溴甲酚紫、溴甲酚绿光度法测定阿昔洛韦

在pH 3.30的NH2CH2COOH-NaCl-HCl缓冲介质中,阿昔洛韦(Aciclovir,ACV)可与溴甲酚紫(BCP)、溴甲酚绿(BCG)反应,形成离子缔合物,溶液颜色发生明显变化,其最大褪色波长分别为428 nm(BCP-ACV)、450 nm(BCG-ACV),在此波长处,阿昔洛韦的浓度与溶液褪色程度呈良好线性关系,可用分光光度法测定。在BCP-ACV、BCG-ACV体系的最大褪色波长处,ACV的浓度分别在0~2.69×10-5mol/L、0~2.58×10-5mol/L范围内遵守比耳定律,表观摩尔吸光系数分别为2.53×104L.mol-1.cm-1、1.79×104L.mol-1.cm-1,检出限分别为5.10×10-7mol/L、7.13×10-7mol/L。方法用于药品、血浆及尿液中阿昔洛韦的测定,结果满意。     

依文思蓝光度法测定水样中阳离子表面活性剂

在弱酸性的NaH2PO4-Na2HPO4缓冲介质中,阳离子表面活性剂(CS)溴化十六烷基吡啶(CPB)、十六烷基三甲基溴化铵(CTAB)与依文思蓝(EB)染料反应,形成离子缔合物,溶液颜色发生明显改变,最大褪色波长位于610 nm。在最大褪色波长处,CS的浓度与褪色程度呈良好线性关系,从而建立了测定阳离子表面活性剂的光度法。在最大褪色波长处,CS的浓度在5.0×10-7~2.46×10-5mol/L(EB-CPB)、9.0×10-7~3.36×10-5mol/L(EB-CTAB)范围内遵守比耳定律,表观摩尔吸光系数为1.97×104L.mol-1.cm-1(EB-CPB)、1.25×104L.mol-1.cm-1(EB-CTAB),检出限为3.6×10-7mol/L(EB-CPB)、7.4×10-7mol/L(EB-CTAB)。本法用于水样中阳离子表面活性剂的测定,结果满意。     

曙红Y分光光度法测定阳离子表面活性剂及其机理研究

在弱酸性的HCl-NaAc缓冲介质中,阳离子表面活性剂(CS)与曙红Y(EY)染料反应,形成离子缔合物,溶液颜色发生明显改变,最大褪色波长分别在514 nm(EY-CPB体系)、516 nm(EY-CTAB体系),同时在548 nm(CPB体系)、544 nm(CTAB体系)处有吸收峰,在褪色波长处阳离子表面活性剂的浓度与褪色程度呈良好线性关系,从而建立测定阳离子表面活性剂的光度法。在最大褪色波长处,CPB体系、CTAB体系中CS的浓度在0~4.79×10-5mol/L、0~2.90×10-5mol/L范围内遵守比尔定律,表观摩尔吸光系数为2.94×104、2.86×104L.mol-1.cm-1,检出限为8.97×10-7mol/L、7.87×10-7mol/L。若用双波长叠加,表观摩尔吸光系数达5.58×104、5.20×104L.mol-1.cm-1,检出限为5.87×10-7、6.25×10-7mol/L。方法适用于水样中CS的测定。本文还用密度泛函理论对反应机理进行了探讨。     

酚红分光光度法测定替米沙坦的含量

在pH为7.9的B-R缓冲体系中,酚红与替米沙坦作用,形成离子缔合物,溶液颜色发生改变,其最大显色和褪色波长分别为558,426 nm,替米沙坦的浓度与溶液的增色或褪色呈线性关系,建立了分光光度法测定替米沙坦的含量。在最大显色和褪色波长处,替米沙坦的浓度分别在6.50×10~(-7)～1.35×10~(-5)mol·L~(-1)和7.50×10~(-7)～1.00×10~(-5)mol·L~(-1)范围内遵守比耳定律,摩尔吸光率分别为6.59×10~4,2.12×10~4L·mol~(-1)·cm~(-1),检出限(3δ)分别为1.72×10~(-7),8.53×10~(-7)mol·L~(-1)。用于血样、尿样和药品中替米沙坦的测定,相对标准偏差(n=11)在0.72%～2.56%之间。     

刚果红褪色光度法测定盐酸西布曲明及作用机理研究

在弱酸性NaH_2PO_4-Na_2HPO_4的缓冲介质中,盐酸西布曲明与刚果红染料反应,形成离子缔合物,溶液颜色发生明显改变,褪色波长在342nm、490nm,其中最大褪色波长在490nm,从而建立了测定盐酸西布曲明的光度法。在最大褪色波长处,盐酸西布曲明的浓度在0.35~3.2×10-5mol/L范围内遵守比尔定律;表观摩尔吸光系数ε490为1.67×104L·mol-1·cm-1;检出限为4.45×10-7mol/L。方法具有较高的灵敏度和良好的选择性,用于曲美胶囊中盐酸西布曲明的测定,结果满意。本实验还用密度泛函理论对反应机理进行了探讨,结果与实验结果相符合。     

