Flotation behavior and adsorption mechanism of(1-hydroxy-2-methyl-2-octenyl) phosphonic acid to cassiterite

The flotation behavior and adsorption mechanism of novel（1-hydroxy-2-methyl-2-octenyl） phosphonic acid（HEPA） to cassiterite were investigated by micro-flotation tests, zeta potential measurements, FTIR determination and density functional theory（DFT） calculation. The flotation results demonstrated that HEPA exhibited superior collecting performance compared with styrene phosphonic acid（SPA）. The cassiterite recovery maintained above 90% over a wide pH range of 2-9 with 50 mg/L HEPA. The results of zeta potential measurement and FTIR detection indicated that the adsorption of HEPA onto cassiterite was mainly attributed to the chemisorption between HEPA monoanions and Sn species on mineral surfaces. The DFT calculation results demonstrated that HEPA monoanions owned higher HOMO energy and exhibited a better affinity to cassiterite than SPA, which provided very clear evidence for the stronger collecting power of HEPA presented in floatation test and zeta potential measurement.

Regeneration of 2-amino-2-methyl-1-propanol used for carbon dioxide absorption

To improve the efficiency of the carbon dioxide cycling process and to reduce the regeneration energy consumption, a sterically hindered amine of 2-amino-2-methyl-1- propranol （AMP） was investigated to determine its regeneration behavior as a CO2 absorbent. The CO2 absorption and amine regeneration characteristics were experimentally examined under various operating conditions. The regeneration efficiency increased from 86.2% to 98.3% during the temperature range of 358 to 403 K. The most suitable regeneration temperature for AMP was 383 K, in this experiment condition, and the regeneration efficiency of absorption/regeneration runs descended from 98.3% to 94.0%. A number of heat-stable salts （HSS） could cause a reduction in CO2 absorption capacity and regeneration efficiency. The results indicated that aqueous AMP was easier to regenerate with less loss of absorption capacity than other amines, such as, monoethanolamine （MEA）, diethanolamine （DEA）, diethylenetriamine （DETA）, and N-methyldiethanolamine （MDEA）.

An efficient synthesis of 2,2′-arylmethylene bis-(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) and 1,8-dioxooctahydroxanthenes using ZnO and ZnO-acetyl chloride

2,2'-Arylmethylene bis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) 4l-s produced from reaction between dimedone with various aldehydes in acetonitrile using ZnO as a catalyst;whereas in the presence of ZnO-acetyl chloride catalysts the reaction is limited to give only 1,8-dioxo-octahydroxanthenes 3a-k in very good yields.

Metal 2-Hydroxy-1-Naphthaldehyde Thiosemicarbazone (Me-HNT) Complexes-A New Kind of Biomimic Enzyme Catalyst

Metal (Me=Fe(III), Mo(VI), Mn(II), Co(II), Ni(II), Zn(II) and Cu(II)) 2-hydroxy-1-naphthaldehyde thiosemicarbazone complexes (MeHNT) were synthesized and used as mimic-enzyme catalysts to mimic the active group of horseradish peroxidase (HRP). The results showed that Fe-HNT, Mo-HNT are effective catalysts, which have similar catalytic activity as HRP. The sequence of catalytic activities of tested biomimic peroxidas is Mo-HNT > Fe-HNT > Zn-HNT > Ni-HNT > Mn-HNT. Among them, Fe-HNT is used as a mimic-enzyme catalyst in determination of ascorbic acid and glucose by coupling the catalytic reaction of glucose oxidase.

