A facile and efficient method for the preparation of 2-non-substituted quinoline-4-carboxylic acids is described via the Pfitzinger reaction of isatins with sodium pyruvate following consequent decarboxylation under m...A facile and efficient method for the preparation of 2-non-substituted quinoline-4-carboxylic acids is described via the Pfitzinger reaction of isatins with sodium pyruvate following consequent decarboxylation under microwave irradiation.展开更多
Proceeding from natural amino acid L-asparagine and commercially available aldehydes a stereoselective synthesis was developed of (2S,4S)-2-alkyl(aryl)-3-(3-sulfanylpropanoyl)-6-oxohexahy- dropyrimidine-4-carboxylic a...Proceeding from natural amino acid L-asparagine and commercially available aldehydes a stereoselective synthesis was developed of (2S,4S)-2-alkyl(aryl)-3-(3-sulfanylpropanoyl)-6-oxohexahy- dropyrimidine-4-carboxylic acids, potential antihypertensive drugs, inhibitors of the angiotensin converting enzyme.展开更多
In order to understand the chemical-biological interactions governing their activities toward neuraminidase （NA）, QSAR models of 28 thiazolidine-4-carboxylic acid derivatives with inhibitory influenza A virus were d...In order to understand the chemical-biological interactions governing their activities toward neuraminidase （NA）, QSAR models of 28 thiazolidine-4-carboxylic acid derivatives with inhibitory influenza A virus were developed. The obtained HQSAR （hologram quantitative structure activity relationship）, Topomer CoMFA and CoMSIA （comparative molecular similarity indices analysis） models were robust and had good exterior predictive capabilities. Moreover, QSAR modeling results elucidated that hydrogen bonds highly contributed to the inhibitory activity, then electrostatic and hydrophobic factors. Squared multiple correlation coefficients （R2） of HQSAR, Topomer CoMFA and CoMSIA models were 0.994, 0.978 and 0.996, respectively. Squared cross-validated correlation coefficients （Q2） of HQSAR, Topomer CoMFA and CoMSIA models were in turn 0.951, 919 and 0.820. Furthermore, squared multiple correlation coefficients for the test set （R2test） of HQSAR, CoMFA and CoMSIA models were 0.879, 0.912 and 0.953, respectively. Squared cross-validated correlation coefficients for the test set （Q2ext） of HQSAR, Topomer CoMFA and CoMSIA models were 0.867, 0.884 and 0.899, correspondingly.展开更多
An adsorbent calix[4]arene carboxylic acid was employed as the adsorption material for on-line flow in jection（FI） micro-column preconcentration coupled with flame atomic absorption spectrometry（FAAS） determinatio...An adsorbent calix[4]arene carboxylic acid was employed as the adsorption material for on-line flow in jection（FI） micro-column preconcentration coupled with flame atomic absorption spectrometry（FAAS） determination of trace heavy metals（Cu, Pb, Co, Ni and Cd）. Parameters such as the pH, loading time and flow rate of sample, and the concentration, volume and flow rate of eluent were optimized. The enrichment factors are 50.0, 56.5, 11.6, 12.1 and 19.1 for Cu, Pb, Co, Ni, and Cd, respectively, and a sample throughput of 20 h–1 was obtained. The limits of de tection for Cu, Pb, Co, Ni, and Cd were in a range of 1.56―3.91 μg/L, and the relative standard deviations（RSDs） were less than 2.76%（n=7）. Furthermore, the proposed method was successfully applied to the determination of Cu, Pb, Co, Ni, and Cd in certified reference materials and various water samples.展开更多
