Spectral Studies on Some Pyrimidine Derivatives in Different Solvents

The electronic absorption spectra of 2-aminopyrimidine (compound I), 2-amino-4-methylpyrimidine (compound II), 2-amino-4,6-dimethylpyrimidine (compound III), 2-amino-4,6-dimethoxypyrimidine (compound IV), 4-amino-2,6-dimethylpyrimidine (compound V), and 4,5-diamopyrimidine (compound VI) have been measured in water and in a series of different organic solvents. The solvent effects on the spectra are discussed and the solvent induced spectral shifts are analyzed in terms of different solute–solvent interaction mechanisms, using the multiple linear regression technique.     

长脂链巴比妥酸和四氨基嘧啶的分子组装体的研究

长脂链巴比妥酸和四氨基嘧啶的分子组装体的研究王志强，王力彦，张希，沈家骢（吉林大学分子光谱与分子结构开放实验室，长春，１３００２３）关键词分子识别，分子组装体，长脂链巴比妥酸，四氨基嘧啶靠氢键、静电、疏水等弱相互作用及其协同作用，在气／液、液／液及液...     

巴比妥酸-NO_2~--铁(Ⅱ)-CPB显色体系光度测定巴比妥酸的研究

本文对巴比妥酸－ＮＯ－２－铁（Ⅱ）－ＣＰＢ显色体系进行了研究,建立了一种测定巴比妥酸的分光光度法,该法巴比妥酸含量在１．０×１０－６～２．０×１０－５ｇ／ｍＬ范围内符合比尔定律。方法简便、快速且具有良好的选择性及重现性,用于巴比妥类药物合成样中巴比妥酸的测定,回收率在９０．２％～１０２．１％     

靛蓝-F-组合探针光度法检测非质子有机溶剂中的微量水

以靛蓝-F^-为组合探针,建立了非质子有机溶剂(DMSO、THF、DMF、二恶烷、乙腈)中微量水的比色检测新方法。结果表明,F^-加入靛蓝溶液后体系的颜色由蓝色变为黄绿色,进一步加入微量水之后,体系从黄绿色又变回蓝色,因而可作为一种变色探针实现对有机溶剂中微量水的裸眼识别检测。体系具有较高灵敏度,对DMSO、THF、DMF、二恶烷及乙腈中微量水的检测限分别为0.022%、0.043%、0.016%、0.34% 和0.015%。该方法实验操作简便、快速、灵敏、安全。实验结果表明,靛蓝与F^-的结合比为1:2。利用核磁滴定方法对机理进行了探讨。     

巴比妥酸苯胺取代衍生物二阶非线性光学性质和电子光谱的INDO/CI研究

利用量子化学密度泛函理论（DFT）B3LYP方法，在6-31G~*基组下对巴比妥酸 苯胺取代衍生物体系BA1～BA5进行几何结构优化，以优化后的构型为基础，应用 INDO/CI方法进行电子光谱计算，并结合实验数据进行了分析，同时应用完全态求 和（SOS）公式计算二阶非线性光学（NLO）系数β_μ,设计的系列体系中β_μ最 大值可达到65.47×10~(-30)esu。进一步探讨了体系的共轭性和烷基取代基链的长 度对二者的影响，结果表明，体系的共轭程度越高，烷基取代基的链长度赵长，体 系β_μ值越大，而λ_max红移。     

Elastic Organic Crystals Based on Barbituric Derivative: Multi-faceted Bending and Flexible Optical Waveguide