Synthesis and Structural Characterization of a Tetranuclear Copper Complex with 2-Amino-1,3-thiazole

The title tetranuclear complex,（μ4-oxo）-hexakis（μ2-chloro）-tetrakis（2-amino-1,3-thiazole-N）-tetra-copper（ii） [Cu4（μ4-O）（μ-Cl）6L4]（1,L=2-amino-1,3-thiazole） was synthesized by the reaction of CuCl2·2H2O with 2-amino-1,3-thiazole in methanol and characterized by IR spectra and X-ray diffraction.Complex 1 crystallizes in triclinic,space group P1 with a=9.7137（2）,b=10.7005（2）,c=14.6505（2）,α=83.9550（10）,β=82.0930（10）,γ=67.1640（10）°,V=1387.84（4）3,Mr=883.43,Z=2,μ=3.927 mm-1,Dc=2.1144 g/cm3,F（000）=868,R=0.0332 and wR=0.0814.The complex contains a tetrahedron of four CuII atoms coordinating to a central μ4-O atom,with the six edges of the tetrahedron bridged by six Cl atoms.The Cu-O bond distances range from 1.910（2） to 1.918（2）,Cu-Cl from 2.3501（11） to 2.5924（10）,and Cu-Cu from 3.1003（6） to 3.1663（6）.The coordination geometries of the four coppers distort from trigonal bipramid to tetragonal pyramid with different distortion factors.The free animo groups of the ligands result in a lot of N-H···Cl and N-H···N intra-and intermolecular hydrogen bonds.

Synthesis,Crystal Structure and Plant Growth Regulatory Activity of 1-(3-Amino-[1,2,4]triazol-1-yl)-3,3-dimethyl-butan-2-one

The title compound 1-（3-amino-[1,2,4]triazol-1-yl）-3,3-dimethyl-butan-2-one（3） was synthesized by Hofmann-alkylation reaction of 1-chloro-3,3-dimethyl-butan-2-one（1） and ~1H-[1,2,4]triazol-3-ylamine（2） with equal amount of K_2CO_3 as acid acceptor. The structure of compound 3 was characterized by ~1H NMR, 13 C NMR, HRMS and single-crystal X-ray diffraction. The compound crystallizes in the monoclinic system, space group P21/n with a = 5.7227（8）, b = 27.924（4）, c = 6.2282（7） ？, β = 101.892（11）°, V = 973.9（2） ？~3, Z = 4, T = 180.00（10） K, μ（MoKα） = 0.087 mm^（-1）, Dc = 1.243 g/cm^3, 3832 reflections measured（3.648≤θ≤26.022°）, 1916 unique reflections（Rint = 0.0359, Rsigma = 0.0572） used in all calculations. The final R = 0.0557（I 〉 2σ（I）） and w R = 0.1276（all data）. Bioassay showed that 3 displayed excellent activity as plant growth regulator with inducing lateral root formation and enhancing primary root elongation at 0.27 mmol/L（50 ppm） in soybeen（He Feng-50）. Good water solubility was found with 50 mg in 1 m L of water. Therefore, application of 3 in agriculture is more environmentally friendly due to cosolvent-free condition, and results in improved abiotic-stress tolerance by affecting the root growth. And furthermore, it can be used as a precursor to investigate the function of regulating plant root growth.

Synthesis,Crystal Structure,and Magnetic Property of One 3D Nickel Coordination Polymer Based on 2-Hydroxy-5-(3',5'-terephthalic acid)Pyridine and 1,4-Bis(1-imdazoly)benzene

One novel nickel coordination polymer, {[Ni（OTP）（bib）1.5（H2O）]·2H2O}n（1, H2 OTP = 2-hydroxy-5-（3＇,5＇-terephthalic acid） pyridine, bib = 1,4-bis（1-imdazoly）benzene）, has been synthesized and characterized by elemental analysis（EA）, IR, powder X-ray diffraction（PXRD）, and thermogravimetric（TG） analyses. The crystal of 1 crystallizes in monoclinic, space group P21/n with a = 12.2860（5）, b = 13.8246（6）, c = 19.0140（8） A, β = 104.3870（1）°, V = 3128.2（2） A3, Z = 4, C32H28N7 Ni O8, Mr = 697.32, Dc = 1.481 g/cm^3, F（000） = 1444 and μ（Mo Kα） = 0.684 mm-1. The final R = 0.0704 and w R = 0.1764 for 5485 observed reflections with I 2σ（I） and R = 0.1087 and wR = 0.2010 for all data. Topology analysis reveals that complex 1 is a 3D 2-fold interpenetrated {4^4·6^6}-nov net based on the 1D [Ni（OTP）]n chain and the 2D [Ni2（bib）3]n sql sheet. And the variable-temperature magnetic susceptibility measurements exhibit weak antiferromagnetic coupling interaction.

