Discovery of nitric oxide in marine ecological system and the chemical characteristics of nitric oxide

Nitric oxide was discovered in both the lab and the alga culture pond of Daya Bay (1―300 m3) before the growth of alga reached the maximum. The results included: (1) NO was detected before the growth of alga reached the maximum in the case of red tide alga and food alga, and the concentration of NO decreased rapidly after the growth maximum; (2) the curve between NO con-centration and time indicated that the concentration of NO in the daytime was more than that at night, and the maximal concentration of NO appeared in the midday (1―3 pm); (3) the growth of alga reached the maximum in the alga culture pond of Daya Bay in about 8―10 d, and NO was discovered in 5―7 d; (4) the measured NO concentration was 10-9 mol/L, 10-9―10-8 mol/L, and 10-8 mol/L for Haeterosigma akashiwo, mixed alga in Daya Bay and Chaetoceros Curvisetus individually; (5) the relation of illumination with NO production was discussed.     

An efficient and facile procedure for synthesis of octyl polyglucoside

Nonionic surfactant alkyl polyglucoside (APG) was prepared by direct glycosidation of alkyl alcohol with glucose in the presence of sulfate acid-silica gel (H_2SO_4/SiO_2) as solid acidic catalyst.The quantity of catalyst was only of 1 wt%,based on the glucose,and the conversion of glucose was close to 100% at 110℃in 1.5h.The product was characterized by FT-IR,mass and ~1H NMR spectra.The degree of polymerization (DP) of the glucose in the product was 1.37,and critical micelle concentration (CMC) of product was only 0.0104 wt%.     

1-萘甲酰苯胺和2-萘甲酰苯胺的分子内电荷转移研究

A series of 1-naphthanilides (1) and 2-naphthanilides (2) with varied substituents at the para- or meta-position of anilino phenyl ring were prepared and their absorption and fluorescence spectra in a nonpolar solvent cyclohexane were investigated. An abnormal long wavelength emission assigned to the charge transfer (CT) state was found for all of the prepared naphthanilides in cyclohexane. A linear free energy correlation between the CT emission energies and the Hammett constants of the substituent was found within series 1 and 2. The value of the linear slope with 1 (0.42 eV) was higher than that with 2 (0.32 eV) being close to that of the substituted benzanilides 3 (0.31 eV) The higher slope value suggested higher charge separation extent in the CT state of 1 than that of 2. It was found that the corresponding linear slope of anilino-substituted benzanilides remained unchanged when para-, meta-, ortho-, or ortho, ortho-methyls were introduced into the anilino moiety, which ruled out the possible contribution of the difference in the steric effect and the electron accepting ability of the naphthoyl acceptor in 1 and 2. Compared with the early reported N-substituted-benzoyl-aminonaphthalene derivatives 4 and 5, it was considered that 1-naphthoyl enhanced the charge transfer in 1 and the proximity of its ^1La and ^1Lb states was suggested to be responsible. It was shown that 1- and/or 2-substituted naphthalene cores acting as either electron acceptor (naphthoyl) or electron donor (aminonaphthalene) were different in not only electron accepting (donating) ability but also shaping the charge transfer pathway.     

Kopsia Singapurensis提取物对酸性介质中低碳钢的缓蚀效应(英文)

The influence of the alkaloid extract of Kopsia singapurensis on the corrosion behavior of mild steel (MS) in 1 mol·L-1 HCl and 1 mol·L-1 H2SO4 was studied using electrochemical techniques, viz., potentiodynamic polarization and AC impedance. The experimental results clearly show that the plant extract effectively inhibits corrosion in both acid media and the inhibition efficiency obtained from the electrochemical techniques is in good agreement. Furthermore, the polarization technique indicates that the extract acts as an anodic type inhibitor in HCl and as a mixed type in H2SO4. Scanning electron microscopy (SEM) was carried out to examine the surface morphological changes of metal specimens in both the inhibited and uninhibited solutions. SEM images show the formation of an adsorbed layer over the metal surface by the inhibitor molecule. The presence of alkaloidal constituents in the plant extract was confirmed by Fourier transform infrared (FTIR) spectroscopy and chemical analysis.     