Elastic organic single crystals with light-emitting and multi-faceted bending properties are extremely rare. They have potential application in optical materials and have attracted the extensive attention of researchers. In this paper, we reported a structurally simple barbituric derivative DBDT , which was easily crystallized and gained long needle-like crystals (centimeter-scale) in DCM/CH₃OH (v/v=2/8). Upon applying or removing the mechanical force, both the (100) and (040) faces of the needle-like crystal showed reversible bending behaviour, showing the nature of multi-faceted bending. The average hardness (H) and elastic modulus (E) were 0.28±0.01 GPa and 4.56±0.03 GPa for the (040) plane, respectively. Through the analysis of the single crystal data, it could be seen that the van der waals (C−H⋅⋅⋅π and C−H⋅⋅⋅C), H-bond (C−H⋅⋅⋅O) and π⋅⋅⋅π interactions between molecules were responsible for the generation of the crystal elasticity. Interestingly, elastic crystals exhibited optical waveguide characteristics in straight or bent state. The optical loss coefficients measured at 627 nm were 0.7 dBmm⁻¹ (straight state) and 0.9 dBmm⁻¹ (bent state), while the optical loss coefficient (α) were 1.5 dBmm⁻¹ (straight state) and 1.8 dBmm⁻¹ (bent state) at 567 nm. Notably, the elastic organic molecular crystal based on barbituric derivative could be used as the candidate for flexible optical devices.     

氯苯甲酸在水-DMF混合溶剂中的电离热力学

结构上彼此相关的取代苯甲酸在非水溶剂中电离热力学性质研究一直受到广泛的重视［‘一句，但是这类酸在水一DMF混合溶剂中的电离热力学性质的研究少见报导．DMF（N，N一二甲基甲酸胺）由于其独特性质，在许多化学、化工领域中已得到广泛的应用．本文对苯甲酸和。、。一、p氯苯甲酸在水一DMF混合溶剂中的电离热力学性质进行研究，以此深入地了解溶剂和取代基对弱酸电离的影响．1实验1．11热仪器用LKB－2277BioActivityMonitor问的流动混合测量系统部分，测量精度为0．2％（300Pw量程）1．2试剂苯甲酸为分析纯试剂，含量＞99．5％质…     

Spectrophotometric Determination of Methyldopa in Pure and Pharmaceutical Preparations

Abstract

Methyldopa reacts with barbituric acid to give a red colour having maximum absorbance at 540 nm. The reaction is selective for methyldopa with 0.01 mg/ml as visual limit of quantitation and provides a basis for a new spectrophotometric determination. The colour reaction obeys Beer's Law from 0.1 mg to 2.5 mg/10 ml of methyldopa and the relative standard deviation is 1.1%. The quantitative assessment of tolerable amount of other drugs is also studied.     

有机溶剂中微量水的荷移光谱法测定

研究了氯冉酸与有机溶剂中水的反应，确定了反应条件，氯冉酸与水的络合物的最大吸收波长为530nm。在乙醇、甲醇，正丙醇，异丙醇、正丁醇，正庚醇，正己醇溶剂中，水的含量分别在0－5％（V／V）或0－8％（V／V）范围内呈线性关系，相关系数为0．998或0．999；该方法重现性好，灵敏度高，操作简单，用于测定乙醇中微量水的含量，与标准值相符；加入回收法测得甲醇中水的回收率分别为98％－103％，结果令人满意。     

分光光度法测定水溶液中的有机酸含量

利用水溶液中的有机酸在高氯酸羟胺(HAP)和N,N′-二环己基碳酰亚胺(DCC)存在的条件下生成的羟肟酸,以及羟肟酸在酸性高氯酸铁溶液中显色的性质,建立了一种分光光度测定水中有机酸含量的方法。对显色剂的酸度、浓度、加入体积、HAP和DCC的浓度、加入体积以及显色反应的温度、反应时间对吸光度的影响进行了考察。结果表明,该显色反应在反应条件:0.0687mol/LHAP1.0mL、0.6mol/LDCC0.5mL、震荡均匀后室温下放置反应15min、0.02mol/L酸性高氯酸铁溶液(高氯酸浓度0.3mol/L)显色条件下具有最大的吸光度;并对正丁酸、正戊酸、苯甲酸进行了线性关系考察。结果表明,该检测方法具有仪器简单、操作方便、线性范围较宽、准确度高等优点,可用于那些不易从水溶液中萃取的有机酸的测定,也可用于液相色谱洗脱液中有机酸的测定。     

