阿奇霉素与百里香酚蓝的荷移反应及其在药物测定中的应用

基于阿奇霉素与百里香酚蓝在无水乙醇介质中可以发生荷移反应,建立了测定阿奇霉素的新方法.在无水乙醇溶剂中,阿奇霉素与百里香酚蓝发生荷移反应,其荷移络合物在550 nm处有最大吸收峰.由吸光度测定阿奇霉素的含量.表观摩尔吸光系数ε=8.5×103 L·mol-1·cm-1,络合物组成比为1:2.稳定常数为1.0×1010,阿奇霉素质量浓度在2.52～21.0μg/mL内与吸光度呈良好的线性关系,线性回归方程为A=-0.02242+0..167ρ(μg/mL),线性相关系数R=0.9994,检出限(3ρ/k)为2.52μg/mL,相对标准偏差为1.4%.     

阿奇霉素与茜素的电荷转移反应及其测定

建立了一种快速测定阿奇霉素的荷移分光光度法。阿奇霉素与茜素在乙醇介质中发生电荷转移反应 ,电荷转移络合物在 5 4 6nm处有最大吸收 ,表观摩尔吸光系数为 5 .79× 10 3 L·mol-1·cm-1;该络合物的组成是 1∶1;稳定常数为 4 .8× 10 3 ;药物浓度在 5～ 12 0mg/L范围内服从比耳定律。利用本法测定了阿奇霉素制剂中有效成分的含量 ,并与文献法进行比较 ,二者结果基本吻合。     

高效液相色谱电化学检测法测定阿奇霉素及相关组分

提出了用高效液相色谱电化学检测法同时测定阿奇霉素颗粒中阿奇霉素(AZMC)及相关组分(即脱糖氧胺阿奇霉素、阿奇霉素A及N-去甲基阿奇霉素)含量的方法.采用Thermo C18柱(150 mm×4.6 mm,5μm)作固定相分离上述4组分.以20 mmol·L-1磷酸二氢钾(用1 mol·L-1氢氧化钾溶液调pH为7.37)-甲醇(47+53)为流动相,流量为1.0 mL·min-1,电化学检测电位为1.05 V,柱温为35℃.阿奇霉素及相关组分的峰面积值与相应浓度之间的线性范围依次为37.06～593.00,2.63～84.00,9.20～294.50,6.69～107.00 mg·L-1,检出限(3S/N)分别为9.28,1.32,4.60,3.35 mg·L-1.用标准加入法作回收试验,测得平均回收率分别为99.9%,100.6%,99.9%,99.8%.     

紫色素荷移分光光度法测定阿奇霉素

提出了紫色素荷移分光光度法测定阿奇霉素。在乙醇介质中,阿奇霉素与紫色素生成的荷移络合物在546nm处产生一个强的吸收峰。在最佳反应条件下,吸光度与阿奇霉素的质量浓度在8.0~120mg·L-1范围内呈线性关系,检出限(3s/k)为2.6mg·L-1。该法用于分析市售阿奇霉素片剂,测定值与标示值相符。加标回收率在98.8%~101%之间,测定值的相对标准偏差(n=5)在1.7%~2.4%之间。     

克拉霉素与紫色素的荷移反应及其测定

建立了一种测定克拉霉素的荷移分光光度法。克拉霉素与紫色素在乙醇溶液中发生电荷转移反应,荷移络合物在548nm处有最大吸收,表观摩尔吸光系数是4.49×103L·mol-1·cm-1,该络合物的组成是1∶1;稳定常数是3.48×104;药物浓度在10~150mg/L范围内服从比耳定律。当克拉霉素浓度为100mg/L时,6次测定结果的相对标准偏差为1.2%。利用本法测定了克拉霉素制剂中有效成分的含量,并与文献法进行比较,二者结果基本吻合,回收率在97.0%以上。     

对苯醌与克拉霉素的荷移反应及其应用

研究了对苯醌与克拉霉素之间的荷移反应。对苯醌与克拉霉素于39℃在甲醇–水(1∶2)中反应60 min,可生成稳定的荷移络合物,络合物在360 nm处的吸光度与克拉霉素的质量浓度在37.40~186.99 mg/L范围内呈良好的线性关系,线性方程为A=0.002 54ρ+0.597 79,相关系数r=0.998 6。该方法应用于样品中克拉霉素含量的测定,回收率为97%~104%,测定值的相对标准偏差为3.56%(n=5)。该反应可用于测定克拉霉素的含量。     

克拉霉素与苯基荧光酮的荷移反应及其测定

本文建立了一种测定克拉霉素的荷移分光光度法,克拉霉素与苯基荧光酮(PF)在乙醇溶液中发生荷移反应,荷移络合物在波长519nm处有最大吸收,其表观摩尔吸光系数为1.70×104 L·mol-1·cm-1,荷移络合物的组成比为1∶1,稳定常数为2.86×104,药物浓度在5.0×10-6~7.0×10-5 mol/L范围内服从比耳定律,当克拉霉素浓度为4.0×10-5 mol/L时,8次测定结果的相对标准偏差(RSD)为0.46%,检出限为6.0×10-7 mol/L。利用该法测定了克拉霉素胶囊中有效成分的含量,回收率大于98%以上。     

少量水存在下桂利嗪和茜素在甲醇中的荷移反应

研究了在少量水存在下桂利嗪和茜素在甲醇介质中的电荷转移反应,确定了最佳反应条件。研究表明,反应生成1∶1型荷移络合物,该络合物的λmax=527nm,表观摩尔吸光系数ε=2.94×103L·mol-1·cm-1,桂利嗪浓度在25～200mg/L范围内符合比尔定律,相对标准偏差为1.55%(n=6),平均回收率在98%以上。     

Ru (bpy)2+3体系电化学发光法测定阿奇霉素的研究

实验发现,阿奇霉素对联吡啶钌的电致化学发光(ECL)具有显著的增强作用.据此,建立了以金电极为工作电极的测定阿奇霉素ECL分析新方法.采用了循环伏安(CV)和ECL法,研究了阿奇霉素对联吡啶钌体系的电化学行为和ECL行为的增强作用.结果表明,在最佳条件下,阿奇霉素浓度在2.0×10-4～4.0×10+7moL/L范围内...     

N-亚水杨基氨基酸的某些过渡金属络合物的合成及薄层色谱与紫外光谱的研究

本文合成了甘氨酸、苯氨酸水杨醛席夫(Schiff)碱及其Mn(Ⅱ)、Co(Ⅱ)、Ni(Ⅱ)Cu(Ⅱ)和Zn(Ⅱ)的络合物.元素分析和摩尔电导测定的结果证明,氨基水杨醛Schiff碱的3d金属络合物配位比为1:1,络合物为非电解质.在硅胶G板上,以甲醇-乙醇-丙酮-水[2.22:4.44:3.33:0.5(体积比)]为流动相研究了络合物的薄层色谱行为,各组分络合物得到了满意的分离,且R_1值以下列顺序递增:R_1(Mn)R_1(Zn).讨论了该系列络合物薄层色谱比移值(R_1)与紫外光谱R带λmax变化关系的一致性.     

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.