制备型高效液相色谱法分离纯化川西獐牙菜提取物中的龙胆苦苷

龙胆苦苷(GPS)是龙胆类药材及其相关制品质量控制的指标成分。本研究利用制备型高效液相色谱从川西獐牙菜提取物中分离纯化龙胆苦苷对照品。对制备色谱的流动相组成、流速、进样量和检测波长等制备参数进行了优化。采用的色谱柱为C18柱(200 mm×50 mm, 5 μm),流动相为甲醇和0.1%乙酸水溶液(体积比为30:70),流速为75 mL/min,检测波长为254 nm,进样体积为500 μL。在30 min的运行时间内,龙胆苦苷与其他干扰成分得到了很好的分离,产品纯度达到了99%以上。此方法具有快速高效、产品纯度高的特点,可用于制备龙胆苦苷对照品和对龙胆苦苷制品的质量控制。     

青藏高原龙胆属中10种野生药材的4种主要活性成分的测定分析

建立反相高效液相色谱法同时测定青藏高原龙胆属中10种常用野生药材的獐牙菜苦苷、龙胆苦苷、獐芽菜苷、异荭草苷的含量.方法:采用反相高效液相色谱法.乙腈-水(0.1%的H3PO4)为流动相,梯度洗脱,洗脱条件为0.01 min→20.00 min→20.01 min→40.00 min→40.01 min→50.00 min,乙腈:12%→12%→15%→33%→100%→100%,体积流量1.0 mL/min,检测波长为240 nm,柱温25 ℃.4种成分均达到基线分离,线性良好.     

高速逆流色谱法从秦艽地上部分制备分离龙胆苦苷

采用高速逆流色谱法分离纯化秦艽地上部分中的龙胆苦苷。溶剂系统为V(氯仿)∶V(甲醇)∶V(水)=4∶4∶2,上相为固定相,下相为流动相,转速为800r/min,流速为2mL/min。所得产物经LC-MS分析为龙胆苦苷,纯度经高效液相色谱分析为94.0%(峰面积归一化法)。在保证分离效果的前提下,增大进样量,摸索制备分离龙胆苦苷的高速逆流色谱条件,为用高速逆流色谱法大量制备龙胆苦苷提供了一个可行方法。     

女贞子中红景天苷的HPLC制备分离

研究了制备型高效液相色谱分离纯化女贞子中红景天苷的方法。制备色谱的参数为:色谱柱为C18柱(50 mm×200 mm,5μm),流动相为甲醇-水(体积比为7.5∶92.5),流速100 mL·min-1,二级管阵列检测器在278 nm检测,进样体积为2.2 mL。在18 min的运行时间内,红景天苷与干扰成分得到很好的分离,经HPLC检测纯度均达到98%以上。此方法具有快速高效、分离组分纯度高的特点,可用于制备红景天苷。     

藏药麻花艽中四种苦苷类化学成分的HPLC测定

建立了藏药麻花艽中龙胆苦苷(gentiopicroside)、落干酸(loganic acid)、獐牙菜苦苷(swertiamarin)和獐牙菜苷(sweroside)4种苦苷类成分的HPLC分析方法。色谱柱为Eclipse XDB-C8(4.6 mm i.d.×150 mm,5μm),流动相为体积分数5%乙腈 10 mmoL甲酸~95%乙腈水溶液,检测波长为240 nm。结果表明,该方法具有良好的线性关系和回收率,为麻花艽中苦苷类成分的进一步开发利用提供了科学依据。     

HPLC测定云雾龙胆花中獐牙菜苷和异荭草苷的含量

建立云雾龙胆花中獐牙菜苷和异荭草苷含量测定的HPLC方法。采用微波辅助动态回流法进行提取,色谱条件:Fusion-RP 80 A C18柱(150×4.6 mm,5μm);流动相:甲醇-0.2%磷酸溶液梯度洗脱(0~20 min∶18∶82~30∶70;20~30min∶30∶70~40∶60;30~35min∶40∶60~50∶50);流速:1 mL/min;柱温:30℃;检测波长254 nm。云雾龙胆花中獐牙菜苷和异荭草苷的色谱峰与共存组分完全达到基线分离,线性范围分别为0.25~1.25μg(r=0.9998),0.432~2.160μg(r=0.9999),平均加样回收率分别为97.7%(RSD=0.84%),99.2%(RSD=0.76%)。     

高效液相色谱法同时测定葛枳胶囊中5种有效成分的含量

提出了高效液相色谱法同时测定葛枳胶囊中5种有效成分(葛根素、大豆苷、甘草苷、大豆苷元和甘草酸)的含量。样品经甲醇-水(50+50)溶液超声提取30min,采用Diamonsil C18色谱柱(200mm×4.6mm,5μm)为分离柱,以不同体积比混合的乙腈和磷酸(0.1+99.9)混合液为流动相进行梯度洗脱,甘草苷的检测波长为276nm,其余4种成分均为250nm。5种有效成分分别在一定的质量浓度范围内与其峰面积呈线性关系,方法的检出限(3S/N)在0.050～0.338mg·L-1之间。方法的回收率在97.1%～104%之间,测定值的相对标准偏差(n=6)在1.0%～2.7%之间。     

高效液相色谱法同时测定舒胆片中栀子苷、虎杖苷、柚皮苷和新橙皮苷

建立同时测定舒胆片中栀子苷、虎杖苷、柚皮苷和新橙皮苷含量的高效液相色谱法.选择Kromasil 100–5–C18柱(4.6 mm×250 mm,5μm)为分离柱,以乙腈–水为流动相,梯度洗脱,流量为1.0 mL/min,柱温为30℃,检测波长:0～13 min时为238 nm,13～17 min时为306 nm,17...     

