中成药中马兜铃酸A的HPLC/MS分析方法

建立了中成药中马兜铃酸A的高效液相色谱/质谱检测方法.测定结果表明,马兜铃酸A的质谱有较强的分子离子峰,最低检测限为5 ng(信噪比等于10),可以满足对中成药中马兜铃酸A测定之要求.     

超高效液相色谱-电喷雾三重四极杆质谱法测定中药中马兜铃酸A和B的含量

利用超高效液相色谱-电喷雾三重四极杆质谱仪建立了中药中马兜铃酸A和B的定性定量分析方法。选取柴胡、生甘草、桔梗、龙胆泻肝丸、消胖丸、减肥茶等14种代表性样品,用甲醇-水(70:30, v/v)溶液加热回流提取,经Oasis MAX固相萃取柱富集净化后,在Eclipse RP HD C18反相柱(150 mm×2.1 mm, 1.8 μm)上进行分离;流动相为5 mmol/L乙酸铵水溶液(pH 7.5)-乙腈(75:25, v/v)。采用电喷雾离子源正离子模式(ESI+)和多反应监测模式(MRM)进行质谱分析。马兜铃酸A和B的线性范围分别为0.5～200 μg/L和1～200 μg/L,相关系数(r2)均大于0.995;检出限(LODs)分别为5 μg/kg和7.5 μg/kg;定量限(LOQs)分别为12.5 μg/kg和25 μg/kg。在100 μg/kg和500 μg/kg添加水平下,马兜铃酸A和B的回收率(n=6)范围分别为60.3%～96.4%和61.3%～94.7%,相对标准偏差均不大于10.2%。该方法灵敏度高,重复性好,操作简便,适用于中药材、饮片及中成药中马兜铃酸A和B的痕量检测。     

马兜铃酸的电化学性质及其在关木通中的含量测定

在pH 5.0的Britton-Robinson缓冲溶液中,马兜铃酸在玻碳电极上产生不可逆的还原波(Vc,p=-0.51 V vs.Ag/AgCl),具有吸附控制特性.利用马兜铃酸的电化学还原性质建立微分脉冲伏安法测定体系.马兜铃酸浓度在8.0×10-7～6.0×10-6 mol/L范围内与还原峰电流呈良好的线性关系,检出限达1.6×10-8mol/L.测定方法简便灵敏,应用于关木通中马兜铃酸总酸含量的快速测定,结果令人满意.     

呋喃唑酮代谢物单克隆抗体制备及酶联免疫吸附分析方法

本研究针对呋喃唑酮代谢物(AOZ),设计合成了系列半抗原,进一步通过偶联牛血清白蛋白(BSA)免疫Balb/c小鼠、细胞融合、筛选和亚克隆等过程成功获得了源于新颖半抗原H3的具有高亲和力(亲和力常数6.68× 1010L/mol)和高特异性(与其它功能类似物交叉反应小于0.1％)抗AOZ单克隆抗体.同时,基于设计合成的系列同/异源半抗原/包被抗原,考察了不同结构包被原对ELISA方法灵敏度的影响.另外,采用最佳的特征结构异源包被原H5 -OVA,建立了以对硝基苯甲醛(p-NP)为衍生剂的AOZ间接竞争ELISA(icELISA)和直接竞争ELISA(deELISA)检测方法.结果表明:icELISA模式的AOZ检测IC50为0.503 μg/L,定量检测线性范围(IC20～IG80)为0.06～14.0 μg/L,检出限(IC10)达0.017 μg/L; dcELISA模式的AOZ检测IC50为1.19 μg/L,定量检测线性范围为0.14～23.6 μg/L,检出限为0.056 μg/L.两种方法对AOZ的检测灵敏度和定量线性范围均达到相关检测限量要求,可满足不同需求的实际样品检测.     

细交链孢菌酮酸酶联免疫吸附分析方法研究

采用水合肼和乙醛酸依次对细交链孢菌酮酸(Tenuazonic acid,TeA)进行衍生化,设计合成了含有氮杂共轭双键偶联手臂,可增强免疫效果的半抗原TeAHGA.通过偶联载体蛋白BSA后的免疫原TeAHGABSA免疫新西兰大白兔,成功制备了特异性识别TeA水合肼衍生物TeAH的多克隆抗体;优化确立了ELISA最佳反应条件(TeAH-OVA为异源包被原、包被浓度0.156 μg/L、药物稀释及反应缓冲液为PBS、一抗反应时间40 min、二抗反应时间20 min),建立了TeA间接竞争ELISA(icELISA)检测方法,其抑制中浓度(IC50)为1.61 μg/L,检出限(LOD)为0.08 μg/L,定量线性检测范围为0.19～12.89 μg/L (IC20～IC80).番茄、面粉样品平均添加回收率分别为67.2％～89.8％和74.8％～93.7％.     

