磷钼杂多酸光度法测定吲哚乙酸

研究了吲哚乙酸与磷钼杂多酸在浓度为 0 .0 3 mol/L的硫酸介质中发生氧化还原反应 ,形成的还原产物 (钼蓝 )在 NH3-NH4Cl缓冲溶液 (p H8.4)中最大吸收波长为 314 nm,表观摩尔吸光系数 ε值为 3.5 4× 10 4L· mol-1·cm-1 ,吲哚乙酸含量在 5 .0× 10 -7～ 5 .0× 10 -5 mol/L范围内符合比尔定律 ,检出限为 1.0× 10 -7mol/L,对 2 .0 0× 10 -5 mol/L吲哚乙酸测定 10次的相对标准偏差为 6 .42 % ,加标回收率为 94.2 %～ 10 0 .1%     

1-[2-(2,4-二氯苯氧)乙酰基]-5-氨基-1H-吡唑衍生物的合成与生物活性

为寻求高效低毒的农药,设计、合成了一系列新的1-[2-(2,4-二氯苯氧)乙酰基]-5-氨基-1H-吡唑衍生物3a～3j和4a～4d.元素分析,1H NMR,IR和MS证实了它们的结构.初步的生物活性测试结果表明,在10 mg/L浓度下,化合物3a～3j和4a～4d对油菜的根茎均有很好的抑制作用,对油菜的根的抑制率为90.0%～98.7%;于100 mg/L浓度下,对稗草的根抑制率为84.0%～100%.     

火焰原子吸收光谱法间接测定青霉素V钾

基于青霉素V钾在酸性条件下的水解产物可与Pb2 + 形成沉淀 ,用火焰原子吸收光谱法测定沉淀中铅的含量 ,可间接测定药片中青霉素V钾的含量。在优化条件下 ,测定青霉素V钾的线性范围为 5 .15× 10 -5～ 4 .12× 10 -4mol/L ,线性回归方程为A =2 .4 2× 10 3 c - 0 .0 6 3 1,相关系数为 0 .999 1,检出限为 7.392× 10 -7mol/L ,测定结果的相对标准偏差为 0 .0 6 %～ 0 .6 9% ,回收率为 97.8%～ 10 2 .0 %。     

反相高效液相色谱法测定烧伤大鼠体内的肠三叶因子

 采用反相高效液相色谱法测定烧伤大鼠体内的肠三叶因子 (ITF) ,其中色谱柱为HypersilC4柱 ( 4 6mmi.d .× 2 5 0mm ,柱填料的孔径为 3 0nm ,粒度为 5 μm) ,流动相为乙腈 水 (含体积分数为 0 1%的三氟乙酸 )溶液 ,梯度洗脱 ,流速为 1mL/min。在 2 14nm检测波长下 ,ITF在 1mg/L～ 10 0mg/L时具有良好的线性关系 ,相关系数为0 9989,最低检测限为 0 5mg/L。ITF的加标回收率为 93 95 %～ 10 5 90 % ,日内测定结果的RSD <5 3 3 % ,日间测定结果的RSD <6 10 %。方法准确、灵敏 ,可作为一种有效的分析手段。     

无保护流体室温磷光法测定1-萘胺的研究

研究了 1 -萘胺 ( NNA)的无保护流体室温磷光 ( NP- RTP)测定条件及共存物影响。在以 KI为重原子微扰剂、Na2 SO3为除氧剂及 λex/λem=31 7/5 1 8nm的最佳组合条件下 ,测定 NNA的线性范围及检出限分别为 1 .4× 1 0 - 7～ 2 .5× 1 0 - 5mol/L及1 .2× 1 0 - 8mol/L。方法已用于江水及井水样品中 NNA的测定 ,回收率 98.2 %～1 0 1 .9%,相对标准偏差 1 .2 %～ 1 .3%。     

固相萃取-高效液相色谱法同时测定克伦特罗和沙丁胺醇

提出用固相萃取 -高效液相色谱法同时测定饲料中微量克伦特罗和沙丁胺醇的新方法。选用 Dikma Diamonsil C18-ODS分析柱 (2 0 0× 4.6mm,5μm) ,乙腈 -0 .0 1mol/ L KH2 PO4 (p H 3 .0 )作流动相 ,应用波长编程进行检测。克伦特罗和沙丁胺醇的线性范围为 0 .1～ 1 0 0μg/ m L,相关系数分别为 0 .99999和 0 .99977,检出限分别为0 .3 1 ng/ m L和 0 .2 4ng/ m L ,回收率分别为 91 .2 %～ 92 .0 %和 91 .9%～ 93 .0 % ,相对标准偏差分别是 1 .2 0 %～ 2 .0 5%和 1 .2 9%～ 2 .51 %。     

纯铜、纯镍中磷的ICP-MS法测定

试验了31 P的ICP MS法的测定条件 ,建立了纯铜、纯镍中微量磷的测定方法。采用基体匹配消除基体影响 ,方法检出限为 0 .5 4ng/mL ,测定下限为质量分数 5 .4× 1 0 - 4 % ,回收率为 93.5 %～ 1 0 2 %。对于w(P) <1× 1 0 - 3%和w(P)≥1× 1 0 - 3%的试样 ,其RSD(n =5 )分别为 1 5 %和 6.1 %。本法与光度法分析结果一致 ,较光度法快速、简便     

