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。     

离子对反相高效液相色谱法测定阿仑膦酸钠的含量

以四丁基溴化铵为离子对试剂,采用离子对反相高校液相色谱法,配以示差折光检测器(RI)检测,建立了用于阿仑膦酸钠含量测定的分析方法.以Agilent CLC-ODS C18柱为固定相,流动相为V(甲醇):V(水)=10:90,含5mmol/LNH4H2PO4,2mmol/L四丁基溴化铵,1.5 mmol/L乙二胺四乙酸二钠,用NaoH调节pH至7.2),流速为1.0 mL/min,柱温为室温.方法的线性范围为80～720mg/L;回归方程为A=0.3971ρ-10.624,r=0.9993;方法的平均回收率为100.0%;RSD为0.76%.在该色谱条件下,得到阿仑膦酸钠主峰.     

离子对反相高效液相色谱法分离伊班膦酸钠及其有关物质

采用离子对反相高效液相色谱法研究了伊班膦酸钠及其有关物质的色谱分离方法。以Inertsil C8色谱柱为固定相,乙腈．甲醇．12mmol／L乙酸铵缓冲液（含35mmol／L正戊胺,pH7．0）（8：4：88）为流动相,流速为1．0mL／min,分析物以通用型的蒸发光散射检测器（ELSD）测定。在该色谱条件下,伊班膦酸钠及其有关物质分离良好且能够被同时检测。本方法采用的可挥发离子对试剂和缓冲液的流动相系统,同时解决了伊班膦酸钠及其有关物质的分离与检测的问题,简单快速、专属性强,适用于伊班膦酸钠的有关物质检测,为该药的质量控制提供了简便可靠的分析手段。     

离子色谱积分脉冲安培法同时测定血浆中阿仑膦酸钠、帕米膦酸钠、伊班膦酸钠和利塞膦酸钠

建立了离子色谱积分脉冲安培检测器(IPAD)同时检测血浆中阿仑膦酸钠、帕米膦酸钠、伊班膦酸钠和利塞膦酸钠的方法。采用Dionex AS18 (250 mm×2 mm)和AG18 (50 mm×2 mm)色谱柱在24 mmol/L NaOH溶液中进行分离;对多电位波形参数优化以达到最大信噪比;采用优化后的波形方法对4种双膦酸盐类药物进行检测,具有良好的线性(r2为0.9972～0.9995)和重现性(峰面积的相对标准偏差(RSD)为0.84%～1.37%)及较高的灵敏度(检出限为0.061～0.18 μg/mL)。4种双膦酸盐在该方法中有很好的保留且有较好的分离度,与之前报道的衍生后检测方法相比,该方法不用衍生,更简单而易于操作。将该方法成功地用于人体血浆中双膦酸盐类的检测,其回收率为80.81%～97.32%, RSD为1.46%～3.02%。     

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。     

亲水相互作用色谱柱串联C18柱高效分析饮品中的胭脂红

建立了亲水相互作用色谱柱(HILIC)串联C18柱的方法,高效分离实际样品中的胭脂红,并对色谱柱的串联顺序以及色谱分离条件进行优化。结果表明:当HILIC柱在前C18柱在后,流动相为乙腈-乙酸铵(5 mmol/L)=91∶9(V/V),流速为0.9 mL/min,柱温为25℃,检测波长为508 nm时,此时胭脂红的分离效果最佳。在最佳的色谱分离条件下,选用两种市售饮品进行实际样品的测定,回收率在81.2%~119%。方法适用于水相样品中的强极性物质的高效分离与分析。     

2-戊基-3-苯基-2,3-环氧丙醇对映体在手性柱上的拆分研究

采用多糖类手性固定相,建立2-戊基-3-苯基-2,3-环氧丙醇对映体的高效液相色谱(HPLC)手性分析方法。考察了手性柱类型、流动相组成、流速及柱温对2-戊基-3-苯基-2,3-环氧丙醇对映体拆分的影响。结果表明,以Chiralcel OD-H色谱柱(25×0.46cm,5μm)分离,采用正己烷-异丙醇(V/V,90∶10)作流动相,在流速为0.8 mL·min-1,柱温25℃,检测波长210nm的条件下,2-戊基-3-苯基-2,3-环氧丙醇对映体能达到基线分离,且具有较好的重复性和稳定性,可用于对映体的拆分及质量控制。该方法也适用于2-戊基-3-苯基-2,3-环氧丙醇类似物质的手性拆分。     

某些酚类的高温液相色谱行为

建立了高温液相色谱系统,在高温条件下,采用甲醇-水作为流动相,在Polymerx RP-1聚合物(PSDVB)色谱柱上考察了6种酚类样品的色谱行为.实验条件:温度40～160 ℃,流速0.2～5.5 mL/min,流动相中甲醇浓度范围40%～80%.考察了温度、流速和流动相组成对酚类样品的保留、分辨、柱效和系统压力的影响,探讨了酚类样品在聚合物柱上的热力学行为.温度升高2.35℃大约相当于流动相中甲醇浓度增加1%,可以通过改变色谱柱温度调节样品保留和改变选择性.柱温升高,降低了流动相的粘度,允许在高温条件下使用较高的流速实现快速分离.在160℃、V(甲醇):V(水)=40:60,为流动相和3 mL/min流速条件下,可于2.5 min内实现6种酚类的完全分离.     

高效液相色谱-串联质谱法结合多糖衍生物手性固定相拆分氰戊菊酯

建立了以多糖衍生物为手性固定相的高效液相色谱-串联质谱(HPLC-MS/MS)直接拆分氰戊菊酯对映体的方法。在反相液相色谱条件下,考察了手性固定相的种类、流动相组成、柱温、流速对氰戊菊酯4个立体异构体分离的影响。同时,利用热力学方法对氰戊菊酯的立体异构体与固定相之间的色谱保留和分离的热力学机理进行了探讨。结果表明:采用Lux Cellulose-3(纤维素-三(4-甲基苯甲酸酯))手性色谱柱,在以流动相为乙腈-水(5 mmol/L甲酸铵)=(55:45,V:V)流速0.4 mL/min,柱温30℃的条件下,可在14 mins内实现氰戊菊酯4个立体异构体的基线分离。拓展了HPLC-MS/MS在菊酯类手性农药对映体分离及检测上的应用。     

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%.     

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.     

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.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

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.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.