十二烷基苯磺酸钠-硫酸耐而蓝体系的共振瑞利散射光谱及其分析应用

提出了共振瑞利散射法(RRS)测定十二烷基苯磺酸钠(SDBS)的新方法。在pH为1.98～3.29的B-R缓冲溶液中,硫酸耐而蓝与SDBS结合生成离子缔合物,使溶液共振瑞利散射(RRS)增强,其最大散射峰位于760 nm,另在533 nm、400 nm有两个较弱的散射峰。SDBS的浓度在0.04～1.6 mg/L范围内,与RRS强度有良好的线性关系,对SDBS的检出限(3σ)达0.018 mg/L。研究了适宜的反应条件和影响因素,表明该方法灵敏、稳定。用于环境水样中阴离子表面活性剂含量的测定,回收率为95.9%～106.7%。     

三元缔合物以双波长共振瑞利散射测定药物中酒石酸美托洛尔

建立了一种快速、准确测定药物中酒石酸美托洛尔的双波长共振瑞利散射(DWORRS)新方法。在酸性Tris-盐酸介质中,刚果红与酒石酸美托洛尔及表面活性剂十六烷基三甲基溴化铵反应生成红色三元缔合物,使双波长共振瑞利散射显著增强并产生新的具有2个明显散射峰的共振瑞利散射(RRS)光谱,最大共振瑞利散射峰位于375 nm,另一共振瑞利散射峰位于515 nm,酒石酸美托洛尔在0.004~0.55 mg/L范围内与体系的RRS增强强度的绝对值(│△I_(RRS)│)呈线性关系,检出限为0.0032 mg/L(375 nm),0.0038 mg/L(515 nm)和0.0018 mg/L(DWO-RRS,375 nm+515 nm)。还探讨了RRS的光谱特征、适宜反应条件、反应机理及共存物质的影响。方法用于药物中酒石酸美托洛尔含量的测定,加标回收率为98.57%~102.1%,相对标准偏差为2.0%~2.5%。     

中性红与透明质酸钠相互作用的共振瑞利散射光谱及其分析应用

在pH 4.3～5.2的B-R缓冲溶液中,中性红与透明质酸钠作用形成离子缔合物时导致溶液共振瑞利散射(RRS)大大增强并产生新的RRS光谱,其最大散射峰位于328 nm处,另在605 nm处有一个较弱的散射峰.透明质酸钠质量浓度在0～2.5 mg/L范围内,与RRS强度有良好的线性关系.据此,建立了新的测定透明质酸钠的分析方法.该法的检出限(3σ)为25.9 ng/mL,并已用于滴眼液和化妆水中透明质酸钠的测定.     

盐酸吖啶黄-脱氧核糖核酸反应体系的共振瑞利散射及其应用

研究了盐酸吖啶黄与脱氧核糖核酸(DNA)之间的共振瑞利散射(RRS)增强作用,提出了共振瑞利散射技术测定核酸的方法。在pH 6.4的B-R缓冲溶液中,盐酸吖啶黄与脱氧核糖核酸结合使溶液共振瑞利散射强度增强,其最大散射峰位于505 nm处,而在330 nm波长处有一稍弱的散射峰。DNA质量浓度在0.04~0.80 mg.L-1范围内,与RRS强度呈线性关系,检出限(3S/N)为0.023 mg.L-1。应用于测定合成样品中DNA含量并测得回收率为98.0%~104.0%。初步探讨了反应机理,盐酸吖啶黄与DNA间的相互作用包含有静电引力、π-π堆积力。     

铁(Ⅲ)与脱氧核糖核酸作用的共振瑞利散射光谱研究

研究了Fe3 与脱氧核糖核酸(DNA)的共振瑞利散射(RRS)光谱和适宜的反应条件。实验结果表明,在pH2.20的Britton-Robinson缓冲溶液中,Fe3 与DNA自身的共振瑞利散射峰均较弱,但当二者发生静电作用形成缔合物后,体系的共振光散射峰增强,最大散射峰位于320.0 nm处。当Fe3 浓度为2.75×10-5mol/L时,在0~8.4 mg/L范围内,共振光散射强度与DNA的浓度呈线性关系。检出限为2.60μg/L。据此建立了一种定量测定DNA的简便、快速的新方法。本方法用于合成样品中痕量DNA的测定,回收率为93%~101%。     

