OPA-FMOC在线柱前衍生化HPLC法测定甘露聚糖肽中氨基酸组成及含量

建立了OPA-FMOC在线柱前衍生化高效液相色谱法测定甘露聚糖肽中氨基酸组成及含量的方法,采用色谱柱为Agilent ZORBAX Eclipse XDB-C18柱(250 mm×4.6 mm,5μm),流动相A为40 mmol/L Na_2HPO_4缓冲溶液(pH 7.8);流动相B为甲醇:乙腈:水(45∶45∶10,V/V/V);梯度洗脱;流速:1.5 m L/min;柱温:40℃;检测波长:338,262 nm。20种氨基酸在53 min内得到较好地分离,各氨基酸在5~500μg/m L范围内线性关系良好,相关系数在0.9941~0.9999之间;平均加标回收率在85.6%~102.6%之间;检出限在0.56~8.33 ng(进样量1μL)范围内。甘露聚糖肽样品中含有16种氨基酸,氨基酸总量平均为3.56%(n=3)。     

反相液相色谱法同时测定原料药中吉非替尼及其有关物质的含量

采用Phenomenex Gemini C18色谱柱,以乙腈-0.15%醋酸铵缓冲液为流动相,紫外检测器检测,通过对流动相组成、缓冲溶液浓度、p H值、检测波长等色谱条件进行研究,建立了同时测定原料药中吉非替尼及其有关物质含量的反相高效液相色谱法。结果表明:以乙腈-0.15%醋酸铵缓冲溶液(p H 8.5)为流动相,流速1.0 m L/min,检测波长255 nm,在40℃柱温下采用梯度洗脱可较好地分离原料药中吉非替尼及其9种有关物质;吉非替尼及其有关物质的质量浓度在0.012 0~4.202μg/m L范围内呈良好线性关系(r0.999 0),检出限为0.001 7~0.094 1μg/m L,平均回收率和相对标准偏差(RSD)分别为99.7%~100.9%和0.06%~0.70%。该法已成功应用于吉非替尼原料药主成分及有关物质的同时测定,且检测灵敏度高,重现性好,结果准确可靠,可作为吉非替尼原料药质量控制的标准。     

高效液相色谱法测定培美曲塞二钠原料药中有关物质

建立了高效液相色谱法测定培美曲塞二钠原料药有关物质的方法。采用Zorbax SB-C8(4.6 mm i.d.×150 mm,3.5μm)色谱柱,以0.025 mol/L乙酸钠溶液(用冰乙酸调p H至5.5)为流动相A,乙腈为流动相B,梯度洗脱,流速为1.0 m L/min;柱温35℃;检测波长250 nm;进样体积20μL。在该条件下主成分与有关物质的分离度良好,在测定的范围内具有良好的线性关系(相关系数r0.999)、精密度和稳定性。方法能够对培美曲塞二钠原料药的主要杂质进行有效的分离和检测,可用于该产品的质量控制。     

高效液相色谱-四极杆/线性离子阱质谱测定替米沙坦中N-甲基邻苯二胺残留量

建立了高效液相色谱-四极杆/线性离子阱质谱(HPLC-QTRAP-MS/MS)测定替米沙坦中N-甲基邻苯二胺残留量的分析方法。替米沙坦药物以水-乙腈(80∶20,体积比)溶解后,采用Agilent Eclipse XDB-C18色谱柱(3.5μm,2.1 mm×100 mm)进行分离,以0.1%(体积分数)甲酸水和乙腈作为流动相进行梯度洗脱,电喷雾正离子(ESI+)扫描方式下选择离子监测(SRM)模式对样品进行检测。结果表明,N-甲基邻苯二胺在2.0~50μg/L范围内线性关系良好(r0.99),检出限(S/N=3)为0.5μg/L,定量下限(S/N=10)为2.0μg/L。该方法操作简单、灵敏度高、重现性好,可用于替米沙坦中N-甲基邻苯二胺残留量的测定。     

超高效液相色谱-串联质谱法测定食品中4种罂粟壳生物碱

建立了超高效液相色谱-串联质谱法(UPLC-MS/MS)测定食品中可卡因、可待因、吗啡、盐酸罂粟碱的检测方法.样品经氨化甲醇提取,采用Capcell Pak C_(18)(250 mm×2.0 mm,MGⅡ 5μm)色谱柱,以色谱纯乙腈为流动相A,以20 mmol/L乙酸铵和0.1%甲酸缓冲液为流动相B,进行梯度洗脱.在优选条件下,可待因、吗啡方法线性范围为5.0~50.0μg/L,可卡因、盐酸罂粟碱的方法线性范围为1.0~20.0μg/L,相关系数均大于0.999,方法检出限在0.1~0.8μg/kg之间,平均回收率为76.0%~111.2%,相对标准偏差RSD低于10%.     