Synthesis, Crystal Structure and Antitumor Activity of 4-(tert-butyl)-5-(1H-1,2,4-triazol-1-yl)-N-(2-hydroxy-3,5-diiodinebenzyl)-thiazol-2-amine

The title compound, 4-（tert-butyl）-5-（1 H- 1,2,4-triazol- 1 -yl）-N-（2-hydroxy-3,5-diio- dinebenzyl）thiazol-2-amine, was synthesized via the reduction of 4-（tert-butyl）-5-（1H-l,2,4- triazol-l-yl）-N-benzylidene-thiazol-2-amine with NaBH4, and its crystal structure was determined by single-crystal X-ray diffraction. The compound crystallizes in monoclinic system, space group P21/c with a = 7.91944（19）, b = 10.5250（3）, c = 24.4985（6） A, Z = 4, V = 2041.66（9） A3, Mr = 599.22, Dc = 1,949 Mg/m3, S = 1.120, p = 3.203 mm-1, F（000） = 1152, the final R = 0.0283 and wR = 0.0592 for 3490 observed reflections （I 〉 2σ（I））. X-ray analysis displays that the crystal water takes part in three intermolecular hydrogen bonds of O（2）-H（2A）…O（1）, O（2）-H（2B）…N（I） and N（5）-H（5）…O（2）, and an octatomic ring R^（8） is formed via intramolecular hydrogen bond of O（I）-H（IA）…N（4）. Furthermore, the I…I contacts are involved in stabilizing the overall three-dimensional network structure. The preliminary biological test shows the title compound has good antitumor activity with the IC50 value of 26 μM against the Hela cell line.

Synthesis and Crystal Structure of Ag_2(admtrz)_2(CF_3CO_2)_2(admtrz=4-amino-3,5-dimethyl-1,2,4-triazole)

The title compound (Ag2F6O4N8C12H16, Mr = 666.07) was synthesized and its crystal structure was determined by single-crystal X-ray diffraction method. It crystallizes in orthorhombic, space group Fddd with cell parameters: a = 12.2718(1), b = 23.3229(1), c = 29.1918(1) ? V = 8355.10(8) 3, Z = 16, Dc = 2.118 g/cm3, F(000) = 5184 and m = 1.966 mm-1. The structure was solved by direct methods and refined by full-matrix least-squares methods. The final R = 0.0624 and Rw = 0.1699 for 1584 observed reflections with I ≥ 2.0s(I). The molecular structure consists of two trigonal silver atoms bridged by double triazole ligands. The distance between the two silver atoms Ag(1)…Ag(1A) is 3.475(2) ?

Highly efficient synthesis of(R)-1,3-butanediol via anti-Prelog reduction of 4-hydroxy-2-butanone with absolute stereoselectivity by a newly isolated Pichia kudriavzevii

(R)-1,3-butanediol is an important pharmaceutical intermediate, and the synthesis of(R)-1,3-butanediol using green biological methods has recently been of interest for industrial application. Here, a novel strain QC-1 that efficiently transforms 4-hydroxy-2-butanone to(R)-1,3-butanediol was isolated from soil samples. Based on morphological, physiological, and biochemical tests and 5.8 S-internal transcribed spacer sequencing, the strain was identified as Pichia kudriavzevii QC-1. The reaction conditions were optimized to 35 ℃, pH 8.0, rotation speed 200 rpm, and 6:5 mass ratio of glucose to 4-hydroxy-2-butanone. Evaluation of the effects of 4-hydroxy-2-butanone concentrations on yield and cell survival rate showed that 85.60 g·L^-1 product accumulated, with an enantiomeric excess of more than 99%, when 30 g·L^-14-hydroxy-2-butanone was added at 0, 10, and 30 h in a 3-L bioreactor. Thus, strain QC-1 showed excellent catalytic activity and stereoselectivity for the synthesis of(R)-1,3-butanediol from 4-hydroxy-2-butanone.