马兜铃酸的极谱研究

用单扫示波极谱法研究马兜铃酸的电化学行为．在０．１ｍｏｌ／ＬＮａＯＨ底液中，马兜铃酸在－０．８９Ｖ（ｖｓ．ＳＣＥ）产生一良好的二阶导数极谱峰，线性范围为０．０３～３２ｍｇ／Ｌ，检出限为０．０１ｍｇ／Ｌ．用该法测定中药关木通中马兜铃酸含量，结果满意．另外，还研究了马兜铃酸对由邻苯三酚自氧化产生的超氧自由基（Ｏ－·２）的清除作用．     

反相高效液相色谱法测定关木通及配伍中药中马兜铃酸A

为了全面、系统、深入地研究有毒中药关木通,采用乙腈-酸水系统,用反相高效液相色谱法分析关木通及其配伍中药中马兜铃酸A的含量,与文献方法相比,缩短了测定时间,并从总体上降低了分析成本.色谱条件是C18柱,流速1 mL/min.检测波长250 nm.流动相乙腈(水+冰醋酸)=5842.该法精密度高,稳定性好,线性范围为0.07～0.42 μg,回归方程为Y=5.0×106X-32827,相关系数r=0.9999,加样回收率为99.12％.实验结果表明,关木通与生地、当归、大黄、生甘草等中药配伍后,AAⅠ含量均有不同程度的降低,其中以关木通配伍生地组和大黄组最为明显,分别降低了57％和56％.     

反相高效液相色谱法同时测定祛痘类化妆品中的禁用物质

建立了用反相高效液相色谱法(RP-HPLC)同时测定祛痘类化妆品中禁用物质安体舒通、过氧化苯甲酰和维A酸的含量。采用甲醇超声提取,HPLC法分离测定。3种被测物在11 min内均得到良好的分离。在1～200 mg/L范围内其浓度与峰面积呈良好的线性关系(r≥0.9999);在添加质量浓度为1～10 mg/L时,回收率为88.2%～106.7%,相对标准偏差小于3.1%;最低检出限(S/N=3)为安体舒通0.101 μg,过氧化苯甲酰0.100 μg,维A酸0.107 μg。该法简便、快速、准确,可用于祛痘类化妆品中以上3种禁用物质的检测。     

免疫亲和柱净化-柱后光化学衍生-高效液相色谱法同时检测粮谷中的黄曲霉素、玉米赤霉烯酮和赭曲霉毒素A

建立了同时检测粮谷中黄曲霉毒素(B1、B2、G1和G2)、玉米赤霉烯酮和赭曲霉毒素A的免疫亲和柱净化-柱后光化学衍生-高效液相色谱方法.样品经过甲醇-水(体积比为80∶20)提取,通过免疫亲和柱富集和净化,采用Waters Nova-Pak色谱柱(3.9 mm I.d.×150 mm,4 μm),以甲醇、乙腈和1%的磷酸溶液为流动相,梯度洗脱,柱后光化学衍生、改变波长荧光检测.黄曲霉毒素(B1、B2、G1和G2)、玉米赤霉烯酮和赭曲霉毒素A检出限分别为0.24,4.0和0.5 μg/kg,标准曲线的线性范围分别为0.24～6.0,4.0～100.0和0.5～40.0 μg/L;在小麦、玉米、黑麦样品中,平均加标回收率为70.8% ～94.0%,相对标准偏差为2.79% ～9.38%.     

高效液相色谱法测定细辛及其制剂中马兜铃酸A的含量

采用高效液相色谱法对细辛药材及其制剂中的马兜铃酸A进行含量测定。在所建立的条件下,测定马兜铃酸A的线性范围为 0. 019 ~1. 2μg,检出限为 2. 0×10-3 μg,测定结果的相对标准偏差为 3. 99%,回收率为95. 97% ~99. 21%。     

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.     

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.     

Synthesis of N-substituted carbazolones from α-iodo enaminones via Pd(0)-catalyzed intramolecular coupling under microwave irradiation

A variety of N-aryl and N-alkyl carbazolones were conveniently achieved in good to high yields via Pd₂(dba)₃-mediated intramolecular coupling of N-substituted α-iodo enaminones under microwave irradiation. The Pd(0)-catalyzed cyclization was found to proceed favorably with the more electron-deficient phenyl ring during the reactions involving unsymmetrical N,N-diaryl α-iodo enaminones. This unique property enables the construction of carbazolone skeleton containing nitro substituted benzenoid ring.