紫尿酸–Fe(Ⅲ)分光光度法测定盐酸羟胺

在碱性介质及溴化十六烷基吡啶存在条件下,盐酸羟胺与Fe(Ⅲ)–紫尿酸体系发生显色反应形成离子缔合物,该离子缔合物在635 nm波长处有一个吸收峰,其表观摩尔吸光系数ε=2.05×104 L/(mol·cm),据此建立了测定盐酸羟胺的间接分光光度法。盐酸羟胺的质量浓度在0~2.4 mg/L范围内与吸光度与呈良好的线性,线性相关系数r=0.999 8,方法的检出限为0.01 mg/L。将该方法用于盐酸羟胺的测定,其测定结果与国标法测定结果相吻合,加标回收率为95.0%~104.0%,测定结果的相对标准偏差为0.51%~1.29%(n=5)。该方法灵敏度高,操作简便,可用于盐酸羟胺含量测定。     

邻二氮菲分光光度法测定盐酸氯丙嗪

在HAc-NaAc缓冲介质中,盐酸氯丙嗪(CPZ)能定量使Fe(Ⅲ)还原为Fe(Ⅱ),还原生成的Fe(Ⅱ)与邻二氮菲反应生成稳定的红色络合物,并且在一定范围内,CPZ的浓度和生成的红色络合物的吸光度呈良好的线性关系。据此,提出邻二氮菲-Fe(Ⅲ)体系测定盐酸氯丙嗪的新方法。在优化的实验条件下,盐酸氯丙嗪的质量浓度在0.040～15.00 mg/L范围内与吸光度呈现良好的线性关系,线性相关系数R=0.9995,摩尔吸光系数ε=2.8×104 L.mol-1.cm-1,检出限为0.020 mg/L。11次重复测定的相对标准偏差小于2.9%。该方法用于药物中盐酸氯丙嗪的测定,结果满意。     

Spectrophotometric determination of chlorpromazine hydrochioride by 1,10-phenanthroline

在HAc-NaAc缓冲介质中,盐酸氯丙嗪(CPZ)能定量使Fe(Ⅲ)还原为Fe(Ⅱ),还原生成的Fe(Ⅱ)与邻二氮菲反应生成稳定的红色络合物,并且在一定范围内,CPZ的浓度和生成的红色络合物的吸光度呈良好的线性关系.据此,提出邻二氮菲-Fe(Ⅲ)体系测定盐酸氯丙嗪的新方法.在优化的实验条件下,盐酸氯丙嗪的质量浓度在0.040～15.00mg/L范围内与吸光度呈现良好的线性关系,线性相关系数R=0.9995,摩尔吸光系数ε=2.8×104L·mol-1·cm-1,检出限为0.020mg/L.11次重复测定的相对标准偏差小于2.9％.该方法用于药物中盐酸氯丙嗪的测定,结果满意.     

Fe(Ⅲ)分光光度法测定盐酸氯丙嗪

建立了以Fe(Ⅲ)为氧化剂分光光度法测定盐酸氯丙嗪的方法。在盐酸介质中,Fe(Ⅲ)将盐酸氯丙嗪氧化形成一种红色化合物,该化合物的最大吸收波长位于525 nm,其摩尔吸光系数ε=1.05×104 L/(mol·cm)。盐酸氯丙嗪的质量浓度在0~20.0 mg/L范围内与体系的吸光度呈良好的线性关系,线性相关系数r=0.999 2,加标回收率为94.0%~100.4%,测定结果的相对标准偏差为0.55%~1.42%(n=6)。该法灵敏度较高、选择性及重现性良好,可用于药品和血清中盐酸氯丙嗪的测定。     

铁氰化钾-Fe(Ⅲ)分光光度法测定盐酸氯丙嗪

建立了以铁氰化钾-Fe(Ⅲ)体系测定盐酸氯丙嗪的新方法.研究表明,盐酸氯丙嗪可以使Fe(Ⅲ)还原为Fe(Ⅱ),还原生成的Fe(Ⅱ)可以与K3[Fe(CN)6]反应生成可溶性普鲁士蓝KFe[Fe(CN)6].盐酸氯丙嗪的质量浓度在0.21-32.00μg/mL范围内与吸光度呈现良好线性关系,线性回归方程A=0.01854+0.07652p(μg/mL),相关系数R=0.9992,摩尔吸光系数ε=2.5×10(4)·L·mol-1·cm-1,检出限0.12μg/mL.方法用于测定药物和血清中盐酸氯丙嗪含量,回收率为98.1%～101.3%.     