The new antioxidant 1-benzoyl-6-hydroxy-2,2,4-trimethyl-1,2- dihydroquinoline has a protective effect against carbon tetrachloride-induced hepatic injury in rats

Liver diseases with the central pathogenetic mechanism of oxidative stress are one of the main causes of mortality worldwide.Therefore,dihydroquinoline derivatives,which are precursors of hepatoprotectors and have antioxidant activity,are of interest.We have previously found that some compounds in this class have the ability to normalize redox homeostasis under experimental conditions.Here,we initially analyzed the hepatoprotective potential of the dihydroquinoline derivative 1-benzoyl-6-hydroxy-2,2,4-trimethyl-1,2-dihydroquinoline(BHDQ)for carbon tetrachloride(CCl4)-induced liver injury in rats.Results suggested that BHDQ normalized the alanine aminotransferase,aspartate aminotransferase,and gamma-glutamyl transpeptidase in serum.We also observed an improvement in liver tissue morphology related to BHDQ.Animals with CCl4-induced liver injuries treated with BHDQ had less oxidative stress compared to animals with CCl4-induced liver injury.BHDQ promoted activation changes in superoxide dismutase,catalase,glutathione peroxidase,glutathione reductase,and glutathione transferase on control values in animals with CCl4-induced liver injury.BHDQ also activated gene transcription in Sod1 and Gpx1 via nuclear factor erythroid 2-related factor 2 and forkhead box protein O1 factors.Therefore,the compound of concern has a hepatoprotective effect by inhibiting the development of necrotic processes in the liver tissue,through antioxidation.

Syntheses and Characterization of Two New Alkaline Earth Metal-organic Topological Frameworks with 3-Amino-1H-1,2,4-triazole-5-carboxylate

Two new alkaline earth metal coordination polymers constructed from the deriva-tive of 1,2,4-triazole are presented herein,namely,{[Sr（AmTAZAc）2（H2O）]}（1） and {[Ba（AmTAZAc）2（H2O）]}（2）（AmTAZAc = 3-amino-1H-1,2,4-triazole-5-carboxylate）,which have been synthesized by using the layering method and structurally characterized by elemental analysis,IR,and single-crystal X-ray diffraction.Complexes 1 and 2 are isostructural,and both crystallize in the orthorhombic system,space group Fdd2.X-ray structural analysis shows that 1 or 2 has an intriguing 3-D infinite network of（318.438.510） topology based on a 2-D sheet structure of（4,4） net.The result shows that noncovalent interactions play an important role in strengthening the whole structures of the compounds.

Synthesis and in vitro Anti-hepatitis B Virus Activity of Some Ethyl 5-Hydroxy-4-substituted Aminomethyl-2-sulfinylmethyl-1H-indole-3-carboxylates

A novel series of ethyl 5-hydroxy-4-substituted aminomethyl-2-sulfinylmethyl-lH-indole-3-carboxylates 8a--8j and 11e--11f was synthesized and evaluated in HepG2.2.15 cells for their anti-hepatitits B virus（HBV） activity and cytotoxicity. Among them, six compounds showed more potent inhibitory activity than lamivudine. Compound 8e exhibited the most significant anti-HBV activity with an IC50 value of 1.62 μmol/L, which was 33-times more potent than the reference drug lamivudine（IC50=54.78μmol/L）.

