流动注射-鲁米诺-铁氰化钾反应体系化学发光法测定依诺沙星

试验发现依诺沙星对鲁米诺与铁氰化钾之间的化学发光反应具有显著的增敏作用,而且当依诺沙星浓度在2.0×10-8～2.0×10-5mol·L-1范围内,与相应的化学发光增强信号值(△I)之间呈线性关系,其检出限(3S)为5.7×10-9mol·L-1,取1.0 × 10-6mol·L-1依诺沙星按试验方法测定11次,算得其相对标准偏差为1.75%.结合应用流动注射技术,提出了流动注射-化学发光法(FI-CL)测定药片中依诺沙星的方法,应用此方法分析了3个依诺沙星片剂试样,所测得的结果与其标示值相符.按标准加入法作了回收率试验,所得结果在96.7%～103.0%之间.     

流动注射化学发光法测定哈西奈德

试验发现,肾上皮质激素药物哈西奈德对鲁米诺与N-溴代丁二酰亚胺(BSMD)在碳酸钠一碳酸氢钠缓冲介质中反应所产生的化学发光(CL)有明显增强作用,且其增强程度与此药物的质量浓度在1.0×10-6～1.0×10-4g·L-1之间呈线性关系,检出限(3S/N)为3×10-7g·L-1.根据上述结果并结合应用流动注射技术,提出了测定哈西奈德的流动注射化学发光方法.在浓度水平为4.0×10-5g·L-1条件下,按方法作11次平行试验,求得其相对标准偏差为3.0%.应用此法分析了3个哈西奈德药物的实样,并用药典方法进行对照试验.结果表明:两方法所得结果相符.     

鲁米诺-铁氰化钾化学发光体系对盐酸环丙沙星的测定

环丙沙星对NaOH介质中的鲁米诺-铁氰化钾的化学发光具有较强的增敏作用,据此建立了一种新的测定痕量环丙沙星药物的流动注射化学发光法。讨论了介质浓度、发光试剂浓度等因素的影响,在最佳实验条件下,环丙沙星的质量浓度在2.0×10-5~1.2×10-4g.L-1范围内与发光强度呈良好线性关系,检出限为1.2×10-6g.L-1,11次平行测定4.0×10-5g.L-1环丙沙星的相对标准偏差为3.2%。该方法已用于环丙沙星片剂的测定,所得结果与标示值相符。     

固定HRP酶的聚苯乙烯整体微柱在VC含量测定中的应用研究

结合整体微柱和固定酶技术,以自制的苯乙烯整体微柱构建了一种固定辣根过氧化物酶(horseradish peroxidase,HRP)的整体微柱,确立了HRP的最佳固定条件,并用于蔬菜中维生素C(vitamin C,VC)含量的测定.采用碱性的Luminol-HRP-H2O2化学发光体系测定VC含量,在6 mg·L-1HRP酶和0.2 mL·min-1过柱速率下,VC浓度在1.0×10-9 ～1.0×10-7 mol·L-1范围内与化学发光强度呈良好的线性关系,检出限为1.76×10-7 g·L-1,相对标准偏差为3.57%,建立的固定HRP酶的整体微柱-化学发光检测方法可用于蔬菜中VC含量的测定,测定结果与经典碘量法所得数据一致,经加标回收法测得VC的回收率为98% ～103%.     