The title compound 4-（4,6-dimethoxylpyrimidin-2-yl）-3-thiourea carboxylic acid methyl ester was synthesized by the reaction of 2-amino-4,6-dimethoxyl pyrimidine, potassium thiocyanate and methyl chloroformate in eth...The title compound 4-（4,6-dimethoxylpyrimidin-2-yl）-3-thiourea carboxylic acid methyl ester was synthesized by the reaction of 2-amino-4,6-dimethoxyl pyrimidine, potassium thiocyanate and methyl chloroformate in ethyl acetate. Single crystals suitable for X-ray measurement were obtained by recrystallization with the solvent of dimethyl formamide at the room temperature. The structure was characterized by elemental analysis and IR and determined by X-ray diffraction analysis＇ Crystallographic data： C9H12N4O4S, Mr = 272.29, monoclinic, space group C2/m with a = 1.6672（3）, b = 0.66383（12）, c = 1.1617（2） nm, β = 109.275（2）°, V = 1.2136（4） nm^3, Dc = 1.490 g/cm^3,μ = 0.281 mm^-1, F（000） = 568, Z = 4, R1 = 0.0341and wR2 = 0.1042.展开更多
AIM: To demonstrate the potential of using 2-aminothiazoline-4-carboxylic acid(ATCA) as a novel biomarker/forensic biomarker for cyanide poisoning. METHODS: A sensitive method was developed and employed for the identi...AIM: To demonstrate the potential of using 2-aminothiazoline-4-carboxylic acid(ATCA) as a novel biomarker/forensic biomarker for cyanide poisoning. METHODS: A sensitive method was developed and employed for the identification and quantification of ATCA in biological samples, where the sample extraction and clean up were achieved by solid phase extraction(SPE). After optimization of SPE procedures, ATCA was analyzed by high performance liquid chromatographytandem mass spectrometry. ATCA levels following the administration of different doses of potassium cyanide(KCN) to mice were measured and compared to endogenous ATCA levels in order to study the significance of using ATCA as a biomarker for cyanide poisoning.RESULTS: A custom made analytical method was established for a new(mice) model when animals were exposed to increasing KCN doses. The application of this method provided important new information on ATCA as a potential cyanide biomarker. ATCA concentration in mice plasma samples were increased from 189 ± 28 ng/mL(n = 3) to 413 ± 66 ng/mL(n = 3) following a 10 mg/kg body weight dose of KCN introduced subcutaneously. The sensitivity of this analytical method proved to be a tool for measuring endogenous level of ATCA in mice organs as follows: 1.2 ± 0.1 μg/g for kidney samples, 1.6 ± 0.1 μg/g for brain samples, 1.8 ± 0.2 μg/g for lung samples, 2.9 ± 0.1 μg/g for heart samples, and 3.6 ± 0.9 μg/g for liver samples. CONCLUSION: This finding suggests that ATCA has the potential to serve as a plasma biomarker / forensic biomarker for cyanide poisoning.展开更多
Highly efficient syntheses of novel fluorine bearing quinoline-4-carboxylic acids and the related compounds had been achieved from cyclocondensation of 2-amino-5-fluorophenyl glyoxylic acid 1 with benzoyle asetanilide...Highly efficient syntheses of novel fluorine bearing quinoline-4-carboxylic acids and the related compounds had been achieved from cyclocondensation of 2-amino-5-fluorophenyl glyoxylic acid 1 with benzoyle asetanilides 2 in boiling DMF, to give the target 3. Decarboxylation of 3 produced 6-fluoro-2-phenyl-3-(substituted amino)-keto-quinolines 4, while that reaction underwent refluxing, afforded 7-fluoro-1-(aryl)-3-phenyl-pyrrolo[3,4-c] quinoline-2,9-diones 5. Structure of the products has been established from their elemental and spectral analysis. All targets exhibited a high to moderate activity against some Aspergillus fungi as amylolytic agents.展开更多
4-（4,6-Dimethoxyl-pyrimidin-2-yl）-3-thiourea carboxylic acid ethyl ester was synthesized by the reaction of 2-amino-4,6-dimethoxyl pyrimidine, potassium thiocyanate and methyl chloroformate in ethyl acetate. Single ...4-（4,6-Dimethoxyl-pyrimidin-2-yl）-3-thiourea carboxylic acid ethyl ester was synthesized by the reaction of 2-amino-4,6-dimethoxyl pyrimidine, potassium thiocyanate and methyl chloroformate in ethyl acetate. Single crystals suitable for X-ray measurement were obtained by recrystallization with the solvent of dimethyl formamide at room temperature. The crystal structure was determined by X-ray diffraction analysis. Crystallographic data： C10H14N4O4S, M, = 286.31, monoclinic, space group C2/c with a = 2.5309（3）, b = 0.67682（6）, c = 1.74237（19） nm, β = 114.744（3）°, V= 2.7106（5） nm3, Dc = 1.403 g/cm3, p = 0.225 mm-1, F（000） = 1200, Z= 8, R= 0.0514 and wR= 0.1529.展开更多
