhanced enzyme-substrate affinity and high catalytic efficiency. The ANL@PD-MNPs was applied as a biocatalyst for the regioselective acylation of dihydromyricetin （DMY） in DMSO and gave a conversion of 79.3%, which was higher than that of previous reports. The ANL@PD-MNPs retained over 55% of its initial activity after 10 cycles of reuse. The ANL@PD-MNPs were readily separated from the reaction system by a magnet. The PD-MNPs is an excellent support for ANL and the resulting ANL@PD-MNPs displayed good potential for the efficient synthesis of dihydromyricetin-3-acetate by enzymatic regioselective acylation.展开更多
By analyzing the key steps that restricted the industrial synthesis of salidroside, selective protection of tyrosol with different acylation reagents was adopted. The strategy facilitated the crystallization of interm...By analyzing the key steps that restricted the industrial synthesis of salidroside, selective protection of tyrosol with different acylation reagents was adopted. The strategy facilitated the crystallization of intermediates, which allowed the scalable synthesis of salidroside. It included a reaction of penta-O-acetyl-β-D-glucose with acyl protected tyrosol in the presence of Lewis acid catalyst（ZnCl2）, followed by deacylation under basic condition（NaOMe/MeOH） to give the salidroside. The total yield of this three-step reaction was 47%. Final product and intermediates were purified by recrystallization, which significantly reduced the cost and made the large scale synthesis feasible.展开更多
As important constitutes in many drugs, piperazine comprised compounds are of great interest for drug design. In this paper, two piperazine-based compounds were synthesized for the first time, with different strategie...As important constitutes in many drugs, piperazine comprised compounds are of great interest for drug design. In this paper, two piperazine-based compounds were synthesized for the first time, with different strategies exploited. For one compound, a highly reactive intermediate of isothiocyanate was constructed to get the desired piperazinecarbothioamide. The synthesis of the other compound was completed sequentially through Friedel-Crafts acylation, coupling reaction and Michael addition. Both synthetic routes have short steps and acceptable yields, and such strategies can be applied to the synthesis of similar oioerazine-containin~ comoounds.展开更多
4-Acylated or 3,4-diacylated caffeic acid phenethyl ester （CAPE） was prepared as prodrug to improve its stability and lipid solubility. Their neuroprotective activities were assessed by H202 model and 6-OHDA model. ...4-Acylated or 3,4-diacylated caffeic acid phenethyl ester （CAPE） was prepared as prodrug to improve its stability and lipid solubility. Their neuroprotective activities were assessed by H202 model and 6-OHDA model. The results showed that target compounds displayed positive abilities to protect PC 12 nerve cells from oxidative stress injury, superior to that of CAPE. Additionally, target compounds showed high blood-brain barrier permeability.展开更多
AIM To investigate the effects of hydrogen-rich water(HRW) treatment on prevention of ethanol(Et OH)-induced early fatty liver in mice.METHODS In vitro reduction of hydrogen peroxide by HRW was determined with a chemi...AIM To investigate the effects of hydrogen-rich water(HRW) treatment on prevention of ethanol(Et OH)-induced early fatty liver in mice.METHODS In vitro reduction of hydrogen peroxide by HRW was determined with a chemiluminescence system. Female mice were randomly divided into five groups: control,Et OH,Et OH + silymarin,Et OH + HRW and Et OH + silymarin + HRW. Each group was fed a Lieber-De Carli liquid diet containing Et OH or isocaloric maltose dextrin(control diet). Silymarin was used as a positive control to compare HRW efficacy against chronic Et OH-induced hepatotoxicity. HRW was freshly prepared and given at a dosage of 1.2 m L/mouse trice daily. Blood and liver tissue were collected after chronic-binge liquid-diet feeding for 12 wk.RESULTS The in vitro study showed that HRW directly scavenged hydrogen peroxide. The in vivo study showed that HRW increased expression of acyl ghrelin,which was correlated with food intake. HRW treatment significantly reduced Et OH-induced increases in serum alanine aminotransferase,aspartate aminotransferase,triglycerol and total cholesterol levels,hepatic lipid accumulation and inflammatory cytokines,including tumor necrosis factor-alpha(TNF-α) and interleukin(IL)-6. HRW attenuated malondialdehyde level,restored glutathione depletion and increased superoxide dismutase,glutathione peroxidase and catalase activities in the liver. Moreover,HRW reduced TNF-α and IL-6 levels but increased IL-10 and IL-22 levels.CONCLUSION HRW protects against chronic Et OH-induced liver injury,possibly by inducing acyl ghrelin to suppress the pro-inflammatory cytokines TNF-α and IL-6 and induce IL-10 and IL-22,thus activating antioxidant enzymes against oxidative stress.展开更多