甲苯胺蓝指示反应动力学光度法测定痕量钌

在磷酸和热水浴中 ,钌 (Ⅲ )对高碘酸钾氧化甲苯胺蓝的反应具有催化作用 ,据此建立了测定钌的新催化光度法。钌在 0～ 0 .0 5 0 μg/ 2 5ml范围内与催化反应速率有良好的线性关系 ,检出限为 5 .5 3× 10 - 5μg·ml- 1。对 0 .0 30 μg/ 2 5ml钌 (Ⅲ )测定的相对标准偏差为 2 .0 % (n =11)。该催化反应对钌 (Ⅲ )和甲苯胺蓝分别为一级反应 ,其表观活化能为 5 0 .2 6kJ·mol- 1。试验了 4 0多种共存离子的影响 ,大多数的常见离子不干扰。该方法用于岩矿和冶金产品中钌的测定 ,相对标准偏差为 2 .1%～ 2 .4 % ,标准加入回收率为 10 0 .1%～ 10 5 .4 %。     

乳酸氧化酶共价交联于蛋膜上制备乳酸传感器

以牛血清白蛋白 戊二醛为交联剂 ,将乳酸氧化酶固定于鸡蛋膜上 ,氧电极作电化学敏感元件 ,制成乳酸氧化酶电极。传感器的线性响应范围为 5 .0×1 0 - 5～ 2 .5× 1 0 - 2 mol/L ,检测限为 2 .0× 1 0 - 5mol/L ,RSD为 1 .4% (n =1 1 ) ,回收率为 97.5 %～ 1 0 4 .0 %。该传感器可用于临床乳酸的测定。     

1-脱氢松香酰基-3-取代硫脲以及5-(脱羧脱氢松香-4-基)-3-芳氨基- 1H-1,2,4-三唑化合物的合成与生物活性

以广西的优势资源松香为原料, 脱氢松香酸与亚硫酰氯、硫氰化钾分别在回流条件下反应6 h和1.5 h, 得到脱氢松香酰异硫氰酸酯, 产率52%; 然后与胺在加热回流条件下反应1.5 h, 得到11种1-脱氢松香酰基-3-取代硫脲4, 产率63%～94%; 4a～4f 分别与水合肼在搅拌下回流反应3～6 h, 得到6种5-(脱羧脱氢松香-4-基)-3-芳氨基-1H-1,2,4-三唑化合物5, 产率70%～94%; 所有化合物的结构均经IR, 1H NMR, 13C NMR和元素分析确认. 初步生物活性测试表明, 4e, 4f, 4j, 5b对枯草杆菌抑菌率较高, 特别是4j在浓度为50 mg/L时就达到较好效果; 4b, 4h, 4i, 5e在100 mg/L时对大肠杆菌的抑菌效果较好.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Copper catalyzed/mediated synthetic methodology for ebselen and related isoselenazolones

Scope of the copper catalyzed/mediated selenium-nitrogen coupling reaction has been studied for the synthesis of isoselenazolones. It is noticed that the 2-chloro, 2-bromo-, and 2-iodo-aryl amides substrates can be exploited in the selenium-nitrogen coupling reaction by employing 25-100 mol % of CuI/1,10-phenanthroline (L) and potassium carbonate as a base in DMF. Furthermore, electron rich 2-chloro-arylamides also underwent selenium-nitrogen coupling reaction to give biologically important selenium-nitrogen heterocycles. Also, copper-catalyzed selenium-nitrogen coupling reaction has been meticulously applied for the synthesis of diaryl diselenides having methoxy, amine, and amide functionality from respective aryl iodides in the presence of stoichiometric amount of succinimide as an external Se-N coupling partner.     

Knoevenagel condensation catalyzed by novel Nmm-based ionic liquids in water

A series of novel N-methyl morpholine (Nmm) based ionic liquids with 1,2-propanediol group were synthesized and used as catalysts for Knoevenagel condensation at room temperature in water. Under the effect of the catalyst, various aldehydes or aliphatic ketones could react with a wide range of activated methylene compounds well, including malononitrile, alkyl cyanoacetate, cyanoacetamide, β-diketone, barbituric acid, 2-arylacetonitrile and thiazolidinedione. Furthermore, most of the products could be separated just by filtrating and washing with water. Additionally, the catalyst is recyclable and applicable for the large-scale synthesis.     

Construction of polyheterocyclic spirotetrahydrothiophene derivatives via sulfa-Michael/aldol cascade reaction

A series of polyheterocyclic spirotetrahydrothiophene derivatives were obtained in moderate to excellent yields via a catalyst-free sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 under mild conditions. We also present the first asymmetric sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 with moderate to good enantioselectivities catalyzed by readily available chiral phase-transfer catalysts (PTCs).     

Suzuki-Miyaura reactions of the soluble guanylate cyclase inhibitor NS2028: a non-product specific route to C-8 substituted analogues

Both soluble guanylate cyclase (sGC) inhibitors ODQ 1 and NS2028 2 are synthesized via improved protocols. In the former case treating 3,4-dihydroquinoxalin-2(1H)-one oxime 8, which can be prepared in two steps from 1,2-benzenediamine, with 1,1′-carbonyldiimidazole (CDI) gives the dihydro-ODQ 10 that in the presence of KMnO₄ oxidises to give ODQ 1 in an overall yield of 46% starting from 1,2-benzenediamine. In the latter case, the synthesis affords NS2028 2 from 2-amino-4-bromophenol 3 in three steps with an overall yield of 85% and avoids the need for chromatography. Furthermore, Suzuki-Miyaura reaction conditions are described that enable the preparation of 8-aryl and 8-heteroaryl derivatives of NS2028 directly from NS2028 2. Finally, demethylation of the 8-(methoxyphenyl) substituted analogues afforded the 8-(hydroxyphenyl) derivatives 40-42. All new products are fully characterised.