反相离子对色谱/蒸发光散射检测器分离唑来膦酸及其有关物质

采用反相离子对高效液相色谱／蒸发光散射检测法研究了唑来膦酸及其有关物质的色谱分析与分离方法。优化了色谱条件，固定相为Hypersil C8柱，以含10 mmol／L正戊胺的5mmol／L乙酸铵缓冲液（用乙酸调节pH至7．0）-甲醇（体积比为97：3）为流动相，流速为1．0mL/min，蒸发光散射检测器检测。在该色谱条件下，唑来膦酸与其有关化合物（包括合成过程中残余的原料咪唑乙酸及分解产物亚磷酸、磷酸盐）的分离良好，唑来膦酸色谱峰与最近杂质峰的分离度大于1．5。本法简便快速，为唑来膦酸的常规分析提供了有效可靠的方法。     

依替膦酸钠及其有关物质的反相离子对色谱分析

建立用于依替瞵酸钠含量测定及有关物质俭查的分析方法。采用反相离子对高效液相色谱法,蒸发光散射俭测器检测,以Hypersil C8 BDS柱为固定相,流动相为甲醇-含8mmol／L正戊胺的5mmol／L乙酸铵缓冲液(用乙酸调节pH至7．0)(体积比为5：95),流速为1．0mL／min,柱温为室温,方法的线性范围为110～994μg／mL,回归方程为lg A=2．105lg ρ 1．972(r=0．9999)方法的回收率为99％～102％．RSD为0．70％(n=9)．在该色谱条件下．依替膦酸钠与其有关物质(包括残留的合成原料亚磷酸及氧化分解产物磷酸盐)的分离良好：本法不需特殊的样品处理过程．快速,特异性好．适用于依替瞵酸钠的常规检测,为该药的质量控制提供了新的可靠的分析手段。     

加压毛细管电色谱手性配体交换法对游离亮氨酸异构体分离的研究

以反相C18为固定相,通过对流动相中的手性选择体、流动相组成与pH值及操作电压等条件的考察,成功建立了毛细管电色谱（CEC）手性配体交换法分离游离亮氨酸异构体的方法。优化的色谱条件：C18反相毛细管柱;以2mmol／L天冬氨酰苯丙氨酸甲酯为手性选择体,Cu^2＋为配体离子,流动相为20mmol／L乙酸缓冲液（pH5．5）,5％（体积分数）的甲醇为有机改性剂;流速为0．02mL／min;操作压力为6．9×10^6 Pa;检测波长为UV 280nm;工作电压＋5kV;室温。两异构体可在15min内基线分离,检出限为10μmol／L（S／N=3）,并在0．05～1．5mmol／L范围内呈良好的线性关系,日让、日内精密度均小于3．5％。     

球状苯基纤维素填料在低压疏水制备色谱分离天然菠萝酶中的应用

通过将苯环接技于球状大孔纤维素白球的方法,得到一类以大孔球状纤维素为基质的大型流水性工业色谱填料,并研究了其分离天然菠萝酶的色谱条件。色谱代化条件为：流动相100mL,含1．5mol／L（NH4）2SO4,0.1mol／LNaAc－HAc（pH4．8）缓冲液;洗脱液3OmL．含67mmol／LNaOH,50mmol／LNa2CO3－NaHCO3缓冲液（pH10.28）;流速1．0mL／min。在此条件下使用该填料10mL分离提纯天然菠萝酶,可得到大于120％的活性回收率。     

用反相离子对色谱-蒸发光散射检测法研究阿仑膦酸钠及其相关物质的分离

采用反相离子对色谱-蒸发光散射检测法,研究了阿仑膦酸钠及相关物质的色谱分离。选择的色谱条件是:固定相为Intersil C8(150×4.6 mm i.d.,5μm)柱,以52mmol.L-1正戊胺水溶液(用乙酸调节pH至7.0)-甲醇(98∶2,V/V)为流动相,流速为1.0 mL.min-1,柱温为室温。在该色谱条件下,阿仑膦酸钠与其有关物质(包括合成过程中残余的原料4-氨基丁酸、亚磷酸及分解产物磷酸盐)分离良好。本法简便、快速,为阿仑膦酸钠的常规分析及质量控制提供了一种可靠而有效的手段。     

