3-吲哚羧酸的性质对其印迹聚合物印迹效率的影响

以3-吲哚丙酸(IPA)和3-吲哚丁酸(IBA)为模板分子,4-乙烯基吡啶(4-Vpy)为功能单体,乙二醇二甲基丙烯酸酯为交联剂,乙腈为致孔剂,利用非共价本体聚合法,制备了印迹聚合物P(IPA)和P(IBA),并用色谱法评价了其分子识别性能。结果表明,P(IPA)和P(IBA)分别对IPA和IBA具有分子识别能力,静电作用在其分子识别过程中起重要作用。此外,对P(IPA)、P(IBA)和同样条件下制备的3-吲哚乙酸(IAA)印迹聚合物P(IAA)的分子识别能力进行了比较,乙腈为流动相时,P(IAA)、P(IPA)和P(IBA)对各自模板分子的印迹因子IF值分别为大于6.00,4.27和2.28,即随着3-吲哚羧酸羧基碳链的增长,其印迹效率降低。结果表明,在P(IPA)和P(IBA)中,分别存在与对应的模板分子互补的印迹空穴;随着3-吲哚羧酸酸性的降低,印迹聚合物的印迹效率降低。     

固相萃取—化学发光法测定植物中的吲哚乙酸

植物拟南芥中吲哚乙酸用甲醇超声提取,后经固相萃取小柱净化用化学发光法测定.在多聚磷酸(PPA)介质中,吲哚乙酸对高良姜素-高锰酸钾体系的发光有很强的增敏作用,据此建立了固相萃取-流动注射化学发光测定吲哚乙酸的新方法.在优化条件下,相对化学发光的对数值与吲哚乙酸浓度的对数值在8.0 ×10-9～1.0×10 -7g/mL...     

吲哚美辛在单壁碳纳米管修饰电极上的电化学行为

运用伏安法研究了吲哚美辛在单壁碳纳米管修饰电极上的电化学行为.在0.1 mol/L HAc-NaAc缓冲溶液(pH 4.5)中,吲哚美辛于0.91 V (vs.SCE)电位处有一个峰形很好的氧化峰.与裸玻碳电极相比,吲哚美辛在修饰电极上的电位正移了约30 mV,峰电流增加了近10倍,表明该修饰电极对吲哚美辛有较强的电催化作用.搅拌条件下开路富集2 min,氧化峰电流与吲哚美辛在5.5×10-7～1.1×10-5 mol/L浓度范围内呈良好的线性关系,检出限为1.1×10-7 mol/L.该方法可用于药剂中吲哚美辛的分析.     

离子色谱法测定水果和蔬菜中3-吲哚乙酸和3-吲哚丁酸的含量

水果或蔬菜样品(5.00g)采用含10%(体积分数)乙腈的35mmol·L~(-1)氢氧化钠溶液45mL超声提取,萃取液经固相萃取C18小柱净化后,选用AS11分离柱(4mm×250mm)进行色谱分离,用与上文中相同的乙腈-氢氧化钠混合液为流动相。用紫外检测器测定。3-吲哚乙酸和3-吲哚丁酸的质量浓度均在0.05~10g·L~(-1)内与其对应的峰面积呈线性关系,两者的检出限(3S/N)依次为0.009,0.012g·L~(-1)。对10g·L~(-1)的3-吲哚乙酸和3-吲哚丁酸的混合标准溶液连续测定6次,峰面积的相对标准偏差依次为0.14%,1.4%。在0.50,2.0,10g·L~(-1)等3个浓度水平进行加标回收试验,回收率在77.1%~104%之间。     

水溶液微悬浮聚合法制备酸性药物吲哚美辛分子印迹微球及其色谱表征

以带有羧基的酸性药物吲哚美辛为模板分子、碱性的4-乙烯基吡啶为功能单体,采用水溶液微悬浮聚合法制备了用于色谱分离的微米级分子印迹微球.详细讨论了流动相中缓冲溶液的pH值对吲哚美辛在MIMs柱上的容量因子(k′)、分离因子(α)和印迹因子(β)的影响.通过MIMs柱对吲哚美辛和4-氨基吡啶(4-AP)的保留行为的比较,证明以4-乙烯基吡啶为功能单体制得的MIMs对吲哚美辛的识别作用,主要靠吡啶环上氮原子与吲哚美辛羧基之间的离子键相互作用,以及吡啶环与模板分子之间的π-π相互作用.     

