6-疏基嘌呤,硫唑嘌呤,8-氮杂鸟嘌呤的滤纸基质室温燐光法研究

建立了 6 巯基嘌呤、硫唑嘌呤和 8 氮杂鸟嘌呤 3种抗癌嘌呤化合物的滤纸基质室温光分析新方法。详细探讨了影响其室温光发射的各种因素。该方法的线性范围、检出限、精密度分别为 6 巯基嘌呤2 0～ 4 .0× 10 2 μmol/L ,1.3μmol/L ,4 .1% ;硫唑嘌呤 2 .0～ 6 .0× 10 2 μmol/L、1.2 μmol/L、3.8% ;8 氮杂鸟嘌呤1.1～ 2 .2× 10 2 μmol/L、7.4× 10 -2 μmol/L、1.3%。用该方法进行尿液中嘌呤化合物的回收测定 ,回收率为 96 .2 %～ 10 1.7% ;进行 6 MP在药片中的回收测定 ,回收率为 96 .2 %～ 10 2 .1%。     

流动注射化学发光增强法测定巯嘌呤的应用研究

试验发现6-巯基嘌呤对Luminol-H2O2-OH-体系的化学发光有较强的增敏作用。据此建立了一种流动注射化学发光增强法测定6-巯基嘌呤的新方法。该法测定6-巯基嘌呤的检出限为7.5×10-9mol/L,线性范围为2.0×10-8~2.5×10-6mol/L,对6.0×10-7mol/L的6-巯基嘌呤测定的相对标准偏差为1.6%(n=11),已用于合成样中6-巯基嘌呤的测定。     

钇(Ⅲ)-3-噻唑偶氮-5-氨基苯酚络合物的极谱络合吸附波研究

在pH 8.40的NH3-NH4Cl缓冲溶液中,钇与3-噻唑偶氮-5-氨基苯酚络合物有一灵敏的极谱吸附波,其峰电位在-0.67 V(vs.SCE),峰电流与钇的浓度在1×10-7~8×10-4mol/L之间呈线性关系,检出限为8×10-8mol/L;经多种电化学方法证明该波为络合物吸附波,其电极过程为不可逆过程,电子转移数为2,此外还试验了多种离子对峰电流的影响,所拟方法已用于茶叶中钇的测定。     

2-氨基-5-巯基-[1,3,4]三氮唑自组装膜电极对尿酸的电催化氧化及其分析应用

利用新合成的试剂2-氨基-5-巯基-[1,3,4]三氮唑在金电极上进行了自组装,对自组装电极进行了电化学和扫描电镜表征,研究了尿酸在该电极上的电化学行为。结果表明,尿酸在该电极上可被电催化氧化,方波伏安氧化峰电流与尿酸浓度在4.0×10-6～1.0×10-3mol/L范围内成分段线性关系,检出限为8.0×10-7mol/L。该电极能有效消除基体干扰,可用于对尿液样品中尿酸测定。     

毛细管电泳-电化学法对发芽黑米胚芽中γ-氨基丁酸含量的检测

采用邻苯二甲醛(OPA)为柱前衍生化试剂,用毛细管电泳-电化学检测的方法(CE-ED)测定发芽黑米胚芽中γ-氨基丁酸、缬氮酸和亮氨酸的含量.以直径为300μm的碳圆盘电极为工作电极,50mmol/L硼砂(pH 8.2)为运行缓冲液,对上述3种组分的分离检测条件进行优化研究.在优化条件下,3组分可在15min内完全分离.γ-氨基丁酸、缬氨酸和亮氨酸的线性范围分别为5.0×10-3～0.12、5.0×10-3～0.08和5.0×10-3～0.12g/L,检出限(S/N=3)分别为2.5×10-3、2.5×10-3、2.6×10-3g/L;7次平行进样峰高的相对标准偏差(RSD)分别为2.5%、4.9%、3.9%.     

巯嘌呤与铜的配合物的电化学研究

在0.1 mol/L的B-R底液(pH=4)中,用单扫描示波极谱法可以得到一个灵敏的6 巯基嘌呤与二价铜离子配合物的导数还原峰,其峰电位为-0.40 V(vs.SCE),其二阶导数波高与6 巯基嘌呤溶液在 4×10-7~1×10-5mol/L浓度范围内呈线性关系,检测限为 3×10-8 mol/L.该法可用于药物中 6 巯基嘌呤的测定,平均回收率为98 7%.对6 MP Cu2+在汞电极上的电化学行为特别是对其吸附性能进行了探讨.     