高效液相色谱法测定马来酸麦角新碱注射液中甲硫氨酸

建立高效液相色谱法测定马来酸麦角新碱注射液中甲硫氨酸含量的方法。采用Venusil HILIC色谱柱（250 mm×4.6 mm, 5μm），以5 mmol/L磷酸氢二钾溶液（用磷酸调节pH值至6.9）-乙腈（体积比为20∶80）为流动相，流量为1.0 mL/min，柱温为30℃，检测波长为215 nm。结果表明，甲硫氨酸质量浓度在20～400μg/mL范围内与色谱峰面积的线性关系良好，相关系数为0.999 9，检出限和定量限分别为0.5、1.6μg/mL，平均加标回收率为99.7%，测定结果的相对标准偏差为0.3%(n=6)。该方法适用于测定马来酸麦角新碱注射液中甲硫氨酸的含量。     

液相色谱-串联质谱法测定育肥猪配合饲料中的阿奇霉素

通过对提取溶剂、净化方法及色谱-质谱条件的优化,建立了配合饲料中阿奇霉素(AZM)的液相色谱-串联质谱测定方法。样品经乙腈超声波提取,MCX固相萃取柱净化,BDS Hypersil C_(18)(2.4μm,100 mm×2.1 mm)色谱柱分离,以甲醇-0.05 mol/L乙酸铵水溶液为流动相梯度洗脱,正离子模式电离,多反应监测模式检测,同位素内标法定量。在优化条件下,AZM在1~250μg/L范围内线性关系良好,相关系数(r~2)为0.999 1,检出限(S/N≥3)为2.8μg/kg,定量下限(S/N≥10)为8.4μg/kg;在0.5,1,5,10 mg/kg加标水平下,回收率为87.0%~106.6%,批内相对标准偏差为0.58%~5.4%,批间相对标准偏差为3.1%~5.4%。该方法准确、灵敏,选择性强,基质干扰小,可用于配合饲料中AZM的测定。     

固相萃取-高效液相色谱法同时测定牛奶中13种磺胺残留

建立了固相萃取-高效液相色谱同时测定牛奶中13种磺胺类药物残留的方法。样品经乙腈溶液漩涡超声提取后,采用自制碱性氧化铝固相萃取小柱(SPE)净化,洗脱液减压浓缩至近干后用流动相溶解并定容,过PTFE滤膜后在Thermo Fisher Scientific ODS hypersil色谱柱上,以乙腈-20 mmol/L H3PO4溶液为流动相进行梯度洗脱,检测波长为270 nm。13种磺胺在50~5000μg/L范围内具有良好的线性,相关系数≥0.999,检出限为2.0~4.2μg/L,定量限为8.9~14.2μg/L。在20,50,100μg/L添加水平的加标回收率为79.0%~118.2%,相对标准偏差在2.7%~6.9%之间。方法能对牛奶中13种磺胺类药物残留实现准确定量分析。     

自制混合型固相萃取柱-高效液相色谱法同时测定食品中黄曲霉毒素B1、M1

建立了基于自制混合型固相萃取柱的样品净化/高效液相色谱测定食品中黄曲霉毒素B1、M1的方法。样品经60%乙腈水溶液提取、离心后,通过自制固相萃取柱排除杂质干扰,流出液以Shim-pack VP-ODS C18色谱柱为分离柱,水和乙腈为流动相,用荧光检测器检测,外标法定量。考察了柱类型、柱容量、取样量、提取溶液和流速等对检测的影响,优化了实验条件。在优化条件下,2种毒素在0.40～100μg/L质量浓度范围内与峰面积呈良好的线性关系,相关系数为0.999 4～0.999 7,检出限(S/N=3)为0.050μg/kg。在样品中分别加入0.40、1.0、100μg/L 3种浓度水平的标准品,其加标回收率为53%～112%,相对标准偏差为2.7%～7.1%。该法灵敏度高,操作简单﹑快速,适用于花生、开心果和奶粉等食品中痕量黄曲霉毒素B1和M1的测定。     

HPLC法直接同时测定大鼠毛发中的胱氨酸、酪氨酸及组氨酸

建立了同时测定大鼠毛发中胱氨酸、酪氨酸和组氨酸的高效液相色谱(HPLC)检测方法。优化了色谱分离及检测条件,样品经酸解后进样分析。采用Titank C18色谱柱(4. 6 mm×250 mm,5μm),以10 mmol/L磷酸氢二铵缓冲液(含10 mmol/L 1-辛烷磺酸钠,用磷酸调至p H 2. 0)-乙腈为流动相,进行梯度洗脱,流速1. 0 m L/min,检测波长205 nm,进样体积为100μL,柱温为8℃。结果表明,在优化条件下,大鼠毛发中的胱氨酸、酪氨酸和组氨酸能实现有效分离。3种氨基酸的线性良好,相关系数(r)均大于0. 999;检出限(S/N=3)为49～442μg/L;定量下限(S/N=10)为148～884μg/L;样品的平均加标回收率为97. 8%～102%,相对标准偏差(RSD)为0. 1%～1. 6%。该方法操作简便、准确可靠、重现性好,可用于大鼠毛发中胱氨酸、酪氨酸和组氨酸的检测。     

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.