用刚果红分光光度法测定阳离子表面活性剂

在弱酸性的HCl-NaAc缓冲介质中,某些阳离子表面活性剂(CS)与刚果红(CR)反应,形成离子缔合物时,刚果红发生褪色作用,最大褪色波长分别在510nm(CR-溴化十六烷基吡啶(CPB)体系)、514nm(CR-十六烷基三甲基溴化铵(CTAB)体系)。在最大褪色波长处,CS的浓度在0~4.16×10-5mol.L-1(CPB体系)、0~3.18×10-5mol.L-1(CTAB体系)范围内遵守比尔定律,表观摩尔吸光系数为1.62×104L/(mol.cm)(CPB体系)、1.72×104L/(mol.cm)(CTAB体系),检出限为9.78×10-7mol.L-1(CPB体系)、1.04×10-6mol.L-1(CTAB体系)。方法具有较高的灵敏度和良好的选择性,用于水样中CS的测定,结果满意。     

阻抑褪色光度法测定水样中阴离子表面活性剂

在弱酸性的HCl-NaOAC缓冲介质中,溴化十六烷基吡啶(CPB)和曙红Y(EY)染料的混合溶液发生褪色,在该褪色的溶液中分别加入十二烷基硫酸钠(SDS)及十二烷基苯磺酸钠(SDBS)等阴离子表面活性剂(AS),溶液颜色发生改变,最大吸收波长都在514 nm处,并分别在548、546 nm处产生明显褪色。在吸收或褪色波长处,阴离子表面活性剂的浓度与增色或褪色程度呈良好线性关系,从而建立测定阴离子表面活性剂的光度法。在最大吸收波长处,SDBS体系、SDS体系中AS的浓度在0~2.06×10-5mol/L、0~2.63×10-5mol/L范围内遵守比尔定律,表观摩尔吸光系数分别为1.30×104、1.01×104L.mol-1.cm-1,检出限分别为8.14×10-7、9.96×10-7mol/L。若用双波长叠加,表观摩尔吸光系数达2.07×104、1.78×104L.mol-1.cm-1,检出限为4.82×10-7、8.34×10-7mol/L。方法具有较高的灵敏度和良好的选择性,用于水样中AS的测定。     

乙基曙红-溴化十六烷基吡啶光度法测定水样中阴离子表面活性剂

在弱酸性的HAC-NaAC缓冲介质中,将溴化十六烷基吡啶(CPB)与乙基曙红(EE)染料溶液混合,加入阴离子表面活性剂(AS),溶液颜色加深,最大吸收波长都在516nm处,且阴离子表面活性剂的浓度与溶液的增色程度呈良好线性关系。在最大吸收波长处,3种阴离子表面活性剂——十二烷基苯磺酸钠(SDBS)、十二烷基磺酸钠(SLS)及十二烷基硫酸钠(SDS)的浓度分别在0~2.05×10-5mol/L、0~2.08×10-5mol/L、0~2.04×10-5mol/L范围内遵守比尔定律,表观摩尔吸光系数分别为2.38×104、2.82×104和2.98×104L/(mol.cm),检出限分别为8.42×10-7、4.56×10-7和7.95×10-7mol/L。方法具有较高的灵敏度和良好的选择性,用于不同水样中AS的测定,结果满意。     

流动注射化学发光法测定片剂中阿昔洛韦含量

在碱性介质中,低浓度的阿昔洛韦会增强鲁米诺-H2O2体系的化学发光,据此建立了测定阿昔洛韦的新方法.该法的化学发光增强值ΔICL与阿昔洛韦的浓度在9.00×10-8～3.00×10-6mol/L范围内呈良好的线性关系,相关系数r为0.9957,检出限为7.71×10 -8mol/L.对1.00×10-6 mol/L的阿...     

偶氮氯膦Ⅰ分光光度法测定替米沙坦的含量

在pH=8.80的B-R弱碱性缓冲介质中,替米沙坦与偶氮氯膦Ⅰ染料反应形成离子缔合物,溶液颜色发生明显改变,最大吸收波长在558nm处,替米沙坦的浓度与溶液的变色程度呈良好的线性关系,从而建立了测定替米沙坦含量的光度法。在最大吸收波长处,替米沙坦的浓度在0～8.1×10-6mol/L范围内遵守比耳定律,表观摩尔吸光系数ε558为1.84×104L·mol-1·cm-1,检出限为8.63×10-7mol/L,研究了适宜的反应条件及影响因素。方法具有较高的灵敏度和良好的选择性,可用于市售药品、尿液及血浆中替米沙坦的测定。     

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%.     

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.     

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.     

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.     

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.     

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.