柱切换高效液相色谱法测定人血浆中布洛芬对映体浓度

建立了柱切换高效液相色谱法测定人血浆中布洛芬对映体浓度的方法。以对溴苯甲酸为内标,样品经醋酸钠缓冲液酸化后,用V(正己烷)∶V(异丙醇)=95∶5萃取。以Chiralcel OJ-H柱(Daicel Chemicals,250mm×4.6mm,5μm)为分析柱,UltimateTM SiO柱(50mm×4.6mm,5μm)为预处理柱;流动相为V(正己烷)∶V(异丙醇)∶V(三氟醋酸)=96.5∶3.5∶0.1,流速为0.5mL/min;预处理流动相为V(正己烷)∶V(异丙醇)=99.5∶1,流速为1mL/min;柱切换时间为1.70~4.09min;紫外检测波长为230nm。布洛芬消旋体和S-( )-布洛芬标准曲线线性范围分别为0.21~20mg/L和0.10~10mg/L;日内RSD小于6.5%,日间RSD小于6.1%;方法回收率为93.3%~107.1%,萃取回收率为80.0%~86.6%。本法简便、准确,重现性好,可用于布洛芬对映体人体药代动力学研究。     

高效液相色谱法测定方便面中丙烯酰胺

建立了一种检测方便面中丙烯酰胺的液相色谱方法。萃取剂选择1g/L的蚁酸溶液,将萃取液以12000r/min,2℃离心18min,上清液再以14500r/min,0℃离心18min,可分离基质中淀粉、蛋白质、脂肪等干扰物;方法采用ZORBAX SB-C18(250mm×4.6mm,5μm)色谱柱,流动相为A(乙腈∶水=1∶24(V/V))和B(乙腈),流速0.5mL/min,在丙烯酰胺的最大吸收197nm处检测,提高了方法的检出限及回收率。该方法有良好的线性关系(r=1.00000),检出限为48.0μg/kg。回收率94.4%～109.8%,相对标准偏差为4.9%～5.6%。     

全自动在线固相萃取-二维高效液相色谱与质谱联用测定辣椒油中苏丹红

建立了全自动在线固相萃取-二维高效液相色谱与质谱联用快速测定辣椒油中的苏丹红Ⅰ,Ⅱ,Ⅲ,Ⅳ的方法。样品经乙腈和二氯甲烷萃取后,在一维色谱柱(Acclaim PAⅡ,150 mm×3.0 mm×3μm)上分离出苏丹红,通过阀的分段切换,依次富集在SPE柱(Acclaim 120 C18,10 mm×4.6 mm×5μm)上,在线完成净化和萃取富集;再通过阀切换将它们转移至二维色谱流路,在Acclaim 120 C18色谱柱(100 mm×2.1 mm×2.2μm)上分离检测。一维色谱以水-乙腈-甲醇/四氢呋喃(1∶1,V/V)为流动相,进样体积20μL,0.6 mL/min流速梯度洗脱和紫外-可见检测器(λ=254 nm)监测分离状况;二维色谱以水-乙腈-甲酸/乙腈(1∶1000,V/V)为流动相,0.3 mL/min流速梯度洗脱,采用单四极质谱仪,选择离子方式检测。整个分析流程27 min即可完成。4种苏丹红的保留时间的相对标准偏差均小于0.1%,色谱峰面积的相对标准偏差均小于2%(n=7);在0.6～60μg/L范围内峰面积与进样质量浓度的线性相关系数均大于0.9958;加标回收率为50%～97%;方法检出限均小于0.2μg/L(S/N=3)。测定结果令人满意。     

离子液体[C_4 mim][PF_6]超声辅助萃取/LC-MS/MS法测定水中痕量溴敌隆及溴鼠灵

建立了离子液体超声辅助萃取/高效液相色谱-串联质谱联用测定水中溴敌隆和溴鼠灵的方法。采用疏水性离子液体1-丁基-3-甲基咪唑六氟磷酸盐[C4mim][PF6]萃取样品,考察了试样体积、pH值、温度、超声萃取时间和无机盐含量等因素对萃取效率的影响。待测物在XDB C18(150 mm×2.1 mm,5μm)色谱柱上,以甲醇-0.2%乙酸(85∶15)为流动相,电喷雾(ESI)电离负离子多反应监测模式(MRM)进行测定。在优化萃取条件下,溴敌隆和溴鼠灵在0.005~1.0μg·L-1范围内具有良好线性,相关系数(r)大于0.999,回收率为91.0%~97.8%,日内相对标准偏差为1.1%~6.6%,日间相对标准偏差为2.5%~9.1%,定量下限为0.005μg·L-1。建立的方法简便、干扰少、特异性强,可用于环境水样中痕量溴敌隆和溴鼠灵的测定。     

超声萃取高效液相色谱法检测土壤中烟嘧磺隆和莠去津的残留量

建立了一种从土壤中超声提取烟嘧磺隆和莠去津并采用高效液相色谱法检测其残留的分析方法。选用体积比为1∶2的乙腈和水作为萃取剂,对土壤样品进行超声萃取。使用ODS-BP Sino Chrom C18(4.6mm×200mm,5μm)色谱柱,以甲醇和水(加入体积比为0.8%的冰乙酸)为流动相,配比为62:38,在流速为1.0mL·min-1,紫外检测波长235nm条件下进行测定。实验结果表明:烟嘧磺隆质量浓度在7.96~79.68μg·mL~(-1)范围线性关系良好,相关系数为0.9998,变异系数为1.46%,平均回收率为97.05%;莠去津质量浓度在3.92~39.92μg·mL~(-1)范围线性关系良好,相关系数为0.9989,变异系数为0.72%,平均回收率为97.48%。此方法可快速检测土壤中烟嘧磺隆和莠去津的残留量,具有灵敏简单、节省有机溶剂等优点。     