Ghrelin is a 28 amino acid peptide mainly derived from the oxyntic gland of the stomach. Both acylated(AG) and unacylated(UAG) forms of ghrelin are found in the circulation. Initially, AG was considered as the only bi...Ghrelin is a 28 amino acid peptide mainly derived from the oxyntic gland of the stomach. Both acylated(AG) and unacylated(UAG) forms of ghrelin are found in the circulation. Initially, AG was considered as the only bioactive form of ghrelin. However, recent advances indicate that both AG and UAG exert distinct and common effects in organisms. Soon after its discovery, ghrelin was shown to promote appetite and adiposity in animal and human models. In response to these anabolic effects, an impressive number of elements have suggested the influence of ghrelin on the regulation of metabolic functions and the development of obesityrelated disorders. However, due to the complexity ofits biochemical nature and the physiological processes it governs, some of the effects of ghrelin are still debated in the literature. Evidence suggests that ghrelin influences glucose homeostasis through the modulation of insulin secretion and insulin receptor signaling. On the other hand, insulin was also shown to influence circulating levels of ghrelin. Here, we review the relationship between ghrelin and insulin and we describe the impact of this interaction on the modulation of glucose homeostasis.展开更多
D-Allose and its derivatives play important roles in the field of health care and food nutrition. Pure and well-defined Dallose derivatives can facilitate the elucidation of their structure-activity relationship as an...D-Allose and its derivatives play important roles in the field of health care and food nutrition. Pure and well-defined Dallose derivatives can facilitate the elucidation of their structure-activity relationship as an essential step for drug design. The LattrellDax epimerization, refers to the triflate inversion using nitrite reagent, is known as valuable method for the synthesis of rare D-allose derivatives. Here, the influence of protecting group patterns on the transformation efficiency of D-glucose derivatives into synthetically useful D-alloses and D-allosamines via the Lattrell-Dax epimerization was studied. For C3 epimerization of D-glucose derivatives bearing O2-acyl group, an anomeric configuration-dependent acyl migration from O2 to O3 was found. In addition, a neighbouring group participation effect-mediated SN1 nucleophilic substitution of the D-glucosamine bearing C2 trichloroacetamido(TCA) group in the Lattrell-Dax epimerization was dependent upon anomeric configuration. Thus, the effect of anomeric configuration on the LattrellDax epimerization of D-glucose suggests that β-D-glucosides with low steric hindrance at C2 should be better substrates for the synthesis of D-allose derivatives. Significantly, the efficient synthesis of the orthogonally protected D-allose 13 and D-allosamine 18 will serve well for further assembly of complex glycans.展开更多
The friction and wear characteristics of lauroyl glutamine, lauroyl glycine and lauroyl alanine, used as green additives in HVI 350 mineral lubricating oil, were evaluated on a four-ball tribotester. The morphologies ...The friction and wear characteristics of lauroyl glutamine, lauroyl glycine and lauroyl alanine, used as green additives in HVI 350 mineral lubricating oil, were evaluated on a four-ball tribotester. The morphologies and chemical species of the worn surfaces were analyzed by scanning electron microscope （SEM） and X-ray photoelectron spectroscope （XPS）, respectively. The test results indicated that the three fatty acyl amino acids could effectively improve the anti-wear and friction-reducing abilities of the HVI 350 mineral oil. The improvement in anti-wear and friction-reducing abilities of the mineral oil by the related amino acids was mainly ascribed to the formation of a composite boundary lubrication film due to the adsorption of amino acids on the friction surfaces.展开更多
Silica gel supported aluminium trichloride（SiO2-AlCl3） has been shown to be a mild,efficient,and chemoseiective heterogeneous Lewis acid catalyst for the acylation of aromatic compounds with acid chlorides.The catal...Silica gel supported aluminium trichloride（SiO2-AlCl3） has been shown to be a mild,efficient,and chemoseiective heterogeneous Lewis acid catalyst for the acylation of aromatic compounds with acid chlorides.The catalyst can be reused up to five times after simple washing with ether and is stable（as a bench top catalyst）.展开更多
Poly(4-vinylpyridinium tribromide) is an efficient catalyst for the conversion of various alcohols to their corresponding acetate derivatives with acetic anhydride.This method has some advantages such as mild reaction...Poly(4-vinylpyridinium tribromide) is an efficient catalyst for the conversion of various alcohols to their corresponding acetate derivatives with acetic anhydride.This method has some advantages such as mild reaction conditions,good to excellent yields,and ease of work-up.展开更多
文摘Oxiranes as well as four and five membered rings of cyclic ethers were cleaved with acyl chloride in the presence of samarium trichloride or Eu(hfe)_3 as Lewis-acid catalyst under mild conditions,the oorresponding chloroesters were obtained readily and smoothly in excellent yields.