Chiral 4-[(2-isopropyl-5-methylcyclohexyl)oxo]-4-oxobutanoic acid reacts with substituted anilines to produce amides 1-6 in high yields. Resulted amides 1-6 were investigated for their antifungal and antibacterial act...Chiral 4-[(2-isopropyl-5-methylcyclohexyl)oxo]-4-oxobutanoic acid reacts with substituted anilines to produce amides 1-6 in high yields. Resulted amides 1-6 were investigated for their antifungal and antibacterial activities. Compounds 2 (96.5%) against Aspergillus fumigatus and 6 (93.7%) against Helminthosporium sativum demonstrated excellent activities. However, compounds 3 (37.6%) against Bacillus subtilis, 4 (33.2%) against Pseudomonas aurignosa, 5 against Klebsiella pneumonia demonstrated excellent growth inhibition potential.展开更多
A series of esters of R-tetrahydrothiazo-2-thione-4-carboxylic acid [ R-TTCA ] was synthesized by direct esterifica- tion of R-TTCA with alcohols（CH3OH, C2H5OH, n-C3HTOH, i-C3HTOH, n-C4H9OH, sec-C4H9OH） in the prese...A series of esters of R-tetrahydrothiazo-2-thione-4-carboxylic acid [ R-TTCA ] was synthesized by direct esterifica- tion of R-TTCA with alcohols（CH3OH, C2H5OH, n-C3HTOH, i-C3HTOH, n-C4H9OH, sec-C4H9OH） in the presence of TiCl4 as the catalyst at room temperature without using any other solvent or dehydrant in high yields, 91.6%-99.1% for primary alcohols and 55%- 80% for secondary alcohols. The catalyst has a strong chemoselec-tive activity for the esterification of primary alcohols with R-TTCA in the presence of secondary alcohols. Owing to high yield, high chemoselectivity, and mild conditions used, this is an efficient method for the esterification of prima-ry alcohols with R-TTCA.展开更多
A 3D coordination polymer [Zn2（hqc）2（H2O）]n has been obtained from the reaction of 4-hydroxyquinoline-2-carboxylic acid （H2hqc） with zinc（II） salt under hydrothermal condition, and characterized by elemental a...A 3D coordination polymer [Zn2（hqc）2（H2O）]n has been obtained from the reaction of 4-hydroxyquinoline-2-carboxylic acid （H2hqc） with zinc（II） salt under hydrothermal condition, and characterized by elemental analysis, IR, TGA, PXRD and X-ray single-crystal diffraction. The complex crystallizes in the monoclinic system, space group P21/c with a = 14.305（2）, b = 9.132（2）, c = 15.356（2）, β = 103.586（7）o, V = 1949.9（4）3, Z = 4, Dc = 1.782 g/cm3, μ = 2.508 mm-1, Mr = 523.06, F（000） = 1048, T = 293（2） K, λ（MoKα） = 0.71073, S = 1.008, the final R = 0.0329 and wR = 0.0745 for 3849 observed reflections （I 〉 2σ（I））. The title complex features a 3D framework via Zn（2） linking the 1D {Zn1（hqc）2}n chains. Thermogravimetric analysis shows that its framework is highly thermally stable up to 556 ℃ in the solid state.展开更多
Chiral nitrogen-containing calix[4]arene was easily synthesized by the reaction of 25,27-di（2-bromoethoxy）- 26,28-dihydroxy-5,11,17,23-tetrakis（t-butyl）calix[4]arene with S-（-）-1-phenylethylamine in excellent yi...Chiral nitrogen-containing calix[4]arene was easily synthesized by the reaction of 25,27-di（2-bromoethoxy）- 26,28-dihydroxy-5,11,17,23-tetrakis（t-butyl）calix[4]arene with S-（-）-1-phenylethylamine in excellent yield, and showed good ability to recognize the enantiomers of mandelic acid and 2,3-dibenzoyltartaric acid. This finding has potential application to assay and separation of enantiomers of the carboxylic acids.展开更多
基金the National Basic Research Program(No.2003CB515400),administered by the Ministry of Science and Technology of China.
