孔雀石绿光度法测定阿魏酸钠

在pH=4.5的B-R缓冲介质中,阿魏酸可与孔雀石绿反应生成具有正吸收峰和负吸收峰的离子缔合物,其最大正吸收波长位于612nm,最大负吸收波长位于650nm,阿魏酸的质量浓度在0.2~3.9mg/L(正、负吸收)范围内与吸光度A呈线性关系,表观摩尔吸光系数ε分别为3.95×104 L/(mol·cm)(正吸收)和1.20×104 L/(mol·cm)(负吸收)。该方法用于市售阿魏酸钠药物中阿魏酸钠的测定,结果满意。     

简便吸收光谱法测定饮料中共存色素诱惑红和柠檬黄

建立了同时测定饮料中共存色素诱惑红和柠檬黄的简便吸收光谱法。在pH 7.2～8.7 Tris-HCl介质中,诱惑红和柠檬黄与双绿SF反应生成离子缔合物。诱惑红-双绿SF在可见光区有正吸收峰(496 nm)和负吸收峰(570 nm),诱惑红的质量浓度在0.03～12.4 mg/L范围内服从朗伯-比尔定律,表观摩尔吸光系数为1.79×104L/(mol·cm)(496 nm)和2.43×104L/(mol·cm)(570 nm),检出限为29μg/L (496 nm)和27μg/L(570 nm),定量限分别为0.78 mg/kg和0.73 mg/kg。柠檬黄-双绿SF在422 nm和660 nm处分别产生1个较强的正吸收峰,柠檬黄的质量浓度在0.04～13.4 mg/L范围内服从朗伯-比尔定律,表观摩尔吸光系数为2.13×104L/(mol·cm)(422 nm)和1.59×104L/(mol·cm)(660 nm),检出限为32μg/L(422 nm)和35μg/L(660 nm),定量限分别为0.87 mg/kg和0.95 mg/kg。当用双波长法测定时,表观摩尔吸光系(κ)为4.22×104L/(mol·cm)(诱惑红体系)和3.72×104L/(mol·cm)(柠檬黄体系),诱惑红体系的检出限和定量限分别为0.014 mg/L和0.38 mg/kg,加标回收率和相对标准偏差分别为98.0%～102%和2.3%～2.8%;柠檬黄体系的检出限和定量限分别为0.017 mg/L和0.46 mg/kg,加标回收率和相对标准偏差分别为97.5%～103%和1.1%～2.2%。该法适于饮料中诱惑红和柠檬黄的测定。     

头孢米诺与维多利亚蓝B的显色反应及应用

研究了头孢米诺与维多利亚蓝B之间的显色反应,确定了最佳反应条件,建立了简便、快速、灵敏测定头孢米诺的分光光度法。在pH=7.05的Tris-HCl缓冲介质中,适量的头孢米诺与维多利亚蓝B反应,生成具有明显正、负吸收峰的配合物。产物的最大正吸收波长为630nm,最大负吸收波长为424nm,表观摩尔吸光系数(ε)分别为4.20×104 L/(mol·cm)(正吸收)和1.69×104 L/(mol·cm)(负吸收)。头孢米诺质量浓度在0~5.2mg/L范围内服从比耳定律。该方法用于测定头孢米诺钠药物及人体尿样中头孢米诺的含量,结果满意。     

多波长吸收光谱法快速测定药物中的奥扎格雷钠

建立了快速测定药物中奥扎格雷钠的多波长吸收光谱法。在弱碱性Tris-盐酸缓冲介质中,奥扎格雷钠与甲基绿反应生成具有3个不同吸收强度的正吸收峰的绿色离子缔合物,最大正吸收峰位于660 nm,次大正吸收峰位于562 nm,相对最小的正吸收峰位于420 nm,它们的表观摩尔吸光系数(κ)分别为6.74×10~4L/(mol·cm)(660 nm)、4.47×10~4L/(mol·cm)(562 nm)和3.16×10~4L/(mol·cm)(420 nm),当采用双波长叠加法或三波长叠加法测定时,它们的表观摩尔吸光系数(κ)可达1.12×10~5L/(mol·cm)(562 nm+660 nm)和1.44×10~5L/(mol·cm)(420 nm+562 nm+660 nm),奥扎格雷钠的质量浓度在0.05~4.5 mg/L范围内服从比尔定律。以660 nm为例,采用单波长法测定了市售奥扎格雷钠药物中奥扎格雷钠的含量,加标回收率为99.1%~101.7%,相对标准偏差(n=6)为0.8%~1.2%。     

溴甲酚绿探针分光光度法测定奶粉中维生素B_1

在弱酸性条件下,溴甲酚绿与维生素B_1反应生成具有正、负吸收峰的离子缔合物,最大正吸收波长位于445 nm,最大负吸收波长位于615 nm,表观摩尔吸光系数(ε)分别为3.91×10~4(正吸收)和9.00×10~4(负吸收)L/(mol·cm)~(-1),维生素B_1的质量浓度在0~6.00mg·L~(-1)范围内服从比尔定律。若用正负光吸收叠加测定,灵敏度可提高到1.29×10~5L/(mol·cm)~(-1)。方法用于市售奶粉中维生素B_1的测定,回收率为98.7%~102%,测定值的相对标准偏差为1.6%~2.3%。     