流动注射化学发光法测定工业废水中苯酚

采用流动注射技术,研究了高锰酸钾-过氧化氢-苯酚的化学发光行为,对影响化学发光强度的因素进行了试验,建立了流动注射化学发光法测定苯酚的方法。方法的检出限为3×10-5g.L-1,线性范围为1.0×10-4~1.0×10-1g.L,对浓度为4.0×10-4g.L的苯酚作试验,求得其相对标准偏差(n=11)值为1.6%。方法用于废水中苯酚含量的测定,结果与分光光度法测得值一致。     

三联吡啶合亚钌-亚硫酸根-氯酸钾体系化学发光法测定白葡萄酒中总亚硫酸盐

试验发现,亚硫酸根与氯酸钾及Ru(Ⅱ)与α,α'-联吡啶的络合物,Ru(Bipy)32 在SDBS存在下反应所产生的化学发光强度与亚硫酸根的浓度在1.0×10-7～1.0×10-4mol·L-1范围内呈线性关系,其检出限(3S/N)为9.26×10-8mol·L-1,对浓度为1.0×10-4mol.L-1亚硫酸根溶液重复6次测定,相对标准偏差为3.2%.该方法测定白葡萄酒中的总亚硫酸盐含量为3.384×10-5mol·L-1.并以此为基体加入3种不同浓度的亚硫酸根标准溶液作回收试验,测得回收率在96.8%～102.2%之间.     

流动注射化学发光法测定硫离子

在0.06 mol.L-1硫酸介质中,溴酸钾氧化鲁米诺产生化学发光,硫离子对这一体系的化学发光具有增强作用。据此,结合流动注射技术,提出了一种测定硫离子的方法。线性范围为1.0×10-6～1.0×10-3g.L-1(分为3个浓度区间),检出限(3s/b)为8.0×10-7g.L-1。对1.0×10-4g.L-1硫离子标准溶液进行平行测定,其相对标准偏差(n=11)为3.4%。该方法用于水样中硫离子的测定,并以此样品为基体做回收试验,测得回收率在96.5%～105.0%之间。     

流动注射-化学发光法测定扑热息痛

基于在0.5mol.L-1氢氧化钠介质中,扑热息痛对鲁米诺-过氧化氢体系的化学发光具有显著的抑制作用,提出了流动注射-化学发光法测定扑热息痛含量的方法。在优化的试验条件下,扑热息痛的化学发光强度与其质量浓度在4.5×10-5～1.5×10-2g.L-1范围内呈线性关系,方法的检出限(3σ)为9.0×10-7 g.L-1。此法用于扑热息痛片的分析,测得加标回收率在93.3%～106.7%之间,测定值的相对标准偏差(n=6)在2.6%～3.0%之间。     

流动注射-化学发光法测定药物中氢溴酸右美沙芬

试验发现由氢溴酸右美沙芬(D-MPHB)与高锰酸钾在5.0 mmol·L-1硫酸介质中反应所产生的较弱的化学发光强度因一定量的亚硫酸钠的存在而明显增强,且其化学发光的相对强度与D-MPHB浓度在1.0×10-5～1.0×10-1·L-1范围内呈线性关系,检出限(3S/N)为3.5×10-6g·L-1,根据这些结果并应用流动注射技术,提出了FI-CL法测定药物中氢溴酸右美沙芬的方法.应用所提出的方法分析了一种氢溴酸右美沙芬滴鼻液,测得其中D-MPHB的含量与标准值相符.以此药物为基体对方法的精密度及回收率作了试验,测得其相对标准偏差(n=5)均小于1.5%,回收率在99.7%～102.8%之间.     

流动注射-化学发光法测定苄青霉素

试验发现在5×10-3mol·L-1氢氧化钠溶液的碱性介质中,由高碘酸钾与鲁米诺之间的氧化还原反应所产生的化学发光的强度因苄青霉素的存在而明显增强,且其增强程度与苄青霉素的浓度在0.01～15.0 mg·L-1范围内呈线性,方法的检出限(3σ)为1.0μg·L-1,基于此并应用了流动注射技术,提出了一种简便而快速的测定苄青霉素的方法.加入1.0 mg·L-1的苄青霉素标准溶液对此方法的精密度做了试验,测得其相对标准偏差(n=11)为1.0%.在3件针剂样品的基础上加入了3种不同浓度的苄青霉素标准溶液,对方法的回收率做了试验,所得结果在97.2%～102.0%之间.     

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.