对甲苯胺衍生高效液相色谱法测定夏桑菊中熊果酸的含量

建立了柱前衍生高效液相色谱紫外可见检测夏桑菊中熊果酸的分析方法。在CSz介质中用对甲苯胺衍生熊果酸,于C18柱上,以pH=6．2的甲醇-水(80：20,V／V)为流动相,290nm检测衍生物,熊果酸在0．3～30．0mg／L范围内与色谱峰高呈良好线性关系,r=0．9986,检出限为2．46μg／L。平均回收率为101．2％(n=5),相时标准偏差为2．5％。方法易行,可用于该制剂的质量控制。     

柱前衍生化高效液相色谱荧光检测法测定桑叶中的1-脱氧野尻霉素

建立了芴甲氧酰氯(FMOC—Cl)柱前荧光衍生一高效液相色谱法测定桑叶中1-脱氧野尻霉素(DNJ)的方法。桑叶经0．05mol／L,盐酸提取,在pH8．5的硼酸盐缓冲溶液条件下,DNJ反应生成荧光产物,然后用高效液相色谱-荧光检测器测定。流动相为乙腈-0．1％醋酸(55：45,V/V)。线性范围为0．567～34mg／L(相关系数r=0．9999);检出限为0．03mg／L。实验测得桑叶中DNJ含量为0．24％;平均回收率为97．1％,RSD为1．35％(n=6)。     

高效液相色谱-蒸发光散射检测法测定烟草中的水溶性糖

采用Waters高效糖分析柱,梯度洗脱分离,建立了高效液相色谱-蒸发光散射检测法（HPLC—ELSD）同时测定烟草中水溶性糖的新方法。乙腈-水为流动相,流速1．0mL／min,柱温30℃,蒸发光散射检测器漂移管温度80℃,氮气作载气,流速2．00L／min。水溶性糖的线性范围：鼠李糖、果糖、葡萄糖、蔗糖0．5—30μg,检出限低于12．5ng;木糖、阿拉伯糖、甘露糖、麦芽糖0．5—20μg,检出限低于25．0ng。8种水溶性糖的加标回收率范围为86．0％～102．4％;相对标准偏差（n=5）皆小于4．1％。     

利用差异衍生同步分析醛糖和酮糖

建立了一种可同时对醛、酮糖进行精确定性和定量分析的方法。以肌醇作为内标，用80％乙醇超声提取，利用醋酸酐和HMDS＋TMCS（1：3）进行差异衍生，在EI源下用SIM模式进行GC／MS分析。结果表明：11种标准单糖在1—4mg／L范围内线性良好；仪器检出限：醛糖在8．15—22．4μg／L之间；酮糖为2．32μg／L和3．47μg/L；高、中、低3个量的平均回收率在73．0％-95．7％，相对标准偏差在3．1％-10．0％。对枸杞游离单糖进行测定，各单糖含量分别在0．26—368．6mg／g。该方法弥补了以前单糖分析中的缺陷，对既含有醛糖又含有酮糖的样品可同时进行精确的定性定量分析。     

高效液相法测定注射用赖氨匹林中的阿司匹林及游离水杨酸

 建立了高效液相法 (HPLC)同时测定注射用赖氨匹林中阿司匹林和游离水杨酸含量的方法。采用的柱为HypersilBDSC18柱 ,流动相为甲醇 水 冰醋酸 (体积比为 35∶6 5∶3) ,检测波长为 2 80nm。阿司匹林和水杨酸的质量浓度分别为 0 0 2 8g/L～ 0 14 1g/L和 0 77mg/L～ 3 85mg/L时线性关系良好 ,其线性相关系数分别为0 9999和 0 9998;加样回收率分别为 99 2 7% (RSD =0 8% )及 99 6 1% (RSD =1 3% )。     

柱前衍生高效液相色谱法测定减肥药中的芬氟拉明

建立了柱前衍生反相高效液相色谱—紫外检测方法用于测定减肥药中的芬氟拉明。样品用三氯甲烷萃取,异丙醇转溶,再在四氢呋喃中和60℃下,用苯异氰酸酯衍生35min,然后用甲醇／水(72／28,V／V)为流动相和Kromasil C18分离柱,在240nm检测衍生物。方法的线性范围在2．52—126mg／L(r=0．9994),检出限和定量限分别为0．36ng(S／N=3)和1．2ng(S／N=10),平均回收率为98．4％,相对标准偏差(RSD)小于3．00％。     

顶空气相色谱法测定头孢氨苄中有机残留溶剂甲醇

采用顶空气相色谱法测定了头孢氨苄中有机残留溶剂甲醇的含量；以0．5mol/L氢氧化钠溶液为溶剂制备供试品溶液，以ChrompackCP-Si 8CB弹性石英毛细管柱为分离柱，研究了盐析效应、顶空加热温度和顶空热平衡时间对甲醇测定的影响；当添加水平为96．0μg时，回收率为98％～104％，测定相对标准偏差RSD为1．2％(n=6)，检出限为0．5mg／L(信噪比为3：1)，甲醇质量浓度为9．6～153．6mg／L时，线性相关系数为0．9999。     

高效毛细管电泳电导法快速检测复方维生素B片中的VBl、VBl2、VB6和VC

采用高效毛细管电泳电导法同时分离、测定了复方维生素B片中的主要成分VB1，VB12，VB6和VC的含量。研究了运行缓冲溶液的酸度和浓度、电泳电压、进样时间等因素对电泳的影响。在优化的实验条件下：40mmol/L Tris-4mmol/L H3BO3(pH8．0)的缓冲溶液中加入0．30mmol/L CTAB(溴化十六烷基三甲基铵)，分离电压为15kV，上述4组分在5min内得到良好的分离。维生素B1，B12，B6和VC的线性范围分别为5．5～1．0mg/mL；15～1．5mg／mL;1．0～0．40mg／mL和6．6～0．80mg／mL；检测限分别为0．80μg/mL，4．0μg/mL，0．50μg/mL，2．9μg/mL；5次测定峰高的相对标准偏差分别为2．2％，1．6％，3．9％，2．8％。5次测定的平均回收率分别为99％，94％，l00％，97％。     

液相色谱/蒸发光散射测定转基因烟草提取液中的海藻糖

 采用乙二胺动态修饰硅胶柱分离、蒸发光散射检测器测定了转基因烟草提取液中的糖。 4种糖的峰面积标准曲线在 10 0mg/L～ 15 0 0mg/L范围内均具有良好的线性关系。所建立的方法对果糖、葡萄糖、蔗糖、海藻糖的检测下限分别为 10mg/L ,2 0mg/L ,10mg/L和 10mg/L。     

高效液相色谱法测定烟草料液中的糖、甘油和丙二醇

研究了用高效液相色谱法测定烟草料液样品中糖、甘油和丙二醇的方法。烟草料液用Sep-Park-C18固相萃取小柱预分离，以Waters Surar-Pakl钙型阳离子交换柱为固定相，0．05g/L EDTA钙钠水溶液为流动相，示差折光仪为检测器，一次进样测定烟草料液样品中的糖、甘油和丙二醇。线性范围为0．005－5g/L,检测限在1．5－2．5mg/L之间，相对标准偏差为0．89％－1．3％，标准回收率在96．0％－103％之间。方法用于几种烟草料液样品测定，结果令人满意。     

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.     

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.     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.