Urea-based polyacetylenes as an optical sensor for fluoride ions

Novel acetylenes carrying urea groups, 1-(4-ethynylphenyl)-3-(4-nitrophenyl) urea (1), 1-(4-propargyl)-3-(4-nitrophenyl) urea (2), were synthesized and polymerized with rhodium catalyst. Polymers [poly(1) and poly(2)] with moderate molecular weights were obtained in good yields. The anion sensing ability of poly(1) and poly(2) was estimated using the tetra-n-butylammonium (TBA) salts of a series of anions in DMF. Upon the addition of F-, the color of the DMF solution of poly(1) and poly(2) immediately turned to a different color, while the color of solution changed slightly upon addition of Cl-, HSO4-, Br-, and NO3-, indicating the F- sensing ability of poly(1) and poly(2). The 1H-NMR titrations of poly(1) revealed that the colorimetric response of poly(1) was triggered by the urea/F- interaction through the hydrogen bonding and/or deprotonation process. The absorption spectra titration and Hill plot analysis were carried out to measure the F- binding ability, and the Hill coefficient in the poly(1)/F- complexation was found to be 5.8. This result clearly indicated that this binding mode between poly(1) and F- was based on a positive homotropic allosterism.     

硫酸溶液中1,1’-硫代羰基二咪唑在碳钢上的吸附及缓蚀影响和碘离子的增强效应

The inhibition effect of 1,1’-thiocarbonyldiimidazole (TCDI) on the corrosion behaviors of mild steel (MS) in 0.5 mol·L -1 H2SO4 solution was studied with the help of potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and linear polarization resistance (LPR) techniques. The effect of immersion time on the inhibition effect of TCDI was also investigated over 72 h. For the long-term tests, hydrogen evolution with immersion time (VH2-t) was measured in addition to the three techniques already mentioned. The thermodynamic parameters, such as adsorption equilibrium constant (Kads) and adsorption free energy (⊿Gads) values, were calculated and discussed. To clarify inhibition mechanism, the synergistic effect of iodide ion was also investigated. The potential of zero charge (PZC) of the MS was studied by electrochemical impedance spectroscopy method, and a mechanism of adsorption process was proposed. It was demonstrated that inhibition efficiency increased with the increase in TCDI concentration and synergistically increased in the presence of KI. The inhibition efficiency was discussed in terms of adsorption of inhibitor molecules on the metal surface and protective filmformation.     

Propylene Polymerization Catalyzed by Bis(R_3-indenyl) Zirconium Dichloride/Aluminoxane──Synthesis of Metallocenes and Influence ofSolvent Polarity on Polymerization

Three unbridged metallocenes, bis(2,4,7-Me3-indenyl)zirconium dichloride(1) , bis(2-Me-4, 7-Et2-indenyl)zirconium dichloride (2) and bis (2, 4, 6-Me3-indenyl) zirconium dichloride (3) were synthesized. The effect of solvent polarity on propylene polymerization catalyzed by the metallocenes in the presence of methylaluminoxane(MAO) and triisobutylaluminum(TIBA) was investigated in the toluene/CH2Cl2 mixed solvent. Changing the solvent polarity was found to influence the catalytic activity, polymer molecular weight and stereospecificity of the catalysts. The changes in the position of the substituents on the ligand caused the different responses of the catalyst to the changes in solvent polarity. The isotactic stereosequence of polypropylene was found to increase with the increase in the polarity of the reaction medium.     

PREPARATION OF POLY（METHYL METHACRYLATE）/LAYERED DOUBLE HYDROXIDES NANOCOMPOSITES via in situ SOLUTION POLYMERIZATION

An exfoliated layered double hydroxides/poly(methyl methacrylate)(LDHs/PMMA)nanocomposite was prepared by in situ solution polymerization of methyl methacrylate(MMA)in the presence of 4-vinylbenzenesulfonate intercalated LDHs(MgAl-VBS LDHs).MgAl-VBS LDHs was prepared by the ion exchange method,and the structure and composition of the MgA1-VBS LDHs were determined by X-ray diffraction(XRD),infrared spectroscopy and elemental analysis.XRD and transmission electron microscopy(TEM)were employed to examine the structure of LDHs/PMMA nanocomposite.It was indicated that the LDHs layers were well exfoliated and dispersed in the PMMA matrix.The grafting of PMMA onto LDHs was confirmed by the extraction result and the weight fraction of grafted PMMA increased as the weight fraction of LDHs in the nanocomposites increased.     

