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。     

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。     

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。     

离子色谱法测定氯膦酸二钠及其制剂的含量和有关物质

采用抑制型电导检测-离子色谱法同时测定氯膦酸二钠及其制剂的含量和有关物质.色谱条件为阴离子交换色谱柱(IonPac AS11-HC);检测方式为抑制电导检测;柱温30 ℃;流速1.2 mL/min;以KOH溶液为淋洗液,含量测定采用等度洗脱,有关物质检查采用梯度洗脱.氯膦酸二钠在0.0568～0.1895 g/L范围内线性关系良好(r＝0.9999); 注射液和胶囊的平均回收率分别为100.1%(RSD=0.7%)和98.9%(RSD=0.6%);检出限为0.3 ng.各杂质与主成分色谱峰能完全分离.     

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%。     

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。     

高效液相色谱-串联质谱法检测茶叶中痕量草胺膦、草甘膦及其代谢物氨甲基膦酸残留

建立高效液相色谱–串联质谱法测定茶叶中除草剂草胺膦、草甘膦及其代谢物氨甲基膦酸残留的方法。以纯水提取茶叶中的草胺膦、草甘膦、氨甲基膦酸,用二氯甲烷、阴离子交换固相萃取柱净化、富集,以0.25 mol/L碳酸氢钠溶液洗脱,然后直接采用1%芴甲氧羰酰氯进行衍生,衍生时间为5 min,用反相液相色谱柱分离,以电喷雾正离子模式,多反应模式(MRM)检测。草胺膦、草甘膦、氨甲基膦酸的质量浓度在0～20μg/L范围内均具有良好的线性,线性相关系数大于0.995,方法定量限为0.01 mg/kg。在不同茶叶基质中,0.01,0.025,0.05 mg/kg三水平的平均添加回收率为94.0%～116.0%,测定结果的相对标准偏差为3.5%～7.1%(n=6)。该方法操作简便,灵敏度与准确度高,满足茶叶样品中草胺膦、草甘膦及其代谢物氨甲基膦酸低残留的检测要求。     

柱前衍生化/毛细管电泳法测定阿伦膦酸钠

建立了一种以对甲氧基苯磺酰氯为紫外衍生试剂柱前衍生,毛细管电泳法测定阿伦膦酸钠的分析方法。阿伦膦酸钠与对甲氧基苯磺酰氯的衍生条件为:在20 mmol/L的硼酸盐缓冲溶液(pH 11.5)中,摩尔比为1:10的阿伦膦酸钠与对甲氧基苯磺酰氯在50℃下反应10 min。将衍生产物在毛细管电泳上进行分离,使用pH 9.3 20 mmoL/L的硼酸盐缓冲溶液为分离缓冲体系,柱温25℃,分离电压20 kV,在0.5 psi压力下进样5 s,以二级管阵列(DAD)检测器在233 nm处进行检测。测得阿伦膦酸钠的线性范围为1.0~400μg/mL,检出限为0.5~1.0μg/mL。方法用于药物制剂阿伦膦酸钠片和尿液介质中阿伦膦酸钠的测定,结果满意。     

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。     

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.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

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.     

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.     

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.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

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.