聚氨基-β-环糊精修饰电极对多巴胺电化学行为的研究

利用合成的6-氨基-6-脱氧--βCD在玻碳电极上制备聚合物膜(PACD),用循环伏安法研究PACD对多巴胺(DA)的电化学行为,实验结果显示,在pH 6.5的磷酸盐缓冲溶液中,氧化峰电流与多巴胺浓度在4×10-7~1.5×10-4mol/L范围内呈线性关系,相关系数达0.9921,检出限为2.3×10-7mol/L。     

氮掺杂石墨烯修饰电极的制备及对鸟嘌呤的电催化氧化

采用高温热退火方法制备了氮掺杂的石墨烯,并制备了氮掺杂石墨烯修饰玻碳电极(NG/GCE),研究其对鸟嘌呤的电催化氧化作用.实验考察了溶液pH值、扫速、鸟嘌呤浓度的影响.结果表明,鸟嘌呤在NG/GCE上的氧化是不可逆过程,修饰电极可以增强鸟嘌呤在电极表面的吸附,对鸟嘌呤具有很好的电催化氧化性能,降低了鸟嘌呤氧化电位.在pH=7.0的磷酸盐缓冲溶液中检测鸟嘌呤,其氧化峰电流在5.0×10-6～1.0×10-4 mol/L浓度范围内呈良好的线性关系,检出限(3σ)为1.0×10-6 mol/L.     

二维毛细管电泳电化学检测尿样中的β-阻断剂

设计并制作了在柱电化学(EC)检测池,用于在同一根毛细管中进行中心切割二维毛细管电泳(2D-CE)在线纯化分离检测尿样中的6种β-阻断剂.尿样先在15 mmol/L NaAc缓冲液中进行毛细管区带电泳(CZE)分离,带正电荷的β-阻断剂与中性和带负电荷的干扰物质分成不同区带,然后在检测端施加13.8 kPa压力将干扰成分从毛细管入口端排出,同时将目标组分驱送到毛细管入口端,最后在90 mmol/L NaAc-30 mmol/L SDS缓冲液中进行胶束电动毛细管色谱(MEKC)分离.场放大样品堆积(FASS)/胶束推扫在柱双重富集技术不仅有效抵消压力驱送过程中产生的区带扩散,还可进一步压缩样品区带,提高检测灵敏度.本方法成功用于服药后鼠尿样品中6种β-阻断剂的分离测定,经第一维CZE分离排除干扰后,在未涂层毛细管柱(60 cm ×50 μm i.d.)、90 mmol/L NaAc/HAc-30 mmol/L SDS运行缓冲液、检测电位0.8 V、运行电压10 kV条件下,对6种β-阻断剂进行在线富集分离,峰高、峰面积和迁移时间的相对标准偏差(RSD)分别为2.0%～4.1%, 1.4%～3.7%和0.9%～2.7%(n=6).本研究为毛细管电泳在复杂样品在线纯化分析等方面的应用提供了新方法.     

双通道-双工作电极毛细管电泳电化学法快速检测大黄酸

报道了一种测定大黄酸的快速毛细管电泳电化学方法。采用简易制作的一种双通道-双工作电极电化学系统,可以实现电导法和安培法同时检测;优化选择了缓冲介质、工作电极、检测电位、毛细管长度和内径以及分离电压等实验参数,并对提高分析速度进行了初步研究和探讨。结果表明:大黄酸在100s内可以得到较好的分离测定,电导法和安培法的线性范围分别为6.83×10-4～1.07×10-5mol/L和3.41×10-4～2.67×10-6mol/L,最小检出浓度分别为5.28×10-6mol/L和3.16×10-7mol/L。采用设计的双通道 双工作电极检测装置,可以充分发挥电导法和安培法的优越性,对样品峰及样品的纯度进行确证;另外通过采用较短的毛细管与适当提高分离电压,可以提高分析速度。该法已用于中药大黄中大黄酸的测定。     

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.