菊苣酸在高效液相色谱测定过程中与流动相中银离子配位的探讨

菊苣酸是紫锥菊属植物中的一种水溶性酚酸类化合物.本研究对紫锥菊提取物中菊苣酸检测的条件是:流动相为V(乙腈)∶ V(去离子水)=38∶ 62(含0.8%冰醋酸和8 mmol/L AgNO3);色谱柱为Restek Pinnacle 11 C18柱(250 mm×4.6 mm, 5 μm);流速为0.5 mL/min;进样量为10 μL;检测波长为326 nm.实验发现,在流动相中添加AgNO3后可以明显改善菊苣酸测定效果,提高分离度,并有效除去其它杂质成分的干扰, r大于0.99;检出限为8～40 mg/L,此方法的相对标准偏差小于3.0%;平均回收率为98.5%,方法符合测试要求.AgNO3改善分离效果的原因可能为菊苣酸和Ag 之间存在一定的配位作用,改变了菊苣酸的性质,扩大了与杂质成分的结构差异,从而使测定更准确,同时用红外和紫外光谱辅助解释了可能的配位机理和配位点.     

紫锥花种属中酚类化合物的HPLC分析

本文报道了一种测定紫锥花草药中咖啡酸、对羟基苯甲酸、对-香豆酸、原儿茶酸、丁香酸、阿魏酸、香草酸、咖啡奎尼酸、洋蓟酸、菊苣酸和紫锥花苷等11种酚类化合物的高效液相色谱分析方法。本法可应用于各种紫锥花草药中酚类化合物的测定。结果表明,在紫锥菊种属中含量最多的酚类化合物是菊苣酸、咖啡奎尼酸和紫锥花苷;在狭叶紫锥菊种属中含量较丰的是紫锥花苷和菊苣酸;而在白花紫锥菊种属中则以紫锥花苷以含量较多。     

高速逆流色谱制备分离紫甘薯花色苷

采用高速逆流色谱法分离纯化紫甘薯花色苷.以正丁醇-乙酸乙酯-0.5%乙酸(3:1:4,V/V)为溶剂体系,上相为固定相,下相为流动相,流速2mL/min,进样量300mg,分离得到两种花色苷的混合物;混合物再以0.2%三氟乙酸-正丁醇-甲基叔丁基醚-乙腈(6:5:2:1,V/V)为溶剂体系,上相为固定相,下相为流动相,...     

高速逆流色谱法分离紫锥菊花色苷及其抗氧化性研究

建立了高速逆流色谱(HSCCC)分离制备紫锥菊花色苷类化合物的方法,并对所获得的2个花色苷单体进行了体外抗氧化性实验。以新鲜紫锥菊花瓣为原料,含0.1%HCl的60%乙醇为溶剂避光冷浸提取,经乙酸乙酯萃取和D101大孔吸附树脂(100 mL,2 cm×30 cm)纯化后,得2.1 g紫锥菊花色苷提取物干粉样品。以水-正丁醇-甲基叔丁基甲醚-乙腈-三氟乙酸(6∶3∶2∶1∶0.001)为HSCCC分离溶剂系统,上相为固定相,下相为流动相,流速2.0 mL/min,进样量160 mg,通过一次分离得到2种花色苷单体化合物,经HPLC检测其纯度分别达95.1%(9.8 mg)、98.2%(14.3 mg),MS及NMR技术鉴定其结构分别为矢车菊素-3-O-β-D葡萄糖苷(化合物1)和矢车菊素-3-O-(6″-O-丙二酰-β-D葡萄糖苷)(化合物2)。以Vc为对照组,对所获得的2种花色苷单体化合物进行了1,1-二苯基-2苦肼基(DPPH.)体外抗氧化性能评价,结果显示2种花色苷对DPPH.的半清除率(EC50)均小于10 mg/L,小于对照样Vc,表明2种花色苷均具有较强的自由基清除作用,且化合物1的清除能力强于化合物2。     

HPLC法同时测定松果菊属中4种酚类化合物

松果菊属(Echinacea Moenck.)是原产于美洲的一类菊科野生花卉,也称“紫锥菊”。该属植物共有8种及数个变种,均为多年生草本,其中已开发为药品者主要为淡紫松果菊(E.palli-a)、狭叶松果菊(E.angustifolia)及紫花松果菊(E.purpurea)[1]。松果菊属植物主要用于促进机体的免疫功能     