多波长褪色分光光度法测定药物中的酒石酸美托洛尔

建立了测定药物中酒石酸美托洛尔的多波长褪色分光光度法,探讨了适宜反应条件、褪色光谱特征及共存物质的影响。在pH 5.66的Tris-盐酸缓冲介质中,酒石酸美托洛尔与固绿FCF反应生成具有3个负吸收峰(可见区)的二元离子缔合物,最大负吸收峰位于660 nm,另两吸收峰分别位于560 nm和426 nm,表观摩尔吸光系数(κ)分别为3.43×10~4(660 nm),2.53×10~4(560 nm)和2.57×10~4L/(mol·cm)(426 nm)。当用双波长或三波长叠加负吸收光谱法测定时,表观摩尔吸光系数分别可达5.96×10~4L/(mol·cm)(660 nm+560 nm)和8.53×10~4L/(mol·cm)(660 nm+560 nm+426 nm)。酒石酸美托洛尔的质量浓度在0.02~6.8 mg/L范围内服从朗伯-比尔定律。该方法用于市售酒石酸美托洛尔药物中酒石酸美托洛尔的测定,加标回收率为98.2%~102.7%,相对标准偏差RSD(n=6)为2.0%~2.3%。     

乙基紫褪色分光光度法测定药物中的美司那

建立了测定药物中美司那的褪色分光光度法。在酸性BR缓冲溶液中,美司那与乙基紫以静电引力作用生成具有2个较强负吸收峰的新物质,使溶液褪色,美司那的质量浓度在630 nm和492 nm处与生成的新物质的吸光强度的绝对值(|A|)有线性关系并服从朗伯-比尔定律,他们的线性范围为0.2～2.3 mg·L~(-1),表观摩尔吸光系数(κ)分别为1.71×10~4 L/(mol·cm)(492 nm)和2.53×10~4 L/(mol·cm)(630 nm),检出限分别为0.18 mg·L~(-1)和0.14 mg·L~(-1)。用双波长叠加法测定时,其表观摩尔吸光系数(κ)达4.24×10~4 L/(mol·cm),约是单波长法的2倍,检出限为0.080 mg·L~(-1)。该法用于市售美司那药物中美司那含量的测定,结果满意。     

三波长吸收光谱法测定药物中地奥司明

在弱酸性溶液中,地奥司明与亮绿反应生成具有3个强度相近负吸收峰的绿色二元离子缔合物。他们的负吸收波长分别位于424 nm、560 nm和660 nm处,表观摩尔吸光系数分别为5.84×10~4 L/(mol·cm)、6.02×10~4 L/(mol·cm)和5.76×10~4 L/(mol·cm)。当以双波长法(424 nm+560 nm)和三波长法(424 nm+560 nm+660 nm)测定时,其表观摩尔吸光系数分别达1.19×10~5 L/(mol·cm)和1.77×10~5 L/(mol·cm),线性范围均为0.03～12.2 mg/L。将灵敏度最高的三波长法用于市售地奥司明药物中地奥司明的测定,加标回收率为98.1%～102%,相对标准偏差(RSD,n=5)为2.0%～2.4%。     

双波长叠加吸收光谱法测定药物中的酒石酸美托洛尔

建立了快速、准确测定药物中酒石酸美托洛尔的双波长叠加可见吸收光谱法。在pH 4.55的酸性Tris-盐酸介质及586~740 nm波长范围内,偶氮氯膦Ⅲ与酒石酸美托洛尔反应生成具有两个明显正吸收峰的离子缔合物,最大正吸收波长位于614 nm,次大正吸收波长位于664 nm,表观摩尔吸光系数(κ)分别为6.03×10~4L/(mol·cm)(614 nm)和5.37×10~4L/(mol·cm)(664 nm),酒石酸美托洛尔的质量浓度在0.2~8.6 mg/L范围内服从朗伯-比尔定律,检出限为0.13 mg/L(614 nm)和0.15 mg/L(664 nm)。当采用双波长叠加法测定时,其表观摩尔吸光系数(κ)可达1.14×10~5L/(mol·cm),检出限为0.072 mg/L。该文同时探讨了显色反应的适宜条件、共存物质的影响及吸收光谱特征。实验发现,该反应体系的单波长及双波长叠加吸收光谱法的表观摩尔吸光系数可达5.37×10~4~1.14×10~5L/(mol·cm),方法可用于市售药物中酒石酸美托洛尔含量的测定,加标回收率为98.0%~101%,相对标准偏差(n=6)为1.8%~2.3%。     

柠檬酸与维多利亚蓝B的吸收光谱及应用

建立了一种新的、快速测定柠檬酸的吸收光谱法。在pH=9.02的Tris-HCl缓冲溶液中,柠檬酸与维多利亚蓝B反应生成一个具有明显正吸收峰和一个明显负吸收峰的蓝色离子缔合物,最大正吸收波长位于632 nm,最大负吸收波长位于428 nm,表观摩尔吸光系数(ε)分别为2.03×10~4、1.00×10~4 L/(mol·cm),柠檬酸的质量浓度在0~2.9 mg/L范围内服从比尔定律。优化条件下,采用双波长叠加法测定时,表观摩尔吸光系数可提高到3.03×10~4 L/(mol·cm)。方法用于市售新鲜柠檬中柠檬酸的测定,回收率为98.34%~101.8%,相对标准偏差为1.7%~2.2%。     

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%.     

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.     

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.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

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.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

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.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

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.     

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.