基金support from the National Natural Science Foundation of China(Grant Nos.22371219,22193011,21971120,21933008 and 22101191)National Science&Technology Fundamental Resource Investigation Program of China(No.2018FY201200)the Fundamental Research Funds for the Central Universities.W.Z.is grateful for the financial support from the program of China Scholarship Council(No.202206240054).
文摘Comprehensive Summary Phthalides serve as core structures pervasive in a wide array of natural products and drug molecules,which display a diverse array of biological activities.We report herein a highly efficient dynamic kinetic resolution of 3-hydroxyphthalides by chiral isothioureas(ITUs)catalyzed asymmetric acylation,facilitating the effective synthesis of a variety of chiral phthalidyl esters with good yields and enantioselectivities.Notably,this reaction features mild reaction conditions,expansive substrate scope as well as good functional group compatibility.In addition,the practicality of this method is underscored by the large-scale synthesis,reduced catalyst loading experiment and the synthesis of the chiral phthalidyl ester prodrug.
文摘Indole[2,1-α]isoquinolines are an important class of bioactive molecules and show good antibacterial activity.In the present study,an efficient copper(I)-catalyzed acylation/cyclization has been developed for the construction of indolo[2,1-α]isoquinoline derivatives by utilizing 2-aryl-N-acryloyl indole and benzohydrazide as reactants in the presence of CuI as catalyst and tert-butyl hydroperoxide as oxidant.The present protocol exhibits good functional group tolerance,and a series of acylated indole[2,1-α]isoquinolines were synthesized in moderate to good yields.Radical trapping experiments indicated that the reaction may involve a radical process.
基金the financial support of the National Natural Science Foundation of China(No.22168009)。
文摘Highly toxic phosgene,diethyl chlorophosphate(DCP)and volatile acyl chlorides endanger our life and public security.To achieve facile sensing and discrimination of multiple target analytes,herein,we presented a single fluorescent probe(BDP-CHD)for high-throughput screening of phosgene,DCP and volatile acyl chlorides.The probe underwent a covalent cascade reaction with phosgene to form boron dipyrromethene(BODIPY)with bright green fluorescence.By contrast,DCP,diphosgene and acyl chlorides can covalently assembled with the probe,giving rise to strong blue fluorescence.The probe has demonstrated high-throughput detection capability,high sensitivity,fast response(within 3 s)and parts per trillion(ppt)level detection limit.Furthermore,a portable platform based on BDP-CHD was constructed,which has achieved high-throughput discrimination of 16 analytes through linear discriminant analysis(LDA).Moreover,a smartphone adaptable RGB recognition pattern was established for the quantitative detection of multi-analytes.Therefore,this portable fluorescence sensing platform can serve as a versatile tool for rapid and high-throughput detection of toxic phosgene,DCP and volatile acyl chlorides.The proposed“one for more”strategy simplifies multi-target discrimination procedures and holds great promise for various sensing applications.
