流动注射化学发光法测定舒必利

实验发现,在亚硫酸钠存在下,高锰酸钾与舒必利能够发生反应,并产生较强的化学发光。据此采用流动注射技术,建立了利用高锰酸钾-亚硫酸钠-舒必利体系测定舒必利的化学发光分析法。方法线性范围为1.0×10-7~1.0×10-5g/mL;检出限为3.0×10-8g/mL;对1.0×10-6g/mL舒必利测定的相对标准偏差为1.5%(n=11);本法已用于片剂中舒必利含量的测定,结果与药典方法测定值一致。     

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...     

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.     

毛细管电泳-化学发光法测定人血清中的异烟肼

基于碱性介质中异烟肼对laminol-K3Fe(CN)6化学发光体系的增敏作用,设计了一个经毛细管电泳(CE)分离,在线化学发光检测异烟肼的新方法.研究并优化了毛细管电泳分离及化学发光检测的条件.在优化的实验条件下,该方法测定异烟肼的线性范围为4.0×10-7～1.0×10-5g/mL(R2=0.9984),检出限(3σ)为1×10-8g/mL,对6.0×10-6g/mL的异烟肼进行6次平行测定,其相对标准偏差为4.0%.方法已用于血清中异烟肼的测定.     

纳米金催化鲁米诺-硝酸银化学发光新体系测定头孢哌酮钠

在碱性条件下,以金纳米粒子为催化剂的鲁米诺-硝酸银发光体系,可产生很强的化学发光,头孢哌酮钠对该体系有抑制作用,基于此建立了一种测定头孢哌酮钠的新方法.在最佳实验条件下,用该法测定头孢哌酮钠的线性范围为5.0×10~(-7)~9.0×10~(-4) g/mL,检出限为1.0×10~(-7) g/mL,相对标准偏差为1.6%(ρ=3.0×10~(-6)g/mL,n=11).该法简便、快速、且线性范围宽,将其用于药物制剂中头孢哌酮钠含量的测定,测得平均回收率为101.2%,结果令人满意.     

纳米银参与的多潘立酮化学发光分析法研究

在碱性介质中,基于多潘立酮对纳米银(AgNPs)增敏Luminol-KMnO4化学发光体系发光信号的抑制作用,结合流动注射技术,提出了测定多潘立酮的化学发光分析新方法。在选定的流路和实验条件下,该方法测定多潘立酮的线性范围为1.0×10-8~5.0×10-6 g/mL,检出限为1.05×10-9 g/mL。对1.0×10-6 g/mL的多潘立酮溶液平行测定11次,其相对标准偏差(RSD)为1.7%。该法灵敏、准确、快速,用于样品中多潘立酮的测定,结果满意。     

偶合反应化学发光法测定过氧化苯甲酰

基于过氧化苯甲酰可以氧化K4Fe(CN)6生成K3Fe(CN)6,生成的K3Fe(CN)6在碱性溶液氧化鲁米诺可产生强的化学发光的特性,建立了测定过氧化苯甲酰的偶合反应化学发光新方法.该方法测定过氧化苯甲酰的线性范围为1.0×10-8～4.0×10-6 g/mL, 检出限为5×10-9 g/mL,相对标准偏差为3.0% (1.0×10-7 g/mL过氧化苯甲酰溶液,n=11).该方法已用于市售面粉中过氧化苯甲酰的测定.     

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。     

KMnO4-甲醛-茚三酮化学发光体系的研究

在甲醛存在下,KMnO4与茚三酮能够发生化学发光反应,产生很强的化学发光.据此采用流动注射技术,建立了一种利用KMnO4-甲醛-茚三酮化学发光体系测定茚三酮的方法.方法的检出限为3×10-8 g/mL;相对标准偏差为1.1%(4.0×10-6g/mL茚三酮,n=11);线性范围为1.0×10-7～2.0×10-4 g/mL.本法已用于样品中茚三酮的测定.     

胶束敏化化学发光法测定赤藓红

N-氯代丁二酰亚胺在碱性条件下可氧化赤藓红产生弱的化学发光.十六烷基三甲基溴化铵胶束的存在对这一反应的化学发光信号具有显著的增强作用.基于此,结合流动注射技术,优化了化学发光反应条件,建立了测定赤藓红的化学发光新方法.赤藓红质量浓度在1.0×10-7～1.0×10-5g/mL范围内与化学发光强度具有线性关系.该方法测定赤藓红的检出限为3×10-8g/mL,相对标准偏差为3.7%(1.0×10-6g/mL赤藓红溶液,n=11).该方法已用于糖果中赤藓红含量的测定.     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

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.     

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%).     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.     

Synthesis of N-substituted carbazolones from α-iodo enaminones via Pd(0)-catalyzed intramolecular coupling under microwave irradiation

A variety of N-aryl and N-alkyl carbazolones were conveniently achieved in good to high yields via Pd₂(dba)₃-mediated intramolecular coupling of N-substituted α-iodo enaminones under microwave irradiation. The Pd(0)-catalyzed cyclization was found to proceed favorably with the more electron-deficient phenyl ring during the reactions involving unsymmetrical N,N-diaryl α-iodo enaminones. This unique property enables the construction of carbazolone skeleton containing nitro substituted benzenoid ring.     

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.     

Synthesis of substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles by intramolecular nitrilimine cycloaddition

Both substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles have been synthesized by the 3+2 intramolecular dipolar cycloaddition of nitrilimines to alkynes. This cyclization has been extended to more versatile 3-bromo derivatives by the use of alkynylbromides as dipolarophiles.