Synthesis and Biological Activity Study of New Schiff and Mannich Base Ligands Derived from Isatin and 3-Amino-1,2,4-triazole and Their Metal Complexes

Two new Mannich and Schiff base ligands namely： （1-（3＇-amino-methyl-1＇（H）-1＇,2＇,4＇-triazole）-3-（1＇（H）-l＇,2＇,4＇- triazole-3＇-yl） iminoisatin （Lt） and l-morpholinomethyl-3-（1＇（H）-1＇,2＇,4＇-triazolyl）iminoisatin （LII） were prepared from condensation reaction of the new Schiff base 3-（l＇（H）-l＇,2＇,4＇-triazole-3＇-yl）iminoisatin （SBH） （0.01 mol） with formaldehyde and 3-amino-l,2,4-triazole （3-At） or with formaldehyde and morpholine （0.01 mole each） respectively. Structures were characterized by tH NMR, CHN analyses, mass spectra and IR spectra. Metal complexes were synthesized by heating each ligand （0.02 mo with metal salts （0.01 moo in ethanol or ethanol： acetone mixture respectively. The formula of metal complexes were suggested depending on CHN and thermal analyses, metal and chloride contents, IR and UV-visible spectra, magnetic moments （laefr） and conductivity measurements. All complexes were of octahedral geometry except palladium （II） complexes which were square planar. The two ligands and some selected metal complexes showed various antibacterial and cytotoxic effects.

Syntheses, Characterization and Biological Activity of Coordination Compounds of 3-Hydroxy-2-methyl-4<i>H</i>-pyran-4-one and Its Mixed Ligand Complexes with 1,2-Diaminocyclohexane

Coordination compounds of 3-hydroxy-2-methyl-4H-pyran-4-one with iron(III), cobat(III) and chromium(III) were synthesized with M:L (1:2). Mixed ligand coordination compounds of 3-hydroxy-2-methyl-4H-pyran-4-one and 1,2-diaminocyclohexane using the same metal ions were also synthesized M:L1:L2 (1:1:1) where L1 is 3-hydroxy-2-methyl-4H-pyran-4-one and L2 is 1,2-diaminocyclohexane. The coordination compounds obtained were characterized using electronic and infrared spectral analyses, magnetic susceptibility and percentage metal analysis. They were also evaluated for their cytotoxic and antioxidant activities. The result obtained suggested that octahedral geometry was obtained for all the compounds, as a result of additional two molecules of the solvent coordinated to the metal ions. Both the primary and secondary ligands coordinated in a bidentate fashion. The synthesized compounds exhibited moderate cytotoxicity, although none was as active as the standard. The cobalt(III) mixed ligand complex elicited the highest activity. The synthesized compounds all exhibited good to moderate antioxidant activity.

Synthesis and Crystal Structure of Tri(4-(3-hydroxy2-ethyl-4-pyridinone-1-yl)-aniline Condensation Salicylaldehydato) Monohydratotricopper(II)Dimethylformamide Monohydrate Solvate

The title complex [Cu3L3(H2O)]DMFH2O (H2L = 4-(3-hydroxy-2-ethyl-4- pyridinone-1-yl)-aniline condensation salicylaldehyde) was obtained. The single-crystal X-ray study shows that it is a trinuclear compound [Cu3(C20H15N2O3)3(H2O)]DMFH2O. The coordi- nation sphere about each copper ion in the complex consists of two oxygen atoms from hydroxylpyridinone moiety of one ligand and one oxygen and one nitrogen atoms from salicyladehyde Schiff-base moiety of another ligand arranged in a slightly distorted square planar geometry. Among the three copper ions, one (Cu(2)) is coordinated by the other oxygen atom of water molecule on the fifth coordinate position to form a distorted square pyramid geometry. The crystal is of monoclinic, space group P21/c with a = 12.9202(5), b = 27.197(1), c = 17.0116(7) ? b = 100.588(1), V = 5875.9(4) 3, Z = 4, C63H57N7O12Cu3, Mr = 1294.78, Dc = 1.464 g/cm3, m = 1.146 mm-1, F(000) = 2668, R = 0.0784 and wR = 0.1546 for 6926 observed reflections with I > 2s(I). The differences of coordinate bond lengths are observed between anhydrous and hydrous units: in the former unit, the average bond lengths are 1.978 ?for CuN (azomethine), 1.883 ?for CuO (phenolic) in Schiff-base moiety, 1.959 ?for CuO (keto), and 1.919 ?for CuO (hydroxy) in hydroxypyridinone moiety; while those in the latter are longer with the following corresponding values: 1.985(5), 1.908(5), 1.993(5) and 1.919(4) ? respectively. The Cu(2)O (water) bond length is 2.375(6) ?