灿烂绿共振瑞利散射法测定药物及尿样中利福平的含量

建立了测定利福平的共振瑞利散射法。在弱碱性Tris-盐酸缓冲介质中,灿烂绿与利福平反应生成的络合物使共振瑞利散射急剧增强并产生新的RRS光谱,在291 nm处产生最大散射峰,利福平的质量浓度在0.16～0.99 mg/L范围内与共振散射强度(△IRRS)呈线性关系,线性回归方程为△IRRS=-12.61+2620ρ,相关系数为0.9997,检出限(3Sb/K)为0.014 mg/L。方法可用于市售利福平药物及尿样中利福平含量的测定,结果满意。     

乙基紫作光谱探针共振瑞利散射光谱测定硫酸皮肤素

在pH5.5～6.5的Britton-Robinson缓冲溶液中,乙基紫与硫酸皮肤素作用形成结合产物时将导致溶液共振瑞利散射(RRS)显著增强并产生新的RRS光谱,其最大散射峰位于498 nm处,另在327 nm和650 nm处有两个强度较小的散射峰.硫酸皮肤素浓度在0～1.6 mg/L范围内,与RRS强度有良好的线性关系.据此,建立了一种测定硫酸皮肤素的分析方法.该法具有高灵敏度,对硫酸皮肤素的检出限为5.0 ng/mL,选择性良好.应用于尿样和血清中硫酸皮肤素的测定,结果令人满意.     

硫酸卡那霉素-固绿体系的共振瑞利散射光谱及其分析应用

提出了共振瑞利散射法(RRS)测定硫酸卡那霉素(KANA)的方法。在p H为4.56~6.09的B-R缓冲溶液中,固绿与KANA结合生成离子缔合物,使溶液共振瑞利散射(RRS)增强,其最大散射峰位于709 nm,另在463 nm、370 nm有两个较弱的散射峰。KANA的浓度在0.08~1.6 mg·L~(-1)范围内,与RRS强度有良好的线性关系,对KANA的检出限(3σ)达0.024 mg·L~(-1)。研究了适宜的反应条件和影响因素,表明该方法灵敏、稳定。用于硫酸卡那霉素注射液的测定,回收率为96.5%~103.0%。     

健那绿作光谱探针共振瑞利散射法测定藻酸钠

本文提出了共振瑞利散射法测定藻酸钠的新方法。研究发现在pH=4.0的Britton-Robinson缓冲溶液中,藻酸钠或健那绿单独存在时共振瑞利散射(RRS)强度非常弱,当两者反应形成复合物时,RRS大大增强并产生新的RRS光谱,其最大RRS峰位于560nm,另在328nm和397nm处产生两个强度较低的散射峰。在560nm处,藻酸钠的浓度在0.015～1.0μg/mL范围内与RRS强度有良好的线性关系,检出限(3σ/k)为5ng/mL。方法灵敏度高,选择性好,可用于面条和海带提取液中的藻酸钠测定。     

乙基紫探针共振瑞利散射法测定头孢硫脒

建立了测定痕量头孢硫脒(CEFA)的共振瑞利散射(RRS)法。在稀NaOH溶液中,头孢硫脒与乙基紫(EV)结合,使体系的RRS急剧增强并产生新的RRS光谱,最大共振光散射峰位于波长341nm处,头孢硫脒的质量浓度在0.094~0.70mg/L范围与散射强度(△IRRS)呈良好的线性关系,检出限(3Sb/K)为0.075mg/L。该方法可用于人体血液及市售药物中头孢硫脒的测定。     

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.