加速溶剂萃取-QuEChERS/超高效液相色谱-串联质谱法同时测定药食同源性食品中双酚类化合物

建立了加速溶剂萃取(ASE)-QuEChERS/超高效液相色谱-串联质谱(UPLC-MS/MS)同时测定药食同源性食品中11种双酚类化合物残留的分析方法。样品经ASE萃取,萃取溶剂为乙腈-乙酸-水(89∶1∶10,体积比),萃取温度为80℃,静态萃取时间为6 min,循环2次。萃取液经QuEChERS法净化,采用ACQUITY UPLC HSS T3色谱柱(2.1 mm×100 mm,1.8μm)分离,以甲醇(含0.1%甲酸)和5 mmol/L乙酸铵水溶液(含0.1%甲酸)为流动相进行梯度洗脱,电喷雾电离源正、负模式下同时进行多反应监测(MRM)测定,同位素内标法定量。11种双酚类化合物在0.5～50.0μg/L范围内呈良好线性,相关系数(r²)不小于0.996 0,检出限为0.1～0.5μg/kg,定量下限为0.3～1.5μg/kg;3个加标水平的回收率为72.4%～108%,相对标准偏差(RSD)为1.7%～15%。该方法操作简单、快速、灵敏度高、重现性好,适用于药食同源性食品中双酚类化合物的同时快速测定。     

离子液体超声辅助萃取/LC-MS法测定环境水中痕量五氯酚

建立了离子液体超声辅助萃取/液相色谱-质谱联用测定环境水中痕量五氯酚(PCP)的方法。采用离子液体1-丁基-3-甲基咪唑六氟磷酸盐[C4mim][PF6]为萃取剂,考察了试样体积、p H值、温度、超声萃取时间和无机盐含量等因素对PCP萃取效率的影响,试样在XDB C18(150 mm×2.1 mm,5μm)色谱柱上,以甲醇-2 mmol/L醋酸铵溶液(70∶30)为流动相,电喷雾(ESI)电离负离子选择离子监测模式(SIM)进行测定。在优化的萃取条件下,PCP在0.005~1.0μg·L-1范围内具有良好线性,相关系数(r)为0.999 2,回收率为91.0%~97.0%,日内相对标准偏差(RSD)为1.1%~5.4%,日间RSD为3.8%~8.3%,定量下限为0.005μg·L-1。建立的方法简便、干扰少、特异性强,可用于环境水样中痕量PCP的测定。     

分子印迹固相萃取/高效液相色谱法测定猪肝中盐酸克伦特罗的方法研究

建立了分子印迹固相萃取/高效液相色谱法测定猪肝中盐酸克伦特罗残留量的方法。以ASB C18色谱柱(250 mm×4.60 mm,5μm)分离,流动相为甲醇-水(45∶55,p H 3.0),紫外检测波长243 nm,进样量10μL,流速0.6 m L/min,柱温30℃。分子印迹固相萃取条件为:上样溶剂为双蒸水,上样流速为0.6 m L/min;洗脱剂为1%三氟乙酸的甲醇溶液。上述优化条件下,该方法在0.432~4.32μg/m L范围内线性关系良好,相关系数(r)为0.999 0。加标回收率为84.7%~92.0%,相对标准偏差(RSD)为1.5%~1.8%。方法的准确度和精密度满足残留分析的要求。     

微波辅助萃取/高效液相色谱串联质谱法对山银花中活性成分含量的测定

建立了微波辅助萃取/高效液相色谱串联质谱法(MAE/HPLC-MS/MS)同时测定山银花中10种活性成分含量的方法。山银花药材采用MAE萃取,萃取溶剂为乙醇-水(7∶3),固液比1∶30,萃取温度70℃,萃取时间10 min。采用HPLC-MS/MS测定萃取液中活性成分的含量,色谱柱采用Agilent Poroshell120 SB-C18(100 mm×2.1 mm,2.7μm),以0.5%甲酸-乙腈为流动相进行梯度洗脱,负离子多重反应离子监测模式检测。在优化条件下,10种成分的定量分析在10 min内完成。结果表明,10种活性成分的线性范围为0.05～500 mg/L,相关系数(r)不低于0.996 9,检出限和定量下限分别在69～4 413μg/kg和231～14709μg/kg范围,回收率为94%～105%。采用该方法检测6个不同产地的山银花样品,10种活性成分的含量在3.98～14 356.31 mg/kg范围。该方法快速、准确,可有效地用于山银花药材的质量控制。     

高效液相色谱-质谱联用技术测定人血浆中双氢青蒿素的含量

建立了测定人血浆中的双氢青蒿素的液相色谱 -质谱联用法。色谱条件 :AlltimaC18 柱 (2.1×150mm ,5μm ,流动相 :甲醇 -水 (体积比85∶15) ;流速 :0.2mL/min ;柱温 :25℃ ;进样量 :20μL。质谱条件 :电喷雾离子源 (ESI) ;用于定量分析的离子分别为m/z307(双氢青蒿素) ,m/z275(蒿甲醚 )。样品用液 -液萃取方法处理。双氢青蒿素的线性范围为5～200μg·L -1,定量下限为5μg·L -1,日内、日间精密度 (RSD)均小于10 % ,萃取回收率在71.5 %～83.2 %之间 (n=5) ,分析方法回收率在98.4 %～101.9 %之间 (n=5)。本法操作简便、准确、灵敏度高 ,适用于双氢青蒿素的药代动力学研究     

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.