Synthesis of 2-(N-formyl)-5-aryl/aryloxymethyl-1,3,4-thiadiazoles with potential bioactivity in PEG-400

An environmental benign procedure for synthesis of 2-(N-formyl)-5-aryl/aryloxymethyl-1,3,4-thiadiazoles has been developed by reaction of 2-amino-5-aryl/aryloxymethyl-1,3,4-thiadiazoles with formic acid in PEG-400.The key advantages of this protocol are the shorter reaction time,higher yields,lower cost,simple workup,and environment-friendly compared to conventional organic solvent reaction.The present method does not involve any hazardous organic solvent or catalyst.

Use of Ultrasound and Microwave Irradiation for Clean and Efficient Synthesis of 3,3’-(Arylmethylene)bis (2-hydroxynaphthalene-1,4-dione) Derivatives

Nine 3,3’-(arylmethylene)bis(2-hydroxynaphthalene-1,4-dione) derivatives were synthesized through the reaction between 2-hydroxy-1,4-naphthalen-1,4-dione and different aromatic alde-hydes in water applying ultrasonic irradiation for 5 min at room temperature and microwave irradiation for 15 min at 70°;C. Two of the nine derivatives, compounds 3-e and 3-i, obtained from 3-bromo-hydroxybenzaldehyde and 5-methylfuran-2-carbaldehyde, respectively, are previously unpublished. The structures of all compounds were established on the basis of their spectral data and mass analysis. The attractive features of this synthesis protocol include mild conditions, high atom-economy and excellent yields with the elimination of water as the only by-product.

An improved synthesis of (-)-7-isopropyl-cis-l-amino-2-indanol the chiral auxiliary for 6π-azaelectrocyclization

（-）-7-Isopropyl-cis-l-amino-2-indanol, a key chiral auxiliary and ligand in the highly stereo-selective asymmetric 6π- azaelectrocyclization, has been prepared previously by two methods. Each however involved using of one extreme condition, i.e. high temperature or high pressure, for the respective reaction. A modified reaction route employed mild condition for synthesis was presented in this report.

Synthesis, Crystal Structure, Antibacterial Activities and Theoretical Computation of 3-(2-Hydroxybenzly)-4-(4-isopropylbenzyl- ideneamino)-(1H)-1,2,4-triazole-5-thione

The title compound C18H18N4OS has been synthesized by the reaction of 3-（2-hydroxy- benzyl）-4-amino-（1H）-1,2,4-triazole-5-thione with 4-isopropylbenzaldehyde in ethanol and characterized by IR, ^1H NMR spectra and elemental analysis. Its structure was determined by X-ray diffraction analysis. The crystal belongs to monoclinic, space group P21/c with a = 11.605（2）, b = 7.401（1）, c = 20.339（2） A, β= 103.05（2）°, V= 1701.8（4） A^3, Z = 4, Mr = 338.42,μ = 0.202 mm^-1, Dc = 1.321 g/cm^3 and F（000） = 712. The structure was solved by direct methods and refined to R = 0.0428 and wR = 0.1069. Due to the intramolecular O-H…N hydrogen bond and π-π stacking interactions between the benzene （C（1）～C（6）） and triazole rings, the two planes are essentially coplanar. Their biological activities have been measured, showing this type of compound has certain antibacterial activity for Staphylococous aureus and Bacillus subtilis. Based on the quantum chemistry calculation at the RHF/6-31G level, the frontier orbitals and electrostatic potential of the title compound were also discussed.