文摘A facile and efficient method for the preparation of 2-non-substituted quinoline-4-carboxylic acids is described via the Pfitzinger reaction of isatins with sodium pyruvate following consequent decarboxylation under microwave irradiation.
文摘Proceeding from natural amino acid L-asparagine and commercially available aldehydes a stereoselective synthesis was developed of (2S,4S)-2-alkyl(aryl)-3-(3-sulfanylpropanoyl)-6-oxohexahy- dropyrimidine-4-carboxylic acids, potential antihypertensive drugs, inhibitors of the angiotensin converting enzyme.
基金supported by the National Natural Science Foundation of China (No. 21202110)
文摘In order to understand the chemical-biological interactions governing their activities toward neuraminidase （NA）, QSAR models of 28 thiazolidine-4-carboxylic acid derivatives with inhibitory influenza A virus were developed. The obtained HQSAR （hologram quantitative structure activity relationship）, Topomer CoMFA and CoMSIA （comparative molecular similarity indices analysis） models were robust and had good exterior predictive capabilities. Moreover, QSAR modeling results elucidated that hydrogen bonds highly contributed to the inhibitory activity, then electrostatic and hydrophobic factors. Squared multiple correlation coefficients （R2） of HQSAR, Topomer CoMFA and CoMSIA models were 0.994, 0.978 and 0.996, respectively. Squared cross-validated correlation coefficients （Q2） of HQSAR, Topomer CoMFA and CoMSIA models were in turn 0.951, 919 and 0.820. Furthermore, squared multiple correlation coefficients for the test set （R2test） of HQSAR, CoMFA and CoMSIA models were 0.879, 0.912 and 0.953, respectively. Squared cross-validated correlation coefficients for the test set （Q2ext） of HQSAR, Topomer CoMFA and CoMSIA models were 0.867, 0.884 and 0.899, correspondingly.
基金Supported by the Fund of State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemi-stry, Chinese Academy of Sciences(No.RERU2011006)
文摘An adsorbent calix[4]arene carboxylic acid was employed as the adsorption material for on-line flow in jection（FI） micro-column preconcentration coupled with flame atomic absorption spectrometry（FAAS） determination of trace heavy metals（Cu, Pb, Co, Ni and Cd）. Parameters such as the pH, loading time and flow rate of sample, and the concentration, volume and flow rate of eluent were optimized. The enrichment factors are 50.0, 56.5, 11.6, 12.1 and 19.1 for Cu, Pb, Co, Ni, and Cd, respectively, and a sample throughput of 20 h–1 was obtained. The limits of de tection for Cu, Pb, Co, Ni, and Cd were in a range of 1.56―3.91 μg/L, and the relative standard deviations（RSDs） were less than 2.76%（n=7）. Furthermore, the proposed method was successfully applied to the determination of Cu, Pb, Co, Ni, and Cd in certified reference materials and various water samples.