GAS PERMEABILITY OF COPOLY(1-TRIMETHYL-SILYL-1-PROPYNE-PENTAMETHYL-DISILYL-1-PROPYNE) MEMBRANE

The permeability of copoly (1-trimethylsilyl-1-propyne-pentamethyldisilyl-1-propyne) membrane for twelve gases (0_2, N_2, CO_2, H_2, D_2, He, At, CH_4, C_2H_4, C_2H_6, C_3H_6 and C_3H_8) was examined. The basic laws of solution and diffusion of the gases in the membrane were expounded preliminarily. It was found that a linear relationship between logarithm of diffusion coefficient (D) and critical molar volume (V_c) of the gases. The permeation characteristics of the gases in the copoly (1-trimethylsilyl-1-propyne-pentamethyldisilyl-1-propyne) membrane was also discussed.     

Chemical Modification of Poly(epichlorohydrin) Using Montmorillonite Clay

Cationic ring opening polymerization of epichlorohydrin (1) and acetic anhydride in the presence of Maghnite- H (Mag-H＋) as a catalyst afforded, ω-diacetylated poly(epichlorohydrin) (P1) in a moderate yield and molecular weight without formation of side products and degradation. P1 was chemically modified with morpholine (2), piperidine (3) and pyrrolidine (4) into the corresponding new functional poly(epichlorohydrin)s (P2—P4) in a moderate reaction conversion . The conversion of P1 into P2—P4 was confirmed by using FTIR and NMR spectroscopy and the yield was calculated from the elemental analysis data according to the mole fraction concept. The obtained functional polymers were further characterized by thermal analysis which showed a substantial increase of the glass transition temperature (Tg). Thus, the chemical modification of α,ω-acetylated PECH using Mag-H＋ offers a simple method for obtaining functional polymers. Mag-H＋ is a montmorillonite sheet silicate clay exchanged with proton.     

Reactions of Pinacols with One-Electron Oxidants

Oxidation of the tetraarylpinacols (Ar(2)COH)(2), 1a-e, in which Ar = C(6)H(5) (1a), 4-ClC(6)H(4) (1b), 4-MeC(6)H(4) (1c), 4-MeOC(6)H(4) (1d) and 4-Me(2)NC(6)H(4) (1e), by thianthrene cation radical (Th(*+)) in CH(3)CN and in CH(2)Cl(2) led quantitatively to the corresponding diaryl ketones Ar(2)C=O (2a-e), provided a sufficient amount of base, 2,6-di-tert-butyl-4-methylpyridine (DTBMP), was present to prevent presumed acid-catalyzed rearrangement. In the case of 1e, continued oxidation of 2e was also observed. Oxidation of 1a by (4-BrC(6)H(4))(3)N(*+)SbCl(6)(-) and (4-BrC(6)H(4))(3)N(*+)SbF(6)(-) (Ar(3)N(*+)) occurred analogously. Evidence for the catalytic, cation-radical rearrangement of 1a by Ar(3)N(*+) (reported in earlier literature) and by Th(*+) could not be found. Quantitative oxidation of 1a to 2a and of 1d to 2d was obtained also with NOBF(4), again provided that sufficient DTBMP was present to prevent acid-catalyzed rearrangement. Catalytic, oxidative rearrangement of 1d at room temperature and (as reported in earlier literature) at -5 degrees C was not observed. Oxidation was also observed of 2,3-diphenyl-2,3-butanediol (3) to acetophenone (9) and of 1,1-dimethyl-2,2-diphenylethanediol (4) to 2a and acetone by Th(*+). Oxidation of 2,3-dimethyl-2,3-butanediol (5) by Th(*+) was not observed. Instead, even in the presence of DTBMP, pinacolone (10) and tetramethyloxirane (11) were formed, through, it is proposed, a mechanism involving complexation with Th(*+).     

