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。     

曙红B-蛋白质-聚乙烯醇体系显色反应及其分析应用

用分光光度法研究了曙红B(EB)与牛血清白蛋白(BSA)在聚乙烯醇(PVA)存在时的结合反应 ;在最佳反应条件下 ,以试剂空白参比 ,EB -BSA复合物的最大吸收波长在538nm ,BSA的浓度在1.6×10-8～2.8×10-7 mol·L-1 范围符合比尔定律 ,表观摩尔吸光系数ε=1.41×106 L·mol-1·cm-1,Sandell灵敏度s=0.048μg·cm -2 ,对BSA的检出限为4.9×10 -9mol·L -1 ,方法用于人血清中蛋白质总量的测定 ,与经典的考马斯亮蓝G_250方法结果一致     

盐酸氯丙嗪-卤代荧光素体系的光度法测定

在NaAc HCl缓冲介质中,盐酸氯丙嗪可与曙红Y、赤藓红、乙基署红等卤代荧光素染料反应,形成离子缔合物,溶液颜色发生明显改变,可用光度法测定。盐酸氯丙嗪的浓度在0～1.6×10-5mol·L-1(曙红Y)、0～1.3×10-5mol·L-1(赤鲜红)、0～1.5×10-5mol·L-1(乙基曙红)范围内遵守比耳定律,其表观摩尔吸光系数分别为4.63×104L·mol-1·cm-1、2.50×104L·mol-1·cm-1、为4.32×104L·mol-1·cm-1。方法用于片剂和针剂中盐酸氯丙嗪的测定,结果满意。     

蛋白质固体表面荧光分析法研究

本文以滤纸为基质研究曙红Y与牛血清蛋(BSA)白作用,建立了蛋白质的固体表面荧光分析法。实验证明,本方法具有操作简便、灵敏度高(检出限0.15mg·L-1)、线性范围宽(0.15～50mg·L-1)、取样量少(6μL/spot)等特点,对合成样品中的牛血清蛋白(BSA)测定结果令人满意。     

曙红Y褪色光度法测定微量铈

研究了在氨-氯化铵介质中Ce(Ⅳ)催化高碘酸钾氧化曙红Y的褪色反应及其动力学条件,测定了反应级数和表观活化能,建立了测定痕量铈的新方法.曙红Y的最大吸收波长为515 nm,该方法的检出极限为2.0×10-10 g·ml-1,线性范围为0～400 ng·ml-1,可用于发样中痕量铈的测定.     

人血清白蛋白荧光猝灭法测定苏丹红Ⅰ

研究了在0.1 mol·L-1 Tris-HCl缓冲溶液(pH 8.2)中,人血清白蛋白(HSA)的荧光性质以及由于苏丹红Ⅰ的存在而使HSA的荧光猝灭现象进行了研究.结果表明:当HSA溶液在280 nm波长激发时,其发射波长为337 nm.当有苏丹红Ⅰ存在时其荧光发射的强度将出现猝灭,而且荧光猝灭程度(△F)与苏丹红Ⅰ的质量浓度在0.5～7.5 mg·L-1(r=0.999 7)之间呈线性关系,方法的检出限(3Sb/k)为0.1 mg·L-1,测定限(10Sb/k)为0.5 mg·L-1,相对标准偏差(m=6,n=11)为0.7%～1.8%,加标回收率为91.9%～109.3%.     

曙红Y分光光度法测定盐酸异丙嗪

在弱酸性NaAc HCl缓冲介质中 ,盐酸异丙嗪与曙红Y、赤藓红、乙基曙红等卤代荧光素类染料反应 ,形成离子缔合物。溶液颜色发生明显变化 ,其中曙红Y体系则发生显著的褪色作用 ,最大褪色波长为 5 16nm ,ε为 2 .73× 10 4 L·mol- 1 ·cm- 1 ,此外在 5 4 8nm处出现一个较低的吸收峰 (Δλ =32nm)。因此 ,本文采用曙红Y褪色光度法测定盐酸异丙嗪。其浓度在 0～ 1.5× 10 - 5mol/L范围内遵守比尔定律。方法灵敏度较高 ,选择性好 ,操作简便快速。用于片剂、针剂和伤风止咳糖浆中盐酸异丙嗪的测定 ,结果满意。     

FAAS法测定青梅酒和干红葡萄酒中铁

铁是人体必需的微量元素,但若摄入过量,也会对人体健康造成危害。本文采用火焰原子吸收光谱法直接测定青梅酒和红葡萄酒中铁,检出限为0·019 8 mg·L-1,回收率为93.8%~107.0%。1试验部分1.1主要仪器与试剂PE-100型原子吸收分光光度计铁标准储备液:1.000 0 g·L-1,使用时稀释为10.0 mg·L-1。试剂均为优级纯1.2仪器测定条件波长248.3 nm,灯电流23 mA,光谱通带宽度0.2 nm,空气流量5 L·min-1,乙炔流量0·5 L·min-1。1.3试验方法吸取铁标准溶液0.00,0.50,1.25,2.50,3.75,5.00 mL于25 mL比色管中,加入乙醇0.5 mL,用2.0 moL·L-1硝酸稀至…     

Zn（Ⅱ）—锌试剂络合物与蛋白质的显色反应及其应用研究

在 pH 2 .8的氯乙酸缓冲溶液中 ,有TritonX 10 0存在下 ,Zn(Ⅱ ) 锌试剂络合物与蛋白质结合生成玫瑰红色复合物 ,最大吸收波长在 32 8nm ,蛋白质浓度在 0～ 8.0及 10 .0～ 130 .0mg·L- 1范围符合比耳定律 ,复合物的表观摩尔吸光系数分别为 2 .31× 10 5和 6.63× 10 5L·mol- 1·cm- 1。方法用于麦片、花生、豆类及牛奶中蛋白质的测定 ,结果满意     

偶氮氯膦Ⅲ吸光光度法测定水中微量钙

探讨了偶氮氯膦Ⅲ吸光光度法测定水中微量钙的最佳测定条件。试验表明,在pH2 80～2.85柠檬酸三钠 盐酸缓冲溶液中,钙离子与偶氮氯膦Ⅲ形成1∶1的配合物,其吸收峰为双峰,最大吸收波长为666nm,水中钙离子含量在0～0.56mg·L-1范围内符合比耳定律,回归方程C=0.0013+2.6382A(mg·L-1),相关系数为0.9999,摩尔吸光系数ε=1.54×104L·mol-1·cm-1,加入EDTA或葡萄糖酸钠等掩蔽剂后,其他金属阳离子在测定条件下对钙离子的测定基本无影响。     

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.