基金This work was supported by the National Natural Science Foundation of China (20571060) and Education Committee of Shaan Xi Province (05JK294)
文摘The title compound 4-（4,6-dimethoxylpyrimidin-2-yl）-3-thiourea carboxylic acid methyl ester was synthesized by the reaction of 2-amino-4,6-dimethoxyl pyrimidine, potassium thiocyanate and methyl chloroformate in ethyl acetate. Single crystals suitable for X-ray measurement were obtained by recrystallization with the solvent of dimethyl formamide at the room temperature. The structure was characterized by elemental analysis and IR and determined by X-ray diffraction analysis＇ Crystallographic data： C9H12N4O4S, Mr = 272.29, monoclinic, space group C2/m with a = 1.6672（3）, b = 0.66383（12）, c = 1.1617（2） nm, β = 109.275（2）°, V = 1.2136（4） nm^3, Dc = 1.490 g/cm^3,μ = 0.281 mm^-1, F（000） = 568, Z = 4, R1 = 0.0341and wR2 = 0.1042.
基金Supported by NIH:NIAID/USAMRICD Interagency Agreements(W911NF-07-D-0001)the USAMRICD under the auspices of the US Army Research Office Scientific Services Program administered by Battelle(Delivery order 0557,Contract No TCN 08284)the Robert A.Welch Foundation at Sam Houston State University,Huntsville,TX,United States
文摘AIM: To demonstrate the potential of using 2-aminothiazoline-4-carboxylic acid(ATCA) as a novel biomarker/forensic biomarker for cyanide poisoning. METHODS: A sensitive method was developed and employed for the identification and quantification of ATCA in biological samples, where the sample extraction and clean up were achieved by solid phase extraction(SPE). After optimization of SPE procedures, ATCA was analyzed by high performance liquid chromatographytandem mass spectrometry. ATCA levels following the administration of different doses of potassium cyanide(KCN) to mice were measured and compared to endogenous ATCA levels in order to study the significance of using ATCA as a biomarker for cyanide poisoning.RESULTS: A custom made analytical method was established for a new(mice) model when animals were exposed to increasing KCN doses. The application of this method provided important new information on ATCA as a potential cyanide biomarker. ATCA concentration in mice plasma samples were increased from 189 ± 28 ng/mL(n = 3) to 413 ± 66 ng/mL(n = 3) following a 10 mg/kg body weight dose of KCN introduced subcutaneously. The sensitivity of this analytical method proved to be a tool for measuring endogenous level of ATCA in mice organs as follows: 1.2 ± 0.1 μg/g for kidney samples, 1.6 ± 0.1 μg/g for brain samples, 1.8 ± 0.2 μg/g for lung samples, 2.9 ± 0.1 μg/g for heart samples, and 3.6 ± 0.9 μg/g for liver samples. CONCLUSION: This finding suggests that ATCA has the potential to serve as a plasma biomarker / forensic biomarker for cyanide poisoning.
文摘Highly efficient syntheses of novel fluorine bearing quinoline-4-carboxylic acids and the related compounds had been achieved from cyclocondensation of 2-amino-5-fluorophenyl glyoxylic acid 1 with benzoyle asetanilides 2 in boiling DMF, to give the target 3. Decarboxylation of 3 produced 6-fluoro-2-phenyl-3-(substituted amino)-keto-quinolines 4, while that reaction underwent refluxing, afforded 7-fluoro-1-(aryl)-3-phenyl-pyrrolo[3,4-c] quinoline-2,9-diones 5. Structure of the products has been established from their elemental and spectral analysis. All targets exhibited a high to moderate activity against some Aspergillus fungi as amylolytic agents.