紫尿酸树脂相光度法测定痕量铁

树脂相光度法属于固相光度法,由于该法集分离富集于一体,因而具有较好的选择性及较高的灵敏度,已应用于多种金属离子的定量分析。以邻二氮菲为显色剂的树脂相光度法测定铁文献[3]也有报道。本文根据碱性条件下Fe(Ⅱ)与紫尿酸(VA)可形成稳定的蓝色配阴离子的原理,以苯乙烯型强碱性阴离子交换树脂吸附铁的配阴离子,在620nm测定树脂相的吸光度,建立了文献未见报道的痕量铁的紫尿酸树脂相光度测定法,方法线性范围为Fe(Ⅱ)0～25.0μg/29ml,其灵敏度约为水相光度法的10倍,方法用于自来水中铁的测定,结果令人满意。     

氮气-苯浮选光度法测定痕量锰

提出了根据 Mn( )氧化 I-生成 I2 ,I2 与 I-反应生成 I-3 配阴离子 ,I-3 配阴离子与孔雀绿阳离子发生离子缔合反应 ,用苯和 N2 将此缔合物浮选 ,以光度法测定此缔合物间接测量锰新方法。表观摩尔吸光系数为(ε=5.0 4× 1 0 5 L· mol-1· cm-1) ,测定 5.0μg/2 0 0 m L的锰 ( n=6 ) RSD为 1 .8%。已用于水中锰的测定。     

紫尿酸双波长叠加光度法测定水中微量铁

在碱性介质中,铁（Ⅱ）与紫尿酸发生显色反应形成一种蓝色配阴离子,该配阴离子具有两个吸收峰,分别位于630nm和350nm,吸光度A630,A350之和△A与铁（Ⅱ）的含量在0-2μg／mL范围内线性关系良好,据此建立了测定微量铁的紫尿酸双波长叠加光度法,该法用于水中微量铁的测定,测定结果与火焰原子吸收法（FAAS）相吻合,加标回收率为98％-102％,测定结果的相对标准偏差为1．2％-2．9％（n=5）。     

铬天青S–盐酸氯丙嗪–溴化十六烷基三甲铵光度法测定水样中的铁

采用铁(Ⅲ)–铬天青S–盐酸氯丙嗪–溴化十六烷基三甲铵(CTMAB)四元配合物光度法测定水样中铁的含量。在pH 5.50的HAc–NaAc缓冲介质中,在铁(Ⅲ)–铬天青S–盐酸氯丙嗪显色反应中,加入CTMAB,四元配合物的表观摩尔吸光系数为9.85×10~4 L/(mol·cm),是三元配合物灵敏度的两倍。结果表明,配合物在657nm波长处有最大吸收,Fe(Ⅲ)的质量浓度在0~20μg/(25 mL)范围内与吸光度呈良好的线性关系,线性相关系数为0.999 6,方法的检出限为1.84×10~(–3) mg/L。样品加标回收率为97.3%~98.8%,测定结果的相对标准偏差为1.9%~3.2%(n=5)。该方法灵敏度高,精密度与准确度好,便于在实验室推广应用。     

紫尿酸光度法测定微量铁

紫尿酸(VA)是一种金属指示剂,已用于Cu~(2 )的滴定分析.在碱性条件下,VA与Fe(Ⅱ)发生灵敏的配合反应形成一种稳定的蓝色配阴离子,该配阴离子在620nm和350nm处各有一个正吸收峰,其ε_(620)=1.93×10~4,ε_(350)=2.64×10~4,且配阴离子在620nm和350nm的吸光度及其两者之和(A_(620 350)均与Fe(Ⅱ)在0～50.0μg/29.0ml呈良好的线性关系,据此本文建立了以VA为显色剂,采用三种测量方式即分别在620nm(方式Ⅰ)、350nm(方式Ⅱ)或在两波长下(方式Ⅲ)测定微量铁的光度法.方法用于自来水中铁的测定.获得了令人满意的结果.1 试验部分1.1 仪器与试剂7520型紫外/可见分光光度计721分光光度计     

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.