有机介质对2,3—二氨基吩嗪的荧光增敏作用研究

研究了有机介质对漆酶催化氧化邻苯二胺的产物－２，３－二氨基吩嗪（ＤＡＰ）的光谱性质的影响，结果表明，极性有机介质对其吸收光谱影响较小，但对其荧光具有强烈的增敏作用，荧光量子效率可提高近３０倍，据此，建立了有机介质增敏荧光测定ＤＡＰ的新方法，进一步研究表明：有机介质对２，３－二氨基吩嗪的荧光增敏原因在于其增溶作用，供电子效应及对ＤＡＰ分子吸收性能的增强。     

巴比妥酸的质子迁移异构化反应及其芳香性的密度泛函研究

用密度泛函理论方法,在B3LYP/6-31G水平上研究了巴比妥酸的醇式和酮式结构的分子内质子迁移异构化反应,对反应势能面的研究发现,该化合物可能存在6种中间体和12种过渡态,对反应物、产物和过渡态进行了几何构型优化,在同一水平下计算了单点能量,并用频率振动模式和内稟坐标(IRC)确证了过渡态的存在,反应的活化能最小为107.50kJ·mol-1,最大为330.84kJ·mol-1。在GIAO-HF/6-31G//B3LYP/6-31G水平对反应物、产物,中间体和过渡态的非相关性化学位移(NICS)进行了计算,利用NICS值对反应过程中芳香性进行分析,发现如果分子中的C5与C6存在双键或者形成过渡态的四员环状结构,分子就有不同程度的芳香性,如果有C6上的羟基氢迁移到C5上,C5-C6以单键相结合,则分子就没有芳香性。     

Interaction Between Surface Active Solutes and Surfaces of Metal Oxides in Polar Organic Solvents

Ionic surfactants are efficient as charge-controlling agents in very polar and in completely non-polar solvents. On the other hand in polar organic solvents of dielectric constants of about 25, the effect of ionic surfactants on the ζ potential is often insignificant. Weak acids can be used to control the ζ potential of TiO₂ in solvents, in which ionic surfactants are not efficient. Phosphoric acid alone and combined with bases is useful as charge-controlling agent in aliphatic alcohols and in DMSO.     

Miceliization and Surface Adsorption of Tetraethylammonium Perfluorooctanesulfonate in Mixed Solvents

The surface tension and cenductivity of tetracthylarnmomum perfluorooctanesulfonate (TEPFOS) solu-tions in mixed solvents were determined The criticsl micelle concentrations (cmc) and surface adsorption of TEPFOS in various solvents (Dimetbylsulfoxlde and DMSO, formamide and FA, and DMSO-H2O and FA H2O mixtures) were calculated from the above experimental date. The results show that the surface activity of TEPFOS is much higher than that of typical hydrocarbon surfactant, sodium dodecylsulfate (SDS); the melecalar interaction (in terms of colubility araneter or surface tension) of solvent is the decisive factor in sffecting the cmc of TEPFOS , in the apretic solvent DMSO, the value of entropy change during micelliza-tion of TEPFOS may beecme subsantially negative; the surfaof adsorption amount of TEPFOS is the largest in H2O, smaller in FA , and the smallest in DMSO.     

Enzymatic Synthesis of Dipeptide Derivatives Containing Non-coded Amino Acids in Organic Solvents