高效液相色谱法同时测定复方南板蓝根片中秦皮乙素和菊苣酸

建立高效液相色谱同时测定复方南板蓝根片中秦皮乙素和菊苣酸含量的方法。采用XBridge C₁₈色谱柱(250 mm×4.6 mm,5μm)分离，流动相为乙腈-0.3%磷酸溶液，梯度洗脱，流量为1 mL/min，检测波长为330 nm，柱温为40℃，进样体积为10μL，以色谱峰面积外标法定量。秦皮乙素和菊苣酸的质量浓度分别在18.40～184.02、4.96～49.61 g/mL范围内与色谱峰面积的线性关系良好，相关系数均为0.999 9。秦皮乙素、菊苣酸测定结果的相对标准偏差分别为0.72%、0.54%(n=6)，平均回收率分别为97.40%、98.45%。该方法操作简单，重复性好，准确度高。     

高效液相色谱法测定农药中三氟氯菊酸的含量

提出了高效液相色谱法测定农药中三氟氯菊酸含量的方法。样品以甲醇超声提取,所得提取液以Agilent Eclipse XDB-C18色谱柱为分离柱,以甲醇与磷酸(0.5+99.5)溶液以体积比55比45组成的混合液为流动相,在检测波长230nm处进行测定。三氟氯菊酸质量浓度在0.025~0.5g·L-1范围内与其峰面积呈线性关系,方法检出限(3S/N)为0.112mg·L-1。加标回收率在97.5%~98.1%之间,测定值的相对标准偏差(n=6)小于2%。     

Separation of Anthocyanins in Echinacea Purpurea Flower by High Speed Counter-current Chromatography and the Research on the Antioxidant Activity of the Anthocyanins

建立了高速逆流色谱(HSCCC)分离制备紫锥菊花色苷类化合物的方法,并对所获得的2个花色苷单体进行了体外抗氧化性实验.以新鲜紫锥菊花瓣为原料,含0.1％ HCI的60％乙醇为溶剂避光冷浸提取,经乙酸乙酯萃取和D101大孔吸附树脂(100 mL,2 cm×30 cm)纯化后,得2.1g紫锥菊花色苷提取物干粉样品.以水-正丁醇-甲基叔丁基甲醚-乙腈-三氟乙酸(6∶3∶2∶1∶0.001)为HSCCC分离溶剂系统,上相为固定相,下相为流动相,流速2.0 mL/min,进样量160 mg,通过一次分离得到2种花色苷单体化合物,经HPLC检测其纯度分别达95.1％ (9.8 mg)、98.2％( 14.3 mg),MS及NMR技术鉴定其结构分别为矢车菊素-3-O-β-D葡萄糖苷(化合物1)和矢车菊素-3-O-(6″-O-丙二酰-β-D葡萄糖苷)(化合物2).以Vc为对照组,对所获得的2种花色苷单体化合物进行了1,1-二苯基-2苦肼基(DPPH·)体外抗氧化性能评价,结果显示2种花色苷对DPPH·的半清除率(EC50)均小于10 mg/L,小于对照样Vc,表明2种花色苷均具有较强的自由基清除作用,且化合物1的清除能力强于化合物2.     

pH区带逆流色谱法分离纯化马钱子中马钱子碱和士的宁

建立了pH区带逆流色谱分离制备马钱子中生物碱类成分马钱子碱和士的宁的方法。溶剂系统为V(甲基叔丁基醚):V(乙腈):V(水)=2:2:3,静置分层后,上相加入三乙胺,使其浓度为10mmol/L,作为固定相;下相加入HCl,使其浓度为10mmol/L,作为流动相。从308mg马钱子总生物碱中分离得到50mg马钱子碱和120mg士的宁,得率分别为72.8%和85.1%;纯度分别为96.8%和98.3%。并采用LC-ESI-MS和13CNMR对目标化合物的结构进行了鉴定。     

加压毛细管电色谱在芎菊上清片中栀子苷及黄芩苷分离检测中的应用

采用加压毛细管反相电色谱技术,建立了一种用于分离检测芎菊上清片中栀子苷和黄芩苷的高效简便新方法。色谱柱为EP-100-20/45-3 C18毛细管柱(总长度45 cm,有效长度20 cm,直径为100μm,ODS填料内径3μm),柱温为25℃,流动相采用20 mmol/L Na H2PO4-乙腈(71∶29),流动相的总流速为0.035m L/min,分离电压为+2.0 k V,检测波长为240 nm。经等度洗脱,栀子苷和黄芩苷可实现快速分离,峰面积的相对标准偏差(RSD)不大于2.8%,回收率为91.9%~101.2%,测得该芎菊上清片中栀子苷的含量为2.616 mg/g,黄芩苷的含量为11.220 mg/g。该方法的选择性好、柱效高、试剂用量少,用于芎菊上清片中黄芩苷和栀子苷的分离检测,结果满意。     

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.     

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%).     

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.     

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.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.