乙基曙红光度法测定西地那非的含量

在pH3.5～4.0的NaAc HCl缓冲介质中,西地那非与乙基曙红反应,形成离子缔合物,使乙基曙红溶液颜色发生明显改变,最大吸收波长在550nm,比乙基曙红红移了30nm,并在520nm处产生最大褪色作用,从而建立测定西地那非(Sild)的光度法。在最大褪色波长520nm处,西地那非浓度在0.2～2.0×10-5mol·L-1范围内遵守比耳定律,表观摩尔吸光系数ε520为2.44×104L·mol-1·cm-1,检出限为9.3×10-7mol·L-1,若用双波长叠加,则表观摩尔吸光系数ε520+550达4.53×104L·mol-1·cm-1,检出限达5.0×10-7mol·L-1。本法操作简便,体系稳定,灵敏度较高,选择性好,用于柠檬酸西地那非片(万艾可)中西地那非含量的测定,结果满意。     

离子对缔合物萃取分光光度法测定维生素K3

研究了维生素K3 (vitaminK3, VK3)与碱性染料丁基罗丹明B(butyl rhodamine B, BRB)、乙基紫( ethyl violet, EV)和亚甲基蓝(methylene blue, MB)形成离子对缔合物的反应,确定了反应的最佳条件.建立了测定VK3含量的简单、快速、选择性好和灵敏度高的分析方法.VK3与BRB、EV及MB反应生成可被有机溶剂萃取的离子对缔合物,离子对缔合物分别在568、613 和658 nm处有最大吸收,其表观摩尔系数分别为2.92×104 、6.96×104和4.85×104 L·mol-1·cm-1;离子对缔合物的组成均为11, 稳定常数分别是9.5×105、1.9×106和7.8×105; 药物浓度分别在0.0083～13、0.029～6.6和0.015～9.6 mg/L范围内符合比尔定律;回收率为96%～103%.该法可成功地用于药物制剂中VK3含量的测定.     

镧-曲利本红光度法测定新霉素及庆大霉素

在pH3.0～6.5的条件下,镧(Ⅲ) 曲利本红(TR)与硫酸新霉素(NEO)或硫酸庆大霉素(GEN)反应生成三元红色离子缔合物,其最大吸收波长位于388nm,摩尔吸收光系数(ε)为4.86×104、2.10×104L·mol-1·cm-1;最大负吸收波长位于432nm(NEO)和428nm(GEN),摩尔吸收光系数(ε)为1.38×104、1.19×104L·mol-1·cm-1。当用双波长叠加时,ε值为6.24×104(NEO)、3.28×104(GEN)L·mol-1·cm-1。探讨了适宜的反应条件和主要分析化学性质。该法用于市售药物中新霉素、庆大霉素含量的测定,结果满意。     

镧-滂胺天蓝光度法测定人血清及尿样中的几种抗生素

在pH 2 .8～ 6 .5的条件下 ,镧 和 6 ,6′ (2 ,2′ -二甲氧基 4 ,4′ -亚联苯基双偶氮 )二 (5 羟基 4 氨基 1 ,3 萘二磺酸钠 ) (滂胺开蒸 ,PSB)与硫酸新霉素 (NEO)、硫酸庆大霉素 (GEN)、硫酸卡那霉素 (KANA)反应生成具有明显显色峰和褪色峰的三元蓝色离子缔合物。其最大显色波长位于 6 88nm ,线性范围从 0～ 1 2 .0mg/L至 0～ 1 4 .0mg/L ,摩尔吸收光系数 (ε)在 3.0 8× 1 0 4～ 4 .6 4× 1 0 4L·mol-1 ·cm-1 之间 ;最大褪色波长在6 1 8～ 6 2 4nm之间 ,线性范围从 0～ 1 2 .0mg/L至 0～ 1 5 .0mg/L ,摩尔吸光系数 (ε)在 4 .4 3× 1 0 4～ 1 .1 3× 1 0 5L·mol-1 ·cm-1 之间。探讨了适宜的反应条件、主要分析化学性质及三元缔合物的络合比。该法用于人血清及尿样中新霉素、卡那霉素及庆大霉素含量的测定 ,结果满意     