唑来膦酸及其有关化合物的反相离子对高效液相色谱分离

采用反相离子对高效液相色谱法研究了唑来膦酸及其有关化合物的色谱分析与分离方法。优化的分离条件：以Hypersil C8柱为固定相,以甲醇-5 mmol/L磷酸二氢钠缓冲液(含6 mmol/L四丁基溴化铵溶液,用氢氧化钠溶液调节pH至7.0)(体积比为20∶80)为流动相,等度洗脱,流速为1.0 mL/min,紫外检测波长为220 nm,柱温为室温。在该色谱条件下,唑来膦酸与有关化合物(包括其合成过程中残余的原料咪唑乙酸和其他氧化分解产物)的分离良好,与保留时间最接近的杂质峰的分离度大于2.5。该方法不需进     

离子对反相高效液相色谱法测定阿仑膦酸钠含量及其有关物质

以挥发性的正戊胺作为离子对试剂,采用离子对反相高效液相色谱法,配以蒸发光散射检测器(ELSD)检测,建立了用于阿仑膦酸钠含量测定及相关物质检查的分析方法。以Iintersil C8柱为固定相,流动相为50 mmol/L正戊胺水溶液(用乙酸调节pH至7.0)-甲醇(98∶2),流速为1.0 mL/m in,柱温为室温。方法的线性范围为200~1000 mg/L;回归方程为lgA=2.5884 lgC-0.243,r=0.9990;方法的平均回收率为100.4%;RSD为0.65%。在该色谱条件下,阿仑膦酸钠与其有关物质(包括残留的合成原料亚磷酸及氧化分解产物磷酸盐)的分离良好,且样品测定不受辅料干扰。样品测定结果满意。本法不需特殊的样品处理过程,快速,特异性好,适用于阿仑膦酸钠的常规检测及有关物质检查,为该药的质量控制提供了可靠的分析手段。     

使用限进介质色谱柱的柱切换高效液相色谱法直接进样测定大鼠血浆中舒必利

提出一种直接进样测定大鼠血浆中舒必利浓度的高效液相色谱方法,使用限进介质色谱柱作为预柱在线去除血浆蛋白后,将舒必利通过柱切换转移到分析柱中进行分析。限进介质色谱柱为CAPCELLPAKMFSCX阳离子交换柱（20×4．0mmi．d．,5μm）,分析柱为Kromasil C18柱（150×4．6mm i．d．,5μm）,限进介质柱预分离时流动相为PH=6．88的50mmol／L磷酸盐缓冲液乙腈（100：5,V／V）,切换后分析流动相为PH=6．83的50mmol／L磷酸盐缓冲液-乙腈（100：10,V／V）。流速均为1mL／min,检测波长为240nm。该方法检出限为17ng／mL,定量限为50ng／mL。舒必利在50～1400ng／mL之间线性良好（r=0．9997）,高中低浓度的日内、日间相对标准偏差分别为1．5％～4．2％及2．0％～5．2％,方法回收率为98．8％～104．1％．     

离子色谱法测定伊班膦酸钠中的亚磷酸和磷酸根离子

建立了离子色谱–抑制电导法检测伊班膦酸钠中亚磷酸根和磷酸根离子的方法。实验采用SH–AC–1型离子交换色谱柱,3.6 mmol/L碳酸钠–4.5 mmol/L碳酸氢钠为淋洗液,流量为1.5 m L/min,进样体积为20μL。在此条件下,可同时分离亚磷酸和磷酸根离子,且色谱峰型对称。所测H2PO3–,H2PO4–离子的检出限(S/N=3)分别为0.027,0.053 mg/L。应用该方法测定H2PO3–,H2PO4–离子,加标回收率分别为95.7%~108.1%,99.8%~107.7%,测定结果的相对标准偏差分别为2.5%,5.6%(n=6)。该方法简单,测定结果准确、可靠,可以用于实际生产中监测伊班膦酸钠的质量。     

HPLC-ICP-MS或HPLC-FAAS法分离测定硒化合物（英文）

提出了一种用高效液相色谱（HPLC）分离和用电感偶合等离子体质谱仪（ICP－MS）或火焰原子吸收光谱仪（FAAS）作元素专一检测器在线测定硒的化学形态的方法。在优化的HPLC条件下,用ESAⅢ阴离子色谱柱（250mm×4．6mm）,以柠檬酸铵为流动相（5．5mmol／L,pH5．5,流速1．5mL／min）,进样量100μL,分离和测定三甲基硒离子、硒代蛋氨酸、亚硒酸和硒酸盐只需8min。HPLC－FAAS在线分析4种硒化合物的检测限为p（Se）=1mg／L。用超声雾化器作ICP－MS的接口,HPLC－ICP－MS在线分析4种硒化合物的检测限分别为P（Se）=0．34μg／L（亚硒酸）,0．18μg／L（硒代蛋氨酸）,0．08μg／L（三甲基硒离子）和0．07μg／L（硒酸盐）。与气动雾化器接口相比,信号强度增加7至31倍。     

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.