Efficient Preparation of Isothiocyanates From Dithiocarbamates Using Bromineless Brominating Reagent

For the first time, the crystal structure of a ditribromide reagent 1,1′-(ethane-1,2-diyl)dipyridinium bistribromide (EDPBT) has been determined. Utilizing this thiophilic bromineless brominating agent EDPBT, highly useful synthetic intermediates (alkyl and aryl isothiocyanates) have been achieved directly from dithiocarbamates. EDPBT can be easily prepared from readily available reagents. It has been used as a thiophilic reagent, and its thiophilicity dominates over its brominating ability for substrates amenable to bromination. This is a sustainable process for the preparation of isothiocyantes because the spent reagent can be recovered, regenerated, and reused.     

Common methods for the chiral determination of amphetamine and related compounds I. Gas, liquid and thin-layer chromatography

This article reviews the most common, useful methods for the chiral determination of amphetamine (AM) and AM-derived designer drugs in different of matrix, including blood, hair, urine, medicaments or standard solutions, taking into consideration articles published in the past 15 years. We consider chromatographic methods (e.g., gas, liquid, high-performance liquid, and thin layer). We describe several types of chiral derivatization reagent, mobile-phase additive and chiral stationary phase commonly used in the chromatographic methods. Tables summarize basic information about conditions (e.g., type of column and mobile phase), detection mode and reference data for each procedure.     

Sulfuric acid {[3-(3-silicapropyl)sulfanyl]propyl}ester a recyclable catalyst for the synthesis of 2-aryl- 1-arylmethyl- 1H- 1,3-benzimidazole derivatives

A highly selective synthesis of 2-aryl-1-arylmethyl-1H-1,3-benzimidazoles from the reaction of o-phenylenediamine and aromatic aldehydes in the presence of sulfuric acid {[3-(3-silicapropyl)sulfanyl]propyl}ester(SASPSPE) in water and at 80℃in good to excellent yields.     

反相流动注射化学发光法测定牛血红蛋白的研究及应用

系统地研究了在碱性介质和阳离子表面活性剂CTMAB存在下,NaClO氧化异硫氰酸荧光素一牛血红蛋白标记物的化学发光行为和化学发光反应的条件,提出了反相流动注射化学发光测定牛血红蛋白的新方法。该方法测定牛血红蛋白的线性范围为0．26～12．8μg／mL,检出限为0．128μg／mL。     

激光光源-在线荧光光谱检测中的光强度比较研究

基于激光光源和氙灯光源在线荧光光谱法测定罗丹明B、维生素B₂、荧光素和异硫氰酸荧光素含量比较研究激光光源产生的荧光强度和氙灯光源产生的荧光强度。罗丹明B、维生素B₂、荧光素和异硫氰酸荧光素浓度均为10 μg·mL-1,积分时间100 ms,测定3次得其平均值。在线荧光光谱法最大吸收波长分别为580,450,488和510 nm;最大发射波长依次为594,530,525和524 nm。紫外-可见分光光度法测得其最大吸收波长为557,441,481和490 nm;荧光分光光度法测得其最大发射波长为586,520,519和520 nm。通过测定药物,发现激光光源产生的荧光光强度较强于氙灯光源产生的荧光光强度,原因不仅跟光源有关,而且与药物分子的共轭体系大小、共轭大π键的共平面性及其刚性程度、分子母体上取代基的种类有关,分子所处的外界环境如温度、溶剂、溶液酸碱度、激发光的照射等因素也会影响荧光效率。激光光源和氙灯光源产生的荧光光强度大小顺序为罗丹明B>荧光素>异硫氰酸荧光素>维生素B₂。激光光源在线荧光光谱法在一定程度上填补了在线荧光光谱仪在食品、药品痕量检测方面应用的空白。     

Synthesis and Crystal Structure of N3-（Dimethyl- pyrimidine）-N4-（tri-O-acetyl-xylosyl） Thiourea

The crystal structure of the title compound （C18H24N4O7S, Mr = 440.47） was prepared by the condensation of 2,3,4-tri-O-acetyl-β-D-xylopyranosyl isothiocyanate with 4,6-dimethylpyrimidin-2-amine and structurally determined by single-crystal X-ray diffraction. The crystal belongs to the monochnic system, space group P2 1 with a = 7.5500（17）, b = 10.498（2）, c = 14.208（3） A, β = 99.929（4）°, V = 1109.2（4） A^3, Z = 2, Dc = 1.319 g/cm^3,μ = 0.191, F（000） = 464, Flack = 0.00（15）, R = 0.0684 and wR = 0.1103. In the crystal structure, the xylose ring adopts a ^4C1 chair conformation. Due to the hydrogen bonding interaction between N（4）-H（4A） and N（1）, the pyrimidine ring is well positioned.     

Synthesis of environmental benign biolubricant from wild castor seed by reactive extraction and optimization

Castor oil alkyl esters are a possible biolubricant since they contain 90% hydroxyl fatty acid, which improves the oil's lubricity. Due to the limitations of the conventional approach, castor oil propyl ester (COPE) from wild castor seed was synthesized by reactive extraction. The factors influencing yield of reaction was optimised by response surface methodology to obtain a high yield. The influence of amount of catalyst, propanol to oil proportion, temperature, and rotating speed on castor oil propyl ester yield was investigated using a central composite design.The optimised reaction condition is propanol to oil molar proportion of 275: 1 with 1.5 wt% of catalyst loading at 90 °C and rotating speed of 450 rpm with COPE yield of 78.6% in 3hrs. Physico-chemical properties of alkyl esters were determined. COPE can be employed as a bioadditive to ultra-low sulphur diesel fuels due to its high lubricity.