基金supported by the National Natural Science Foundation of China (20571060)Natural Science Foundation of Shaanxi Province (2007B08)Education Committee of Shaanxi Province (05JK294)
文摘4-（4,6-Dimethoxyl-pyrimidin-2-yl）-3-thiourea carboxylic acid ethyl ester was synthesized by the reaction of 2-amino-4,6-dimethoxyl pyrimidine, potassium thiocyanate and methyl chloroformate in ethyl acetate. Single crystals suitable for X-ray measurement were obtained by recrystallization with the solvent of dimethyl formamide at room temperature. The crystal structure was determined by X-ray diffraction analysis. Crystallographic data： C10H14N4O4S, M, = 286.31, monoclinic, space group C2/c with a = 2.5309（3）, b = 0.67682（6）, c = 1.74237（19） nm, β = 114.744（3）°, V= 2.7106（5） nm3, Dc = 1.403 g/cm3, p = 0.225 mm-1, F（000） = 1200, Z= 8, R= 0.0514 and wR= 0.1529.
文摘Chiral 4-[(2-isopropyl-5-methylcyclohexyl)oxo]-4-oxobutanoic acid reacts with substituted anilines to produce amides 1-6 in high yields. Resulted amides 1-6 were investigated for their antifungal and antibacterial activities. Compounds 2 (96.5%) against Aspergillus fumigatus and 6 (93.7%) against Helminthosporium sativum demonstrated excellent activities. However, compounds 3 (37.6%) against Bacillus subtilis, 4 (33.2%) against Pseudomonas aurignosa, 5 against Klebsiella pneumonia demonstrated excellent growth inhibition potential.
文摘A series of esters of R-tetrahydrothiazo-2-thione-4-carboxylic acid [ R-TTCA ] was synthesized by direct esterifica- tion of R-TTCA with alcohols（CH3OH, C2H5OH, n-C3HTOH, i-C3HTOH, n-C4H9OH, sec-C4H9OH） in the presence of TiCl4 as the catalyst at room temperature without using any other solvent or dehydrant in high yields, 91.6%-99.1% for primary alcohols and 55%- 80% for secondary alcohols. The catalyst has a strong chemoselec-tive activity for the esterification of primary alcohols with R-TTCA in the presence of secondary alcohols. Owing to high yield, high chemoselectivity, and mild conditions used, this is an efficient method for the esterification of prima-ry alcohols with R-TTCA.
基金supported by 973 (2011CB932504)NNSFC (20971121)NSF of Fujian Province
文摘A 3D coordination polymer [Zn2（hqc）2（H2O）]n has been obtained from the reaction of 4-hydroxyquinoline-2-carboxylic acid （H2hqc） with zinc（II） salt under hydrothermal condition, and characterized by elemental analysis, IR, TGA, PXRD and X-ray single-crystal diffraction. The complex crystallizes in the monoclinic system, space group P21/c with a = 14.305（2）, b = 9.132（2）, c = 15.356（2）, β = 103.586（7）o, V = 1949.9（4）3, Z = 4, Dc = 1.782 g/cm3, μ = 2.508 mm-1, Mr = 523.06, F（000） = 1048, T = 293（2） K, λ（MoKα） = 0.71073, S = 1.008, the final R = 0.0329 and wR = 0.0745 for 3849 observed reflections （I 〉 2σ（I））. The title complex features a 3D framework via Zn（2） linking the 1D {Zn1（hqc）2}n chains. Thermogravimetric analysis shows that its framework is highly thermally stable up to 556 ℃ in the solid state.
基金Project supported by the National Natural Science Foundation of China （No. 20072007）.
文摘Chiral nitrogen-containing calix[4]arene was easily synthesized by the reaction of 25,27-di（2-bromoethoxy）- 26,28-dihydroxy-5,11,17,23-tetrakis（t-butyl）calix[4]arene with S-（-）-1-phenylethylamine in excellent yield, and showed good ability to recognize the enantiomers of mandelic acid and 2,3-dibenzoyltartaric acid. This finding has potential application to assay and separation of enantiomers of the carboxylic acids.