藏药达乌里秦艽中环烯醚萜苷的HPLC测定

采用HPLc法同时测定了藏药达乌里秦艽中龙胆苦苷(gentiopicroside)、獐牙菜苦苷(swertiamarin)、獐牙菜苷(sweroside)和落干酸(loganic acid)4种主要环烯醚萜苷类成分,利用在线质谱(MS)进行了定性分析,并与同属藏药麻花艽进行了比较.色谱柱为Eclipse XDB-C8(4.6 mm×150 mm i.d.,5 μm),流动相A:体积分数5%乙腈(含10 mmol甲酸)水溶液,流动相B:体积分数95%乙腈水溶液,以流动相A在0～15 min内由100%线性减至90%,15～20 min内保持90%不变线性梯度洗脱.流速1.0 mL/min,检测波长240 nm,柱温30℃.结果表明,4种成分均达到了基线分离,具有较好的线性关系和回收率.本法可作为达乌里秦艽药材有效成分的测定方法,为其有效成分的进一步开发利用提供依据.     

高效液相色谱法分析谷氨酸棒杆菌细胞内尿苷二磷酸葡萄糖和尿苷二磷酸半乳糖

建立了利用高效液相色谱分离分析谷氨酸棒杆菌细胞内尿苷二磷酸(UDP)葡萄糖与UDP半乳糖的新方法,考察了不同色谱柱、不同分离模式及不同流动相组成对UDP葡萄糖和UDP半乳糖的保留特性及分离度的影响。结果表明,在Zorbax NH2柱(250 mm×4.6 mm i.d.,5 μm)上以0.125 mol/L KH2PO4缓冲液(pH 3.6)-乙腈(体积比为40∶60)溶液为流动相,可使谷氨酸棒杆菌细胞内的两种中间代谢产物UDP葡萄糖与UDP半乳糖在22 min内达到基线分离。该方法对UDP葡萄糖和UDP     

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%.     

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.     

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.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Copper catalyzed/mediated synthetic methodology for ebselen and related isoselenazolones

Scope of the copper catalyzed/mediated selenium-nitrogen coupling reaction has been studied for the synthesis of isoselenazolones. It is noticed that the 2-chloro, 2-bromo-, and 2-iodo-aryl amides substrates can be exploited in the selenium-nitrogen coupling reaction by employing 25-100 mol % of CuI/1,10-phenanthroline (L) and potassium carbonate as a base in DMF. Furthermore, electron rich 2-chloro-arylamides also underwent selenium-nitrogen coupling reaction to give biologically important selenium-nitrogen heterocycles. Also, copper-catalyzed selenium-nitrogen coupling reaction has been meticulously applied for the synthesis of diaryl diselenides having methoxy, amine, and amide functionality from respective aryl iodides in the presence of stoichiometric amount of succinimide as an external Se-N coupling partner.     

Knoevenagel condensation catalyzed by novel Nmm-based ionic liquids in water

A series of novel N-methyl morpholine (Nmm) based ionic liquids with 1,2-propanediol group were synthesized and used as catalysts for Knoevenagel condensation at room temperature in water. Under the effect of the catalyst, various aldehydes or aliphatic ketones could react with a wide range of activated methylene compounds well, including malononitrile, alkyl cyanoacetate, cyanoacetamide, β-diketone, barbituric acid, 2-arylacetonitrile and thiazolidinedione. Furthermore, most of the products could be separated just by filtrating and washing with water. Additionally, the catalyst is recyclable and applicable for the large-scale synthesis.     

Construction of polyheterocyclic spirotetrahydrothiophene derivatives via sulfa-Michael/aldol cascade reaction

A series of polyheterocyclic spirotetrahydrothiophene derivatives were obtained in moderate to excellent yields via a catalyst-free sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 under mild conditions. We also present the first asymmetric sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 with moderate to good enantioselectivities catalyzed by readily available chiral phase-transfer catalysts (PTCs).     

Suzuki-Miyaura reactions of the soluble guanylate cyclase inhibitor NS2028: a non-product specific route to C-8 substituted analogues

Both soluble guanylate cyclase (sGC) inhibitors ODQ 1 and NS2028 2 are synthesized via improved protocols. In the former case treating 3,4-dihydroquinoxalin-2(1H)-one oxime 8, which can be prepared in two steps from 1,2-benzenediamine, with 1,1′-carbonyldiimidazole (CDI) gives the dihydro-ODQ 10 that in the presence of KMnO₄ oxidises to give ODQ 1 in an overall yield of 46% starting from 1,2-benzenediamine. In the latter case, the synthesis affords NS2028 2 from 2-amino-4-bromophenol 3 in three steps with an overall yield of 85% and avoids the need for chromatography. Furthermore, Suzuki-Miyaura reaction conditions are described that enable the preparation of 8-aryl and 8-heteroaryl derivatives of NS2028 directly from NS2028 2. Finally, demethylation of the 8-(methoxyphenyl) substituted analogues afforded the 8-(hydroxyphenyl) derivatives 40-42. All new products are fully characterised.