合成双酚AF的新方法

由六氟丙酮三水合物和苯胺,经缩合、重氮化、水解、Friedel-Crafts烷基化等4步反应在常压下合成了双酚 AF。首先,以五氧化二铌为催化剂,在 n (HFA•3H₂O) : n (aniline) : n (Nb₂O₅) = 2 : 1 : 0.1,回流 6 h 条件下,合成出中间体（Ⅰ）,收率高达96.3%。然后在重氮化温度为 ﹣2 ～ 2 ℃,硫酸质量分数为 14.7%,n (Ⅰ) : n (H₂SO₄) : n (NaNO₂) = 1 : 4.1 : 1.1,及水解时硫酸质量分数为 50%,n (H₂SO₄) : n (Ⅰ) = 11.0 : 1、108～112 ℃反应 1.5 ～ 2 h 的优化条件下,化合物Ⅰ经重氮化、水解后以 92.7%的高收率得到中间体 2-（4-羟基苯）六氟异丙醇（Ⅱ）;再在甲磺酸存在下,化合物Ⅱ与苯酚经Friedel-Crafts烷基化反应以 72.4% 的收率合成了目标产物双酚 AF（Ⅲ）,总收率为 64.6%（以苯胺为基准计算）。     

Preparation of 1-Trifluoroethyl-4-methoxy-5-chloropyridazin-6-one: Methyl Shift of 4-Methoxy-5-chloropyridazin-6-one

N1-Trifluoroethyl-4-methoxy-5-chloro-3-pyridazone (4) was synthesized by the substitution reaction of 4methoxy-5-chloro-3-pyridazone (1) with trifluoroethyl trifluoromethanesulfonate (A) at basic condition. In the most of reaction conditions, N1-methyl-4-methoxy-5-chloro-3-pyridazone (2) was obtained as a major by-product, which means that the methyl group in the 4-methoxy shifted to N-1 position inter-molecularly aided by A or trifluoroethyl methanesulfonate (B). We obtained N1-methyl-4-trifluoro-ethoxy-5-chloro-3-pyridazone (3) in the reaction of 1 with B at higher temperature in different solvents with different yield (Table 1 ), which mechanism was shown in Figure 1. When we tried to synthesize 4 in the reaction of 1 with trifluoroethyl toluenesulfonate under basic condition, 6 was obtained (Figure 2). All the detailed mechanisms are undergoing investigated.     

Regioselective alkylation of 2-alkyl-5,6,7,8-tetrahydro-3h-cycloheptimidazol-4-ones and 2-alkyl-3h-cycloheptimidazol-4-ones

Regioselective alkylation of 2-alkyl-5,6,7,8-tetrahydro-3H-cycloheptimidazol-4-one (1) and 2-alkyl-3H-cycloheptimidazol-4-one (2) was investigated. 3-[2'-(1-tert-Butyl-1H-tetrazol-5-yl)biphenyl-4-ylmethyl]-2-propyl-5,6,7,8-tetrahydro-1H-cycloheptimidazol-4-one (6) was preferentially obtained under the conditions by using NaH in DMF or THF. On the other hand, 3-[2'-(1-tert-butyl-1H-tetrazol-5-yl)biphenyl-4-ylmethyl]-2-propyl-5,6,7,8-tetrahydro-3H-cycloheptimidazol-4-one (5), the synthetic intermediate compound of Pratosartan, was obtained selectively in the presence of n-Bu(4)NBr in toluene by using aqueous sodium hydroxide as a base. In this reaction, it was found that the concentration of the alkaline solution influences its regioselectivity. This selectivity was observed even for aldehyde and ester derivatives.     

A novel colorimetric sensor of dihydrogen-phosphate based on metal complex between 8-hydroxy quinoline-5-azo-4'-nitrobenzene and cobalt

A novel colorimetric sensor based on 8-hydroxy quinoline-5-azo-4'-nitrobenzene (1) was prepared and used for recognizing anions. 1 and its metal complex (1.Co) were found to show response to anions such as CH(3)CO(2)(-), H(2)PO(4)(-), HSO(4)(-), F(-) and dramatic color changes were observed. The selectivity and sensitivity of 1 and 1.Co for sensing anions were different, which was in the order of CH(3)CO(2)(-)>F(-)>H(2)PO(4)(-)>HSO(4)(-) for 1 and H(2)PO(4)(-)>HSO(4)(-)>CH(3)CO(2)(-) approximately F(-) for 1.Co, respectively. In CH(3)CN, sensor 1.Co exhibited excellent specificity toward H(2)PO(4)(-), and the color variety was dependent on the concentration of H(2)PO(4)(-) which was attributed to anion structure and stability of anionic complex (1-anion), metal complex (1-Co) and inorganic complex (Co-anion).     