自支撑柔性聚(5-吲哚硼酸)膜的电化学合成及表征

在三氟化硼乙醚/乙腈的混合体系中,5-吲哚硼酸的电化学氧化可以获得导电率为9×10-4 S·cm-1的自支撑柔性聚(5-吲哚硼酸)膜.5-吲哚硼酸在80％的三氟化硼乙醚亿腈溶液中的起始氧化电位约为0.80V红外光谱确定了5-吲哚硼酸的聚合位点在C2和C3位上.紫外可见光谱测试结果表明聚(5-吲哚硼酸)的能隙约为2.48...     

水杨酸分子印迹电化学传感器的制备及其性能研究

以水杨酸作为模板分子,通过原位聚合法,在玻碳电极表面合成了水杨酸分子印迹聚合物膜,并用方波伏安法对该印迹电极进行了分析研究.当吸附时间为7 min时,印迹电极对水杨酸浓度响应的线性范围为1.0×10-5~2.6×10-5mol/L,检出限(S/N=3)为2.0×10-6mol/L,同一支印迹电极对水杨酸响应值的RSD为...     

无保护流体室温燐光法同时测定α-萘乙酸和吲哚-3-乙酸

利用重原子效应(HAE)的选择性,建立了一种仅用TlNO3和KI为重原子微扰剂(HAP)、Na2SO3为除氧剂的无保护流体室温燐光(NP-RTP)同时测定α-萘乙酸(NAA)和吲哚-3-乙酸(IAA)的方法。吲哚-3-乙酸(KI为HAP)、α-萘乙酸(TlNO3为HAP)和α-萘乙酸(KI为HAP)的最大激发/发射峰分别位于280/448nm、280/490nm和280/490nm,线性范围分别为2.5×10-7~1.0×10-5mol/L、1.0×10-7~6.5×10-6mol/L和6.5×10-7~1.0×10-5mol/L,检出限分别为6.5×10-8mol/L、7.1×10-8mol/L和1.98×10-7mol/L。该方法已用于商品萘-吲可湿性粉剂中α-萘乙酸和吲哚-3-乙酸的同时测定,回收率和相对标准偏差分别为95.3%~104.7%和1.8%~4.6%。     

异丙隆分子印迹敏感膜传感器

在弱酸(pH 5.5)条件下,采用电聚合法在金电极上制备邻氨基酚异丙隆分子印迹膜,对该印迹膜的性能、分子印迹效应和印迹膜对模板分子及其结构相似物的选择性响应等进行了研究.以K3Fe(CN)6为印迹电极和底液间的探针,建立了一种检测异丙隆的方法.该传感器对异丙隆具有良好的选择性和敏感度,异丙隆浓度在1.0×10-7～4.0×10-4 mol/L范围内与K3Fe(CN)6还原峰电流减少量呈线性关系; 检出限为2.95×10-8 mol/L.对农田水中异丙隆含量进行了测定,回收率为99.0%～102.0%.     

3-吲哚基-3-甲硫基丙烯酸酯和3-吲哚基-3-氧代丙酸酯的选择性合成

在10℃,3,3-二甲硫基丙烯酸酯、吲哚和三氟乙酸(TFA)的物质的量之比为1∶1∶15时,研究了3,3-二甲硫基丙烯酸酯的吲哚化反应.通过控制产物在硅胶的停留时间选择性制备了3-吲哚基-3-甲硫基丙烯酸酯(83%~85%)和3-吲哚基-3-氧代丙酸酯(83%~89%).反应条件温和、操作简单、产率高且选择性好.     

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%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

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.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

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.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.