稳定同位素稀释离子色谱-三重四极杆质谱法测定血浆和尿液中的氟乙酸

建立了离子色谱-三重四极杆质谱测定血浆和尿液样品中氟乙酸（MFA）的方法。血浆样品经高氯酸超声提取,尿液样品经高氯酸酸化,血浆和尿液提取液在pH 0.5~1.0条件下用叔丁基甲醚（MTBE）萃取,萃取液经氮吹浓缩后溶于0.1%（v/v）氨水溶液。以Ionpac AS 19型阴离子色谱柱为分析柱,在线自动产生的氢氧化钾作为淋洗液进行梯度分离,柱流出液经阴离子抑制器抑制后进入质谱系统。采用电喷雾电离源,在负离子、多离子监测（MRM）模式下检测,¹³C₂-氟乙酸稳定同位素内标法定量。血浆和尿液样品中氟乙酸的平均加标回收率为96.2%~120%,相对标准偏差为1.1%~13.1%（n=6）,方法的检出限（S/N=3）分别为0.03 μg/L和0.1 μg/L。该法简单、灵敏、准确,可用于生物样品中氟乙酸的检测。     

亲水相互作用色谱-四极杆/静电场轨道阱高分辨质谱检测奶粉中的氟乙酸钠

基于亲水相互作用色谱-四极杆/静电场轨道阱高分辨质谱系统,建立了奶粉中氟乙酸钠的快速筛查和定量检测方法。奶粉样品用水溶解后经正己烷脱脂,用6 mol/L硫酸调节pH值,经乙腈提取后用亲水相互作用色谱-四极杆/静电场轨道阱高分辨质谱进行分析。结果表明,该方法在1~50 μg/kg范围内线性关系良好,定量限为1 μg/kg,平均回收率为85.5%~106%,相对标准偏差为5.20%~13.6%。该方法可用于配方奶粉、脱脂奶粉和乳清粉等奶粉产品中氟乙酸钠的快速筛查和定量分析。     

柱前衍生-高效液相色谱法测定生物检材中的氟乙酸钠

以α-溴苯乙酮酯为衍生化试剂,合成了α-氟乙酸苯乙酮酯(APFA)化合物,并以其为标准,建立了柱前衍生-高效液相色谱法测定生物检材中氟乙酸钠的方法。样品中的氟乙酸钠经酸化,丙酮-水(体积比4∶1)萃取,与α-溴苯乙酮衍生化后进行HPLC分析。色谱条件为:Hypersil ODS柱,乙腈-水(体积比50∶50)为流动相,紫外检测波长为254 nm。α-氟乙酸苯乙酮酯在1×10-5~1×10-2mol/L的浓度范围内与峰面积呈良好的线性关系,线性相关系数为0.999 4,生物样品空白添加实验的回收率为86%~93%,检出限为6.0μmol/L(S/N=3),相对标准偏差(RSD)小于3%。该方法灵敏度高、重复性好,适用于生物检材中氟乙酸钠的测定。     

快速溶剂萃取-离子色谱-质谱法测定人体血液、尿液中的氟乙酸

建立了快速溶剂萃取-离子色谱-质谱法测定人体血液、尿液中氟乙酸的方法。以去离子水为萃取溶剂，使用快速溶剂萃取仪处理血液和尿液样品，取上清液依次经超滤管和0.22μm水相针式滤膜净化，稀释50倍后进样检测。采用Ion Pac AS20离子色谱柱以15.0 mmol/L的KOH溶液为淋洗液进行等度淋洗，流出液通过抑制器后进入三重四极杆质谱，在负离子、多反应监测模式下检测，外标法定量。结果表明，氟乙酸在0.5～500.0μg/L范围内线性关系良好(r>0.999),检出限和定量限分别为0.14、0.47μg/L。氟乙酸在血液和尿液中的回收率分别为93.4%～95.8%、96.2%～98.4%,日内精密度分别为0.8%～1.6%、0.2%～1.0%,日间精密度分别为2.3%～3.8%、3.9%～6.9%。进一步考察发现该方法在血液、尿液中的基质效应较弱，分别为-7.4%、-3.0%。该法无需衍生化处理，简便高效，灵敏度高，重复性好，适用于人体血液、尿液中氟乙酸的快速检测。     