水溶苯胺蓝褪色光度法测定庆大霉素及妥布霉素的研究

在酸性条件下,水溶苯胺蓝(ABWS)与硫酸庆大霉素(GEN)或硫酸妥布霉素(TOB)反应,生成离子缔合物,使水溶苯胺蓝溶液褪色,其最大褪色波长分别位于606nm(GEN)和608nm(TOB);在0～1.2×10-5mol·L-1(GEN)和0～1.5×10-5mol·L-1(TOB)的浓度范围内遵从比耳定律;表观摩尔吸光系数(ε)分别为2.21×104L·mol-1·cm-1(GEN)和3.10×104(TOB)L·mol-1·cm-1。本法已用于市售药物及人体尿液中庆大霉素及妥布霉素含量的测定,结果满意。     

新试剂二(2，4-二硝基苯肼)缩乙二醛的合成及应用-废水中溴化十六烷基三甲铵的测定

合成了新试剂二 (2 ,4-二硝基苯肼 )缩乙二醛 (GDPH) ,在氢氧化钠碱性介质中 ,该试剂与十六烷基三甲铵 (CTMAB)形成 1∶ 2的深蓝色离子缔合物。该缔合物的 λmax位于 630 nm,表观摩尔吸光系数为 3.6× 1 0 4 L· mol-1· cm-1,CTMAB的含量在 0～ 1 0 0 mg· L-1范围内符合比尔定律。使用此体系和高灵敏手持式光度计进行废水中 CTMAB的现场测定。     

丁基罗丹明B-碲钼杂多酸缔合显色反应的研究

本文研究了在聚乙烯醇(PVA)存在下,丁基罗丹明B(BRB)与碲钼杂多酸的离子缔合显色反应,碲钼杂多酸在0.025～0.075 mol/L硫酸溶液中形成丁基罗丹明B-碲钼杂多酸离子缔合物。形成酸度为1.26～2.16 mol/L硫酸,钼酸铵、丁基罗丹明B及PVA的适宜条件分别4.6×10~(-3)mol/,5.3×10~(-5) mol/L和0.16％。缔合物最大吸收波长为570 nm,表观摩尔吸光系数ε值为3.2×10~5 L·mol~(-1)·cm~(-1),符合比耳定律范围0～16μg Te/25ml。探讨了反应机理,用平衡移动法确定缔合物的摩尔比为Te:Mo:BRB=1:7:2,缔合物的可能化学式为(BRB)_2[TeMo_7O_(24)]。方法已用于烟尘中碲的测定,结果满意。     

水中阴离子表面活性剂的吸附分光光度法测定

研究萘基二苯甲烷与阴离子表面活性剂的缔合反应及缔合物在聚合物颗粒表面的吸附及洗脱 ,提出了碱性艳蓝BO分光光度法测定河水中的阴离子表面活性剂 ;碱性艳蓝BO与十二烷基苯磺酸钠、十二烷基硫酸钠、十二烷基磺酸钠的缔合物的表观摩尔吸光系数分别为3.76×104、3.63×104、2.15×104L·mol -1·cm -1 ,方法的线性范围为0.0～2.0mg/L,相对标准偏差3.8% (n=8);应用该法测定河水中阴离子表面活性剂含量 ,结果令人满意     

分光光度法测定高纯氧化铝中的二氧化硅

在含有明胶聚乙烯醇 (PVA)和草酸的 0 .0 1 2～ 0 .0 60 mol/L 盐酸介质中 ,罗丹明 B(RB)与硅钼杂多酸能形成离子缔合物 ,发生高灵敏显色反应 ,缔合物在 585nm处的表观摩尔吸光系数ε=1 .8× 1 0 5L· mol-1· cm-1,缔合物可稳定 2 4 h以上 ,此法已用于测定高纯氧化铝中的二氧化硅     

新型PVC膜涂丝诺氟沙星选择电极的研制与应用

制备了一种稳定性和重现性均良好的新型PVC膜涂丝诺氟沙星选择电极 ,该电极是以Ag/AgCl丝为基体 ,在其表面先涂一层含Cl-的脲醛树脂 ,然后再涂一层含硅钨酸 -诺氟沙星离子缔合物的PVC膜。采用正交设计法 ,研究了离子缔合物的种类、活性物在膜中的含量及增塑剂3因素对电极的影响。电极的线性范围为7.9×10 -5～1.0×10 -2mol·L -1 ,检出限为2.5×10 -5mol·L -1,斜率为35.7mV/decade(30℃) ,可直接用于诺氟沙星胶囊的含量测定 ,回收率为99 %～102 % ,结果与中国药典法基本一致。     

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.