鲁米诺-高锰酸钾-苯酚化学发光体系研究

基于鲁米诺-高锰酸钾-苯酚体系很好的化学发光特性,建立一种测定苯酚的流动注射化学发光分析新方法。在最优化实验条件下,苯酚浓度在0．001—2．5mg／L范围内与化学发光强度呈良好的线性关系,标准曲线为ΔI=750．45C(mg／L) 1．4655(n=8,r^2=0．9998),检出限(3σ)为0．35μg/L;对0．05和0．5mg／L的苯酚进行11次平行测定,相对标准偏差(RSD)分别为0．6％和2．5％。应用本法于合成样品和工业废水中苯酚的测定,结果令人满意。     

流动注射-化学发光法测定盐酸洛美沙星

在酸性条件下盐酸洛美沙星可与Ce(Ⅳ)产生化学发光反应，罗丹明6G对该反应有较强的增敏作用。据此，建立了流动注射-化学发光法测定盐酸洛美沙星的新方法。该方法的线性范围为0．10～15．0mg／L，检出限为0．06mg／L，相对标准偏差(n=11，c=1．00mg／L)为1．2％，回收率为95％～102％。本法用于胶囊中盐酸洛美沙星含量的测定，分析结果满意。     

鲁米诺-过硫酸钠化学发光体系测定硝苯地平

过硫酸钠在碱性条件下能氧化鲁米诺产生微弱化学发光,硝苯地平能大大增强此发光。基于此．建立起了一种直接测定硝苯地平的流动注射化学发光方法。该方法线性范围为0．05～5．0mg／L;检出限为0．017mg/L;相对标准偏差为2．8％(硝苯地平0．5mg／L,n=11)。利用该方法测定了硝苯地平片剂含量,结果令人满意。     

流动注射化学发光抑制法测定氨苄西林钠

基于氨苄西林钠在H2SO4溶液中降解后,其降解产物对桑色素-KMnO4体系的化学发光具有显著的抑制作用,据此建立了流动注射化学发光抑制法快速测定氨苄西林钠的新方法。化学发光信号的降低值△Icl与氨苄西林钠的质量浓度在10．0～100．0mg／L范围内呈良好的线性关系,其中r=0．9995(n=7)。方法的检出限为2．7mg／L,对50．0mg／L氨苄西林钠进行了11次平行测定,方法的相对标准偏差为0．8％。用本法对氨苄西林钠针剂的测定结果符合国家药典要求,回收率为99．1％～102．0％。初步探讨了化学发光反应的抑制机理。     

流动注射化学发光法测定氧乐果

基于氧乐果的水解反应和巯基化合物一铈(Ⅳ)的化学发光反应,以罗丹明B作为增敏剂,建立了痕量氧乐果的流动注射．化学发光分析方法。该方法的线性范围和检出限分别为0．04～14．00mg／L和0．02mg／L,相对标准偏差(n=11,ρ=1．00mg／L)为0．9％。该方法已用于废水水样的分析。     

流动注射化学发光法检测水相中溶解臭氧浓度

基于碱性水溶液中臭氧氧化鲁米诺产生化学发光的现象,建立了利用流动注射化学发光技术检测水体溶解臭氧(DO3)的方法。检测了较高和较低两部分的DO3浓度范围,低浓度DO3从20μg/L到65μg/L,工作曲线为y=27．658In(X)-192．75;检出限为8．5μg/L(7次空白信号检测);高浓度D03从0．089mg／L到0．890mg／L,线性关系为y=0．0018x-23．711。溶液中的。DO3由靛蓝二磺酸钠法确定。随后利用化学发光系统检测鼓人臭氧气体的自来水,由工作曲线可以确定自来水中DO3的量。方法简便,结果准确。     

阿昔洛韦-过氧化氢-钴(Ⅱ)化学发光体系的研究和应用

在碱性介质中,Co^2 催化H2O2氧化阿昔洛韦产生强的化学发光。基于此,结合流动注射技术,建立了阿昔洛韦的化学发光测定新方法。该方法简单、快捷,测定阿昔洛韦的线性范围为0．8—60mg／L;检出限为0．2mg／L(3σ);对0．8mg／L的阿昔洛韦进行11次测定,计算出方法的相对标准偏差为6．3％。将此方法用于片剂中阿昔洛韦含量的测定,结果令人满意。     

高效液相色谱法测定氢化可的松发酵液中的氢化可的松及其有关物质

建立了用高效液相色谱法对氢化可的松发酵液中的主要组分氢化可的松(HC)、表氢化可的松(EHC)、17α-羟基孕甾-4-烯-3,20-二酮-21-醋酸酯(RSA)和17α-羟基孕甾-4-烯-3,20-二酮(RS)进行测定的方法。采用硅胶吸附色谱柱,以二氯甲烷-乙醚-甲醇-水(体积比为385∶60∶30∶2)为流动相,流速0.8 mL/min ,在242 nm波长下检测。发酵液各组分分离良好,HC,EHC,RSA和RS的线性范围分别为25～375 mg/L ,5～75 mg/L ,5～75 mg/L     

流动注射壳聚糖在线微柱预富集火焰原子吸收光谱法测定痕量钯

报道了壳聚糖作在线微柱预富集柱填料,流动注射与火焰原子光谱联用(FI-FAAS)测定痕量Pd的方法。当采样体积13．5mL时,采样频率27／h,富集倍数49倍,线性范围0．01～0．4mg／L,检出限(3s,n=11)1．4μg／L,相对标准偏差1．26％(Cpd=0．2mg／L,n=11)和4．0％(Cpd=0．05mg／L)。初步探讨了该过程的吸附机理。将该方法用于催化剂样品中痕量Pd的测定,结果满意。     

N-溴代琥珀酰亚胺-荧光素体系流动注射能量转移化学发光法测定妥布霉素

在碱性条件下,N-溴代琥珀酰亚胺(NBS)氧化妥布霉素,在荧光素增敏作用下发生化学发光。基于此,结合流动注射技术,建立了测定痕量妥布霉素的流动注射化学发光分析法。在优化的实验条件下,体系对妥布霉素的测定线性范围为0．2—100mg／L;检出限(3σ)为0．07mg／L;对5．0mg／L妥布霉素进行11次平行测定,其相对标准偏差为2．1％。将本法用于制剂和血样中妥布霉素的分析,结果令人满意。     

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.