A new unusual natural pigment from Selaginella sinensis and its noticeable physicochemical properties

A new unusual pigment with a novel carbon framework named selaginellin (1) was isolated from the acetone extract of Selaginella sinensis, and its methoxy derivative (1a) was synthesized. Both selaginellin 1 and 1a are racemic compounds. The structure of selaginellin 1 was established as (R,S)-4-[(4'-hydroxy-4-(hydroxymethyl)-3-((4-hydroxyphenyl)ethynyl)biphenyl-2-yl)(4-hydroxyphenyl)methylene]-2,5-cyclohexadien-1-one and 1a as (R,S)-4-[(4'-methoxy-4-(methoxymethyl)-3-((4-methoxyphenyl)ethynyl)biphenyl-2-yl)(4-methoxyphenyl)methylene]-2,5-cyclohexadien-1-one by the analysis of one- and two-dimensional NMR data, HR-ESIMS, EI-MS, IR, UV, CD, and single-crystal X-ray experiments, and the mechanism of their color change according to different pH values and fluorescent properties was studied.     

枸杞子糖缀合物LbGp4糖链的结构及其免疫活性的研究

枸杞子糖缀合物LbGp4经β--消除、柱层析分离后得到一条分子量高达180800的分支多糖化合物LbGp4-OL.LbGp4-OL糖基组成为n(Rha):n(Ara):n(Gal)=0.05:1.33:1.根据甲基化、部分酸水解及¹HNMR、¹³CNMR分析,确定了其主要的结构,并对LbGp4和LbGp4-OL的免疫活性进行了研究.     

Reactions and polymerization of 1-trityl-4-vinylimidazole

1-Trityl-4-vinylimidazole was prepared by direct tritylation of 4(5)-vinylimidazole and polymerized using a free radical initiator. Poly(1-trityl-4-vinylimidazole) was hydrolyzed using aqueous acetic acid to give poly[4(5)-vinylimidazole]. The poly[4(5)-vinylimidazole], which was obtained from the hydrolysis of poly(1-trityl-4-vinylimidazole), was compared with poly[4(5)-vinylimidazole] prepared directly from 4(5)-vinylimidazole for differences in stereochemistry. The stereochemistry of both polymers was found to be similar by high-resolution NMR. Thus, the trityl does not influence the stereochemistry of poly[4(5)-vinylimidazole]. The reaction of 1-trityl-4-vinylimidazole with n-butyllithium gave 2-lithio-1-trityl-4-vinylimidazole. This intermediate was used to prepare 2-substituted 4(5)-vinylimidazoles, which are new monomers that can be polymerized using free radical initiators.     

9,9-二[4-(4-羧基苯氧基)苯基]呫吨的合成

在碘化亚铜、四丁基溴化铵和磷酸钾存在下,9,9-二(4-羟基苯基)呫吨(1)和4-甲基碘苯(2)于N,N-二甲基甲酰胺溶剂中发生Ullmann偶联反应,加热回流反应24 h,以95%的产率合成了中间体--9,9-二[4-(4-甲基苯氧基)苯基]呫吨(3),继而加入催化量的N-溴代丁二酰亚胺并在光照条件下,将中间体3氧化得到一种新型芳香族二羧酸--9,9-二[4-(4-羧基苯氧基)苯基]呫吨(4),其产率为84%,二步反应总收率为79.8%。 目标化合物4经1H NMR、13C NMR、IR和元素分析测试技术确定了其结构。 该法具有原料易得,操作简单,反应条件温和,收率高等优点。     

Gelation and its relevance to the function of polysaccharides

(1→4)-α- and (1→4)-β-D-linked glucosidic oligosaccharide chains were generated by the Monte Carlo method, and the scattering from the systems composed of simulated chains was calculated to compare with the results of small-angle X-ray scattering from the oligosaccharides in aqueous solution. By extending the simulation to a longer chain, a single chain conformation of (1→4)-α- and (1→4)-β-D-linked polysaccharides was evaluated. On the basis of the simulation, the suprastructure of (1→4)-α- and (1→4)-β-D-linked polysaccharides and their gel formation mechanism were discussed in some detail by analyzing the small-angle X-ray scattering from the aqueous solutions of (1→4)-α- and (1→4)-β-D-linked polysaccharides.