ＩｎｔｒｏｄｕｃｔｉｏｎＥｎｚｙｍａｔｉｃｐｅｐｔｉｄｅｓｙｎｔｈｅｓｉｓｈａｓｄｒａｗｎｍｕｃｈａｔｔｅｎ ｔｉｏｎｂｅｃａｕｓｅｏｆｉｔｓａｄｖａｎｔａｇｅｏｆｅｎｚｙｍｅｓｔｅｒｅｏｓｐｅｃｉｆｉｃｉｔｙ ,ｍｉｌｄｒｅａｃｔｉｏｎｃｏｎｄｉｔｉｏｎｓ ,ｍｉｎｉｍｕｍｓｉｄｅ ｃｈａｉｎｐｒｏｔｅｃｔｉｏｎａｎｄａｖｏｉｄａｎｃｅｏｆｒａｃｅｍｉｚａｔｉｏｎ .Ｂｕｔｔｈｅｓｔｒｉｃｔｓｕｂｓｔｒａｔｅｓｐｅｃｉｆｉｃｉｔｙｏｆｔｈｅｅｎｚｙｍｅｓｌｉｍｉｔｓｔｈｅｉｒａｐｐｌｉｃａｔｉｏｎｓ .…     

Extraction of Bioactive Components from Chamaenerion angustifolium (L.) Scop. with Choline Chloride and Organic Acids Natural Deep Eutectic Solvents

Chamaenerion angustifolium (L.) Scop. (fireweed) is a perennial herbaceous plant of the Onagraceae family widely used in folk and scientific medicine. It is a promising source of bioactive components. One of the modern trends in extraction is the use of natural deep eutectic solvents (NADESs) combined with ultrasound-assisted extraction (UAE). However, works devoted to the extraction of biologically active substances from C. angustifolium using NADESs are scarce. The aim of this work is a comprehensive study of UAE of bioactive components from C. angustifolium using NADESs based on choline chloride and malonic, malic, tartaric, and citric acids. The antioxidative properties, total phenols, and flavonoids content were estimated for NADES-based extracts. The reference solvents were water and 90% v/v ethanol. Volatile extracted components were identified using GC-MS. The kinetics of the UAE were studied at 45 °C for 20–180 min with water added to 30 wt% NADES. The power of the ultrasound was 120 W, and the frequency was 40 kHz. It was found that NADES choline chloride + citric acid is more effective for the extraction of bioactive components. For this, NADES UAE conditions were optimized following a Box–Behnken design of the experiment and a response surface methodology. The temperature ranged from 30 to 60 °C, the time of extraction ranged from 20 to 60, and the addition of water ranged from 30 to 70 wt%. We established the optimal extraction conditions: temperature 58 °C, time of extraction 35 min, and 70 wt% water. The obtained results expand the knowledge about the use of NADES for the extraction of biologically active compounds from cheap and available plant raw materials.     

Thin Later Chbomatography of Amino Acids on Tin(IV) Arsenosilicate Cation Exchanger in Some Buffer Solutions

Abstract

Inorganic ion exchanger tin(IV) arsenosillcate (TAS) has been used in the thin layer chromatographic study of 24 amino acids in various buffer solutions as the mobile phases. On the basis of the differential movement, some important binary separations of amino acids have been achieved, particularly those of basic fro acidic or neutral amino acids.     

Activity and Enantioselectivity of the Hydroxynitrile Lyase MeHNL in Dry Organic Solvents

Water concentration affects both the enantioselectivity and activity of enzymes in dry organic media. Its influence has been investigated using the hydrocyanation of benzaldehyde catalyzed by hydroxynitrile lyase cross‐linked enzyme aggregate (MeHNL‐CLEA) as a model reaction. The enzyme displayed higher enantioselectivity at higher water concentration, thus suggesting a positive effect of enzyme flexibility on selectivity. The activity increased on reducing the solvent water content, but drastic dehydration of the enzyme resulted in a reversible loss of activity.     

Studies on Synthesis and Biological Activities of Novel Triazole Compounds Containing Pyrimidine or N,N-Dialkyldithiocarbamate Ring

IntroductionAs an important type of fungicides,triazolecompounds are highly efficient,low poisonous andinward absorbents[1— 4] .At present,the studies ontriazole derivatives have mainly been concentratedon the compounds with triazole group as the onlyactive group.The report of triazloe compoundsthat contain both a triazole group and other activegroups in a single molecule has rarely been found.Some pyrimidines have been used as high efficientand low poisonous fungicides[5] in control of pow-d…