离子色谱法测定血液等样品中的氟乙酸钠

建立了离子色谱法测定血液样品中灭鼠剂氟乙酸钠的方法。在0.2 mL血液样品中加入1 mL纯水,然后用乙腈沉淀蛋白质,待蛋白沉降后取上清液经0.45 μm过滤头过滤,滤液注进离子色谱仪进行氟乙酸钠的定性和定量分析。色谱条件：色谱柱为Dionex Ion Pac AS11阴离子交换柱(250 mm×4 mm i.d.)及其相应的AG11保护柱(50 mm×4 mm i.d.),流动相为2.0 mmol/L Na2B4O7,微膜自再生阴离子抑制器,电导检测,25 μL定量进样环。氟乙酸钠在0.10~10.0 m     

荧光试剂柱前衍生高效液相色谱-荧光检测生物检材中的氟乙酸钠

建立了以4-溴甲基-7-甲氧基香豆素(BrMMC)为柱前荧光衍生试剂,反相高效液相色谱荧光检测(HPLC-FLD)生物检材中氟乙酸钠的分析方法。采用Hewlett Packard RP-18色谱柱,以甲醇-水(60/40,V/V)为流动相,流速1.0 mL/min,柱温26℃,荧光检测:eλx=319 nm,eλm=390 nm,进样量2μL。结果表明:该法在氟乙酸钠含量为0.1~20μg/mL范围内与其峰面积呈良好的线性关系,线性相关系数为0.9996,检出限(S/N=3)为5×10-10mol/mL,相对标准偏差(RSD)小于4%。本法用于中毒死亡者的血液样品及其它检材的测定,效果良好。     

微波促进水杨醛肟一锅法制备2-二氟甲氧基苯腈

以氯二氟乙酸钠为二氟甲基化试剂,碳酸钾为碱,实现了微波促进水杨醛肟一锅脱水成腈及二氟甲基化反应,以中等收率获得了8个2-二氟甲氧基苯腈类化合物,其中7个为新化合物.利用核磁共振波谱、红外光谱和高分辨质谱等手段对目标产物进行了表征.讨论了二氟甲基化试剂、碱和溶剂的种类、微波功率、反应温度和时间对反应的影响.确定了最优反应条件:含有不同取代基的水杨醛肟、氯二氟乙酸钠、碳酸钾和N,N-二甲基甲酰胺的摩尔比为1∶1.5∶1.5∶13,微波功率300 W,反应温度85℃,反应时间20 min.结合对比实验,提出了可能的反应机理.     

雪松烯的光氧化反应研究

以次甲基兰为光敏剂, 甲醇为溶剂, 用通氧光照产生的单重态氧与雪松烯反应,产物只有一种。用元素分析、红外光谱。核磁共振谱、质谱以及高压液相色谱等方法测定了产物的分子结构。并讨论了光氧化反应的动力学控制和立体效应。     

固相配位化学反应研究——ⅩⅩⅪ 一取代五氰合钴酸钾的热分解

钴氰配合物的合成、结构和催化性能巳有不少研究,但热稳定性方面还很少报道,本文用气相色谱和四极质谱研究了3个一取代五氰合钴酸钾配合物的热分解过程,对分解时放出的气体产物用色谱、质谱进行了跟踪检测,对应各阶段的固相产物分别用红外和X-衍射谱进行了标识。实验结果表明这类配合物的热稳定性次序为:     

2-N,N-二(2-氯乙基)胺基-6-烷氧甲基-1,3,2-氧氮磷杂环己烷-2-氧化物的制备与性质研究

本文报道了一系列通式为化合物的合成。所有产物的结构都经元素分析、~1H核磁共振谱及质谱证明。并用~(3I)P核磁共振谱和X光衍射分析方法,研究了化合物的构型与构象。对系列化合物的核磁共振及质谱特性进行了研究与讨论。     

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.     

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.     

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.     

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.     

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.     

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.