文摘Polyhydroxyalkanoate(PHA),a well-known biodegradable polymer,featuresβ-lactones as its monomers,which can be selectively synthesized through ring-expansion carbonylation of epoxides using well-defined[Lewis acid]^(+)[Co(CO)_(4)]^(-)catalysts.However,the decomposition of[Co(CO)_(4)]^(-)species at temperatures exceeding 80℃presents a hurdle for the development of commercially viable processes under high-temperature reaction conditions to reduce reaction time.Drawing insights from stable{(acyl)Co(CO)n}intermediates involved in historical HCo(CO)_(4)-catalyzed hydroformylation processes,we sought to the high-temperature catalytic activity of epoxide ring-expansion carbonylation.The developed catalyst system,[(acetyl)Co(CO)_(2)dppp]and[(TPP)CrCl],exhibited exceptional catalytic performance with an unprecedented initial turnover frequency of 4700 h^(-1)at 100℃and a turnover numbers of 93000.Notably,the catalyst displayed outstanding stability,operating at 80℃for 168 h while selectively generatingβ-lactones.
基金the National Key Research and Development Program of China(No.2021YFA1500100)the National Natural Science Foundation of China(Nos.92156017 and 21890722)+1 种基金“Frontiers Science Center for New Organic Matter”,Nankai University(No.63181206)Haihe Laboratory of Sustainable Chemical Transformation of Tianjin(No.24HHWCSS00019)for generous financial support。
文摘Mechanistic studies of the cleavage and transformation of unactivated C_(sp3)-H bonds are a significant field of chemistry.Overcoming the inherent low acidity of C-H bonds to activate the inert substrates is challenge under mild conditions.And their complex multi-step transformations may also hinder mechanistic understanding.Herein,we perform theoretical calculations and experimental studies to explore the C_(sp3)-H bonds activation and acylation mechanisms of toluene/thioether using the relatively weak base LDA.A synergistic"main and auxiliary"model was revealed involving dual lithium metal by LDA dimers,and the aryl dilithium species as an intermediate base can facilitate C_(sp3)-H activation.This model not only aids in understanding the acidity of unactivated C_(sp3)-H bonds and the nucleophilicity of their conjugate bases for their kinetic control through cooperative interactions,but also predicts unusual kinetic isotope effects(KIE)for newly designed 2-(methylthio)naphthalene that are experimentally validated.This research is expected to provide a crucial scenario for the cleavage and transformation of unactivated C_(sp3)-H bonds and the development of new functionalities for alkali metal reagents.
文摘The regioselective acylation of unprotected phenylethyl glucoside withcinnamoyl chloride leads to 6-OH cin-namoylated glucoside. In this manner, thirteen phenylpropanoidglycoside analogs were designed and prepared. Their structure was confirmed by ~1H NMR and ^(13)CNMR spectra.
文摘Several phenylselenyl esters were selected as precursors of acyl radicals and synthesised by our established method. Treatment of these phenylselenyl esters with tributyltinhydride and AIBN generated the corresponding acyl radicals, which were found to proceed in 5 exo trig or 6 endo trig cyclisations to afford high yields of cyclopentanones and cyclohexanones, The substitution groups on the substrates have played an important role on the regioselectivity of cyclisations.
基金supported by the National Natural Science Foundation of China(21336002,21222606,21376096)the Key Program of Guangdong Natural Science Foundation(S2013020013049)+1 种基金the Fundamental Research Funds for the Chinese Universities(2015PT002,2015ZP009)the Program of State Key Laboratory of Pulp and Paper Engineering(2015C04)~~
文摘A support made of mussel-inspired polydopamine-coated magnetic iron oxide nanoparticles （PD-MNPs） was prepared and characterized. The widely used Aspetyillus niger lipase （ANL） was immobilized on the PD-MNPs （ANL@PD-MNPs） with a protein loading of 138 mg/g and an activity recovery of 83.6% under optimized conditions. For the immobilization, the pH and immobilization time were investigated. The pH and thermal and storage stability of the ANL@PD-MNPs significant- ly surpassed those of free ANL. The ANL@PD-MNPs had better solvent tolerance than free ANL. The secondary structure of free ANL and ANL@PD-MNPs was analyzed by infrared spectroscopy, A kinetic study demonstrated that the ANL@PD-MNPs had enhanced enzyme-substrate affinity and high catalytic efficiency. The ANL@PD-MNPs was applied as a biocatalyst for the regioselective acylation of dihydromyricetin （DMY） in DMSO and gave a conversion of 79.3%, which was higher than that of previous reports. The ANL@PD-MNPs retained over 55% of its initial activity after 10 cycles of reuse. The ANL@PD-MNPs were readily separated from the reaction system by a magnet. The PD-MNPs is an excellent support for ANL and the resulting ANL@PD-MNPs displayed good potential for the efficient synthesis of dihydromyricetin-3-acetate by enzymatic regioselective acylation.
