碘-溴化十六烷基三甲铵缔合体系溶剂浮选褪色光度法测定SO32-的研究

提出了碘 溴化十六烷基三甲胺缔合体系浮选褪色光度法测定SO3方法,方法的摩尔吸光系数为ε365=3.0×105L·mol-1·cm-1,最大吸收波长λmax2-0.10μg mL6次,RSD=1.8%,线性范围0～0 60μg mL,实=365nm,测定SO32-的质量分数。际测定了蔬菜中SO3     

5-碘[杯(4)芳烃偶氮]氨基喹啉光度法测钯

合成了新试剂5 碘[杯(4)芳烃偶氮]氨基喹啉(ICAQ),并研究了该试剂与钯显色反应条件。结果表明,在pH10.2～11.0的Na2CO3 NaHCO3缓冲介质中,在TritonX 100存在下,试剂与钯发生显色反应,生成1∶1稳定络合物。建立了测定钯的光度法新体系,λmax=625nm,ε=1.42×105L·mol-1·cm-1,钯质量浓度在0～0 80μg/mL内符合比尔定律。方法用于钯催化剂中钯的测定,结果与原子吸收法相符,平行6次测定的RSD在2.5%～3.0%。     

偶氮胂羧-Ce(Ⅲ)-HSA-OP的结合反应及其光度分析应用

偶氮胂羧在pH 3.85的HAc-NaAc缓冲介质中与Ce3+反应生成稳定的蓝紫色配合物,该配合物与生物大分子蛋白质反应形成蓝色复合物,λmax=702nm,比试剂本身的λmax=543 nm红移159 nm,ε=3.74×105L·mol-1·cm-1(HSA),蛋白质在0～90μg/mL范围内遵循比尔定律,加入表面...     

正交试验设计法研究DApMM试剂与锰(Ⅳ)的显色反应

以正交试验设计法研究了二安替比林对甲氧基苯基甲烷(DApMM)试剂吸光光度法测定微量锰的最佳显色体系。最大吸收波长λmax=450nm,摩尔吸光系数ε=6.82×104L·mol-1·cm-1。锰的质量浓度在0～2 0μg mL内符合比尔定律,方法已用于铝合金中锰的测定。     

磺基水杨酸-溴邻苯三酚红-溴化十六烷基吡啶分光光度法测定食品中钼的研究

研究了在pH5.6的HAc NaAc缓冲溶液中,溴化十六烷基吡啶(CPB)存在下,钼(Ⅵ)与溴邻苯三酚红及磺基水杨酸形成多元配合物的显色反应,建立了测定食品中微量钼的新方法。该配合物的最大吸收波长为λmax=620nm,表观摩尔吸光系数ε620=1.84×105L·mol-1·cm-1。钼(Ⅵ)浓度在0～0 80μg mL范围内符合比尔定律。应用于粮食作物中微量钼的测定,相对标准偏差小于4 8%,回收率为95.2%～100.5%。     

食品中添加剂甘氨酸的比色分析

研究了甘氨酸与乙酰丙酮-甲醛试剂显色反应的最佳条件、反应机理及共存物质的影响等。开发出食品中添加剂甘氨酸的比色分析方法。在pH6.5乙酸盐介质中,显色产物的λ_(max)为415nm,甘氨酸含量在0～200ug/10mL范围内符合比尔关系,摩尔吸光系数ε为2.3×10~3L/mol·cm。     

5‘—硝基水杨基荧光酮分光光度法测定微量铬（Ⅵ）的研究

本文研究了新显色剂5-硝基水杨基荧光酮(5-NSF)在阳离子表面活性剂溴化十六烷基三甲铵(CTMAB)存在下与铬()的显色反应。在pH5.5～6.7的磷酸盐缓冲介质中,Cr()与5-NSF反应生成组成比为1 4的水溶性和稳定性皆佳的紫色配合物,吸收峰波长λmax=586nm,对比度△λ=63nm,表观摩尔吸光系数586=1.74×105L·mol-1·cm-1,桑德尔灵敏度是3.0×10-4μg·cm-2,Cr()浓度为0～0.21μg/mL时服从比尔定律。采用阴离子交换树脂分离,能够消除许多金属离子的干扰。方法用于水样中微量总铬、Cr()和Cr()的测定,结果较满意     

5-碘[杯(4)芳烃偶氮]氨基喹啉光度法测钴

合成了新试剂 5 碘 [杯 (4 )芳烃偶氮 ]氨基喹啉 (ICAQ) ,并研究了该试剂与钴显色反应条件。在弱碱性介质中 ,不加任何辅助试剂 ,ICAQ与钴发生显色反应 ,生成 1∶1稳定络合物。λmax=61 5nm ,ε=4.78× 1 0 5L·mol- 1 ·cm- 1 ;钴含量在 1 0～ 1 3 0 μg L内符合比尔定律。方法用于维生素B1 2 、茶叶、水样中微量钴的测定 ,结果令人满意。     

碘-淀粉体系褪色光度法检测美白霜中对苯二酚

建立了基于碘-淀粉体系的褪色分光光度法,用于检测美白霜中对苯二酚的含量。碘能被捕获到直链淀粉螺旋状结构中,形成碘-淀粉蓝色复合物,在波长578 nm有最大吸收峰。当存在对苯二酚时,碘和对苯二酚发生氧化还原反应,碘被还原为碘离子,碘-淀粉体系蓝色变浅。建立波长578 nm的吸光度降低值与浓度的线性关系,确定对苯二酚的含量和检出限。对反应条件进行了优化,结果表明,在最佳实验条件(反应介质pH为2,氧化还原反应时间为30 min, 1×10^-3 mol·L^-1碘标准溶液用量为0.8 mL,0.5%淀粉溶液用量为1.0 mL)下,所建立的方法检测对苯二酚灵敏度良好：检测限为0.35 mg·L^-1,线性范围为0.5～4.5 mg·L^-1。该方法可用于美白霜中对苯二酚的快速测定,检测结果与文献报道的方法一致。     

间磺酸基偶氮安替比林光度法测定Cr(Ⅲ)

研究了Cr(Ⅲ)与间磺酸基偶氮安替比林(m-SAA)的显色反应.在pH=4.0的HAc-NaAc缓冲介质中,Triton X-100存在并加热的条件下,Cr(Ⅲ)与m-SAA形成稳定的1:1配合物,λmax=624nm,表观摩尔吸光系数为4.48×104L/(mol@cm),Cr(Ⅲ)的浓度在0～25.0μg/25 mL范围内符合比耳定律,检出限为5.9×10-3μg/25 mL.该方法应用于模拟合成水样和环境水样中铬的测定,回收率分别为105%和97%,相对标准偏差分别为3.2%和3.9%.     

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%.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

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.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

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.     

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.