电生次氯酸根流动注射化学发光法测定L-多巴

将恒电流电解产生ClO~-与流动注射化学发光分析法结合,基于L多巴对ClO~-Luminol体系化学发光的抑制作用,建立了测定L多巴流动注射化学发光新分析法.该法测定L多巴的检出限为8×10~(-10)g/mL,线性范围为2×10~(-9)～1×10~(-7)g/mL,相对标准偏差为3.0%.该法具有简单、快速、灵敏的特点,应用于药片中L多巴的测定,结果满意.     

后化学发光法测定盐酸地芬尼多

本文研究了盐酸地芬尼多在N-氯代丁二酰亚胺(NCS)-荧光素化学发光反应体系中的后化学发光反应,并在研究反应的动力学性质、化学发光光谱、荧光光谱及其相关问题的基础上,探讨了反应机理;优化了反应条件,建立了一种测定盐酸地芬尼多的流动注射后化学发光方法.所建立方法的线性范围为6.0×10-9～1.0×10-9g/mL(r=0.9993),检出限为2×10-9g/mL,对5.0×10-8g/mL盐酸地芬尼多测定的相对标准偏差为2.5%(n=11).此法已用于血浆中盐酸地芬尼多含量的测定.     

NCS-核黄素-盐酸曲普利啶化学发光反应及其分析应用研究

以荧光试剂核黄素为化学发光试剂,构建了N-氯代丁二酰亚胺(NCS)-核黄素-盐酸曲普利啶化学发光新体系。利用此体系建立了测定盐酸曲普利啶的化学发光分析新方法,方法的线性范围为1.0×10-8～9.0×10-7g/mL,检出限为8×10-9g/mL,对浓度为1.0×10-7g/mL盐酸曲普利啶溶液进行11次平行测定的相对...     

流动注射后化学发光法测定盐酸阿比朵尔

研究了盐酸阿比朵尔在鲁米诺-K3Fe(CN)6化学发光反应体系中的后化学发光反应. 据此建立了测定盐酸阿比朵尔的流动注射后化学发光分析法. 方法的线性范围为6.0×10-9～1.0×10-7 g/mL, 检出限(3σ)为2×10-9 g/mL. 对4.0×10-8 g/mL的盐酸阿比朵尔溶液连续11次平行测定, RSD=1.3%. 方法已用于盐酸阿比朵尔胶囊及尿样中盐酸阿比朵尔含量的测定. 在对这一后化学发光反应的动力学性质、化学发光光谱、紫外可见吸收光谱以及一些相关问题研究的基础上, 提出了可能的反应机理.     

流动注射抑制化学发光法测定盐酸多西环素和土霉素

在酸性条件下,Ce(Ⅳ)-罗丹明6G发光体系有较强的化学发光,盐酸多西环素及土霉素的存在能抑制其发光。且化学发光信号的减小值(ΔI)与盐酸多西环素及土霉素的浓度在一定的范围内有较好的线性关系。据此结合流动注射技术,建立了快速测定盐酸多西环素及土霉素的流动注射化学发光分析新方法。优化了影响化学发光的各种因素。结果表明在优化的条件下,盐酸多西环素及土霉素的线性范围分别是1.0×10-7~1.0×10-4g/mL,1.0×10-6~1.0×10-4g/mL,测定的检出限为5.0×10-8g/mL及2.7×10-7g/mL,对1.0×10-6g/mL的盐酸多西环素及1.0×10-5g/mL的盐酸土霉素分别进行了9次平行测定,其相对标准偏差分别为1.4%、1.6%。方法已用于盐酸多西环素及土霉素片剂的测定。     

K3Fe(CN)6-钙黄绿素体系后化学发光反应测定盐酸氯丙嗪

发现了盐酸氯丙嗪在K3Fe(CN)6-钙黄绿素化学发光反应体系中的后化学发光反应,优化了反应条件,建立了一种利用后化学发光反应测定盐酸氯丙嗪的流动注射化学发光分析法.方法的检出限为3×10-8/mL,相对标准偏差为2.0%(2.0×10-6 g/mL盐酸氯丙嗪,n=11),线性范围为1.0×10-7～1.0×10-5 g/mL.此法已用于盐酸氯丙嗪片剂中盐酸氯丙嗪含量的测定,结果与药典方法测定值一致.     

偶合发光法测定熟肉制品中亚硝酸盐的含量

用亚硝酸盐把亚铁氰化钾氧化为铁氰化钾后,与鲁米诺、尿酸组成化学发光体系,建立了一种间接测定痕量亚硝酸盐的方法。探讨了酸度、反应物浓度、干扰离子等因素的影响。该方法的检出限为5.0×10~(11)g/mL,线性范围为1.0×10~(-9)～1.0×10~(-5)g/mL。对熟肉制品样品进行11次平行测定,回收率为92.8％～107.6％,测定结果的相对标准偏差为2.2％～3.9％。     

铁氰化钾-钙黄绿素体系后化学发光反应测定盐酸硫利达嗪

报道了盐酸硫利达嗪在铁氰化钾-钙黄绿素化学发光反应体系中的后化学发光反应。优化了反应条件,并建立了一种利用后化学发光反应测定盐酸硫利达嗪的流动注射化学发光分析法。方法的检出限为2.0×10-7g/mL,对2.0×10-6g/mL盐酸硫利达嗪测定的相对标准偏差为2.0%(n=11),线性范围为5.0×10-7～5.0×10-5g/mL。该法已用于盐酸硫利达嗪片剂中盐酸硫利达嗪含量的测定,结果与药典方法测定值一致。     

多巴酚丁胺的流动注射化学发光法测定

在盐酸介质中 ,高锰酸钾可氧化多巴酚丁胺产生化学发光 ,甲醛对该反应有较强的增敏作用 ,据此 ,建立了流动注射化学发光法测定多巴酚丁胺的方法 ;方法的线性范围为0.1～100mg·L -1,检出限为0.07mg·L -1 ,相对标准偏差为1.2 %(n=11,ρ=1.0mg·L -1) ;该法用于药物中多巴酚丁胺含量的测定 ,结果令人满意。     

Ru(bpy)_3~(2+)体系电化学发光法测定盐酸左氧氟沙星

基于盐酸左氧氟沙星对联吡啶钌(Ru(bpy)2+3)的电化学发光信号有较强的增敏作用,建立了一种检测盐酸左氧氟沙星的电化学发光分析新方法。结果表明,在0.1mol/L NaHPO4-KH2PO4介质中,以恒电位电解,Ru(bpy)2+3的浓度为1.0×10-5g/mL时,盐酸左氧氟沙星对Ru(bpy)2+3电化学发光信号的增敏效果最好。在此条件下,测定盐酸左氧氟沙星的线性范围为6~400×10-9g/mL,检出限为5.0×10-9g/mL,对8.0×10-9 g/mL盐酸左氟沙星平行测次11次,相对标准偏差(RSD)为1.9%。该方法已应用于人体尿样中盐酸左氧氟沙星的测定,并且用此方法对盐酸左氧氟沙星的国产及进口片剂进行了体外溶出度的测定。     

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.     

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.     

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.     

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.     

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.     

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.