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1.
丁基罗丹明B-碲钼杂多酸缔合显色反应的研究 总被引:2,自引:1,他引:1
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。 相似文献
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在过量溴化物存在下的稀磷酸介质中 ,I-被Cr(Ⅵ )氧化成I2 后与Br-结合形成[I2Br] -配阴离子 ,该配阴离子能进一步与罗丹明6G、罗丹明B、吖啶红等碱性吨染料阳离子形成离子缔合配合物。在聚乙烯醇存在下 ,缔合物体系稳定且溶液颜色有明显的变化 ,可用于I-离子的光度测定。方法具有高灵敏度 ,不同体系的摩尔吸光系数在4 .96×104 ~1 .1×105 L·mol-1·cm-1 之间 ,以罗丹明6G和罗丹明B体系灵敏度较高。碘离子质量浓度分别在0~0.8mg/L(罗丹明B和罗丹明6G体系)、0~1.0mg/L(吖啶红体系 )之间遵守比尔定律。方法具有良好的选择性 ,用于海带、黄豆和含碘药片的测定结果令人满意 相似文献
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甲基蓝与庆大霉素、妥布霉素的褪色反应及其应用 总被引:3,自引:0,他引:3
江虹 《理化检验(化学分册)》2004,40(3):166-168
在酸性条件下,硫酸庆大霉素(GEN)、硫酸妥布霉素(TOB)与甲基蓝(MB)反应,生成离子缔合物,使甲基蓝褪色,其最大褪色波长位于606nm(GEN)和610nm(TOB),表观摩尔吸光系数(ε)为1.80×104(GEN)和2.93×104(TOB)L·mol-1·cm-1;庆大霉素、妥布霉素浓度在0~1 2×10-5mol·L-1范围内遵从比耳定律。该法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。 相似文献
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铑(Ⅲ)-钼酸盐-丁基罗丹明B缔合显色反应的研究 总被引:1,自引:0,他引:1
在聚乙烯醇(PVA)存在下,铑与钼酸盐和丁基罗丹明B(BRB)形成寓于缔合物,缔合物的最大吸收峰位于570nm,摩尔吸光系数ε值为3.22×10~5L·mol~(-1)·cm~(-1),服从比耳定律范围0~8μgRh/25ml,摩尔比Rh:BRB1:4:,缔合物至少稳定240h。测定铑的适宜条件为C_(HCIO_4)=1.5mol/L,C_(MoO_4~(8-)),3.3×10~(-8)mol/L,C_(BRA)=3.8×10~(-5)mol/L,PVA0.08%。考察了41种共存离子的影响,常见元素不干扰。本法已用于催化剂和回收液中铑的测定,结果满意。本文还探讨了反应机理。 相似文献
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本文研究了丁基罗丹明B-砷钼杂多酸-PVA-124体系,由于形成高取代氢原子的杂多酸而使反应灵敏度大增,ε值高达6.9×10~5 L·mol~(-1)·cm~(-1)。缔合物的组成比As(V):BRB=1:7。红外光谱研究证明,染料和杂多酸形成了离子对缔合物。本法可成功地用于水样和试剂中痕量砷的测定。测定下限分别为2.0ppb(水样)和2×10~(-6)%(试剂)。 相似文献
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水溶苯胺蓝褪色光度法测定庆大霉素及妥布霉素的研究 总被引:3,自引:0,他引:3
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。 相似文献
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铕-伊文思蓝分光光度法测定新霉素及妥布霉素 总被引:2,自引:0,他引:2
在酸性条件下,铕(Ⅲ) 伊文思蓝(EB)与硫酸新霉素(NEO)或硫酸妥布霉素(TOB)反应生成三元蓝色离子缔合物。最大吸收波长位于668nm(NEO)和670nm(TOB);线性范围分别为0~15.5μg·mL-1(NEO)和0~15.0μg·mL-1(TOB);摩尔吸收光系数(ε)为1.19×105(NEO)和9.05×104(TOB)L·mol-1·cm-1;最大负吸收波长位于608nm,线性范围分别为0~16.5μg·mL-1(NEO)和0~16.0μg·mL-1(TOB),摩尔吸收光系数(ε)为1.54×105(NEO)和1.08×105(TOB)L·mol-1·cm-1。当用双波长叠加时,ε值为2.73×105(NEO)和2.00×105(TOB)L·mol-1·cm-1。该法已用于市售药物及尿液中新霉素和妥布霉素含量的测定,分析结果满意。 相似文献
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盐酸氯丙嗪-卤代荧光素体系的光度法测定 总被引:1,自引:0,他引:1
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。 相似文献
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Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction
Laurent Gavara Thomas Boisse Jean-Pierre Hénichart Adam Daïch Philippe Gautret 《Tetrahedron》2010,66(38):7544-5571
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. 相似文献
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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. 相似文献
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N. A. Nedolya 《Chemistry of Heterocyclic Compounds》2008,44(10):1165-1219
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. 相似文献
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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. 相似文献
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Rebecca J. Burton Mandy L. CrowtherNeal J. Fazakerley Shaun M. FilleryBarry M. Hayter Jason G. KettleCaroline A. McMillan Paula PerkinsPeter Robins Peter M. SmithEmma J. Williams Gail L. Wrigley 《Tetrahedron letters》2013
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. 相似文献
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Uroš Grošelj Mojca Žorž Amalija Golobič Branko Stanovnik Jurij Svete 《Tetrahedron》2013,69(52):11092-11108
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. 相似文献
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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. 相似文献
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Mohammed KajjoutChristian Rolando 《Tetrahedron》2011,67(25):4731-4741
Quercetin, the polyphenolic compound, which has the highest daily intake, is well known for its protective effects against aging diseases and has received a lot of attention for this reason. Both quercetin 3-O-β-d-glucuronide and quercetin 3′-O-β-d-glucuronide are human metabolites, which, together with their regioisomers, are required for biological as well as physical chemistry studies. We present here a novel synthetic route based on the sequential and selective protections of the hydroxyl functions of quercetin allowing selective glycosylation, followed by TEMPO-mediated oxidation to the glucuronide. This methodology enabled us to synthesize the five O-β-d-glucosides and four O-β-d-glucuronides of quercetin, including the major human metabolite, quercetin 3-O-β-d-glucuronide. 相似文献
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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. 相似文献