基金the National Basic Research Program of China(973 Program,Grant No.2012CB822100)the National Key Technology R&D Program"New Drug Innovation"of China(Grant No.2012ZX09502001-001)the National Natural Science Foundation of China(Grant No.21232002,21072016 and 21072017)
文摘By analyzing the key steps that restricted the industrial synthesis of salidroside, selective protection of tyrosol with different acylation reagents was adopted. The strategy facilitated the crystallization of intermediates, which allowed the scalable synthesis of salidroside. It included a reaction of penta-O-acetyl-β-D-glucose with acyl protected tyrosol in the presence of Lewis acid catalyst（ZnCl2）, followed by deacylation under basic condition（NaOMe/MeOH） to give the salidroside. The total yield of this three-step reaction was 47%. Final product and intermediates were purified by recrystallization, which significantly reduced the cost and made the large scale synthesis feasible.
基金National Basic Research Program of China(Grant No.2012CB518000)the National Natural Science Foundation of China(Grant No.21172012)the Specialized Research Fund for the Doctoral Program of Higher Education of China(Grant No.20120001110010)
文摘As important constitutes in many drugs, piperazine comprised compounds are of great interest for drug design. In this paper, two piperazine-based compounds were synthesized for the first time, with different strategies exploited. For one compound, a highly reactive intermediate of isothiocyanate was constructed to get the desired piperazinecarbothioamide. The synthesis of the other compound was completed sequentially through Friedel-Crafts acylation, coupling reaction and Michael addition. Both synthetic routes have short steps and acceptable yields, and such strategies can be applied to the synthesis of similar oioerazine-containin~ comoounds.
基金National Natural Science Foundation of China(Grant No.201310061931.8)
文摘4-Acylated or 3,4-diacylated caffeic acid phenethyl ester （CAPE） was prepared as prodrug to improve its stability and lipid solubility. Their neuroprotective activities were assessed by H202 model and 6-OHDA model. The results showed that target compounds displayed positive abilities to protect PC 12 nerve cells from oxidative stress injury, superior to that of CAPE. Additionally, target compounds showed high blood-brain barrier permeability.
基金Supported by a grant from the Chung Shan Medical University,No.CSMU0150011
文摘AIM To investigate the effects of hydrogen-rich water(HRW) treatment on prevention of ethanol(Et OH)-induced early fatty liver in mice.METHODS In vitro reduction of hydrogen peroxide by HRW was determined with a chemiluminescence system. Female mice were randomly divided into five groups: control,Et OH,Et OH + silymarin,Et OH + HRW and Et OH + silymarin + HRW. Each group was fed a Lieber-De Carli liquid diet containing Et OH or isocaloric maltose dextrin(control diet). Silymarin was used as a positive control to compare HRW efficacy against chronic Et OH-induced hepatotoxicity. HRW was freshly prepared and given at a dosage of 1.2 m L/mouse trice daily. Blood and liver tissue were collected after chronic-binge liquid-diet feeding for 12 wk.RESULTS The in vitro study showed that HRW directly scavenged hydrogen peroxide. The in vivo study showed that HRW increased expression of acyl ghrelin,which was correlated with food intake. HRW treatment significantly reduced Et OH-induced increases in serum alanine aminotransferase,aspartate aminotransferase,triglycerol and total cholesterol levels,hepatic lipid accumulation and inflammatory cytokines,including tumor necrosis factor-alpha(TNF-α) and interleukin(IL)-6. HRW attenuated malondialdehyde level,restored glutathione depletion and increased superoxide dismutase,glutathione peroxidase and catalase activities in the liver. Moreover,HRW reduced TNF-α and IL-6 levels but increased IL-10 and IL-22 levels.CONCLUSION HRW protects against chronic Et OH-induced liver injury,possibly by inducing acyl ghrelin to suppress the pro-inflammatory cytokines TNF-α and IL-6 and induce IL-10 and IL-22,thus activating antioxidant enzymes against oxidative stress.
基金Supported by Fonds de Recherche du Québec en Santé(toLaplante M and St-Pierre DH)Operating grants from NaturalSciences and Engineering Research Council of Canada and Diabète QuébecLaplante M also holds operating grants from the Canadian Institutes of Health Research,Canadian Liver Foundation and the Fondation de l’Institut Universitaire de Cardiologieet de Pneumologie de Québec
文摘Ghrelin is a 28 amino acid peptide mainly derived from the oxyntic gland of the stomach. Both acylated(AG) and unacylated(UAG) forms of ghrelin are found in the circulation. Initially, AG was considered as the only bioactive form of ghrelin. However, recent advances indicate that both AG and UAG exert distinct and common effects in organisms. Soon after its discovery, ghrelin was shown to promote appetite and adiposity in animal and human models. In response to these anabolic effects, an impressive number of elements have suggested the influence of ghrelin on the regulation of metabolic functions and the development of obesityrelated disorders. However, due to the complexity ofits biochemical nature and the physiological processes it governs, some of the effects of ghrelin are still debated in the literature. Evidence suggests that ghrelin influences glucose homeostasis through the modulation of insulin secretion and insulin receptor signaling. On the other hand, insulin was also shown to influence circulating levels of ghrelin. Here, we review the relationship between ghrelin and insulin and we describe the impact of this interaction on the modulation of glucose homeostasis.
基金the National Natural Science Foundation of China(Nos.21877052 and 21907039)the Natural Science Foundation of Jiangsu Province(Nos.BK20180030and BK20190575)+1 种基金the National First-class Discipline Program of Light Industry Technology and Engineering(No.LITE2018-14)the 111 Project(No.111-2-06)。
文摘D-Allose and its derivatives play important roles in the field of health care and food nutrition. Pure and well-defined Dallose derivatives can facilitate the elucidation of their structure-activity relationship as an essential step for drug design. The LattrellDax epimerization, refers to the triflate inversion using nitrite reagent, is known as valuable method for the synthesis of rare D-allose derivatives. Here, the influence of protecting group patterns on the transformation efficiency of D-glucose derivatives into synthetically useful D-alloses and D-allosamines via the Lattrell-Dax epimerization was studied. For C3 epimerization of D-glucose derivatives bearing O2-acyl group, an anomeric configuration-dependent acyl migration from O2 to O3 was found. In addition, a neighbouring group participation effect-mediated SN1 nucleophilic substitution of the D-glucosamine bearing C2 trichloroacetamido(TCA) group in the Lattrell-Dax epimerization was dependent upon anomeric configuration. Thus, the effect of anomeric configuration on the LattrellDax epimerization of D-glucose suggests that β-D-glucosides with low steric hindrance at C2 should be better substrates for the synthesis of D-allose derivatives. Significantly, the efficient synthesis of the orthogonally protected D-allose 13 and D-allosamine 18 will serve well for further assembly of complex glycans.
基金the financial support from National Natural Science Foundation of China(project No.50975282)Chongqing Science Foundation for Outstanding Youth(project No. CSTC2008,BA4037)
文摘The friction and wear characteristics of lauroyl glutamine, lauroyl glycine and lauroyl alanine, used as green additives in HVI 350 mineral lubricating oil, were evaluated on a four-ball tribotester. The morphologies and chemical species of the worn surfaces were analyzed by scanning electron microscope （SEM） and X-ray photoelectron spectroscope （XPS）, respectively. The test results indicated that the three fatty acyl amino acids could effectively improve the anti-wear and friction-reducing abilities of the HVI 350 mineral oil. The improvement in anti-wear and friction-reducing abilities of the mineral oil by the related amino acids was mainly ascribed to the formation of a composite boundary lubrication film due to the adsorption of amino acids on the friction surfaces.
文摘Silica gel supported aluminium trichloride（SiO2-AlCl3） has been shown to be a mild,efficient,and chemoseiective heterogeneous Lewis acid catalyst for the acylation of aromatic compounds with acid chlorides.The catalyst can be reused up to five times after simple washing with ether and is stable（as a bench top catalyst）.
基金supported by the Research Facilities of Ilam University,Iran
文摘Poly(4-vinylpyridinium tribromide) is an efficient catalyst for the conversion of various alcohols to their corresponding acetate derivatives with acetic anhydride.This method has some advantages such as mild reaction conditions,good to excellent yields,and ease of work-up.
