分光光度法测定大黄中总蒽醌

大黄试样经乙醇-水(6+4)溶液回流提取3次,每次0.5 h。以母核1,8-二羟基蒽醌为标准样品,在428 nm测定波长下,采用分光光度法测定大黄中总蒽醌的含量。在优化的试验条件下,1,8-二羟基蒽醌的质量浓度在5.0~25.0 mg.L-1范围内与其吸光度呈线性关系。用此方法测定大黄中总蒽醌含量,加标回收率在98.7%~99.8%之间。     

相溶解度法研究环糊精对蒽醌药物的增溶作用

通过相溶解度法,测定1,2-二氨基蒽醌、1,4-二氨基蒽醌和1,8-二羟基蒽醌在不同温度、不同浓度的β-环糊精(β-CD)、羟丙基-β-环糊精(HP-β-CD)以及羟乙基-β-环糊精(HE-β-CD)中的溶解度,绘制相溶解度曲线,并进行回收率及稳定性实验.实验结果表明:1,2-二氨基蒽醌、1,4-二氨基蒽醌和1,8-二羟基蒽醌的溶解度均随3种环糊精浓度的增加而呈线性增加,相溶解度曲线为AL型,蒽醌与环糊精形成的包合物类型为1∶1型,3种环糊精对蒽醌均有增溶作用,增溶效应顺序为HP-β-CDHE-β-CDβ-CD,与HP-β-CD作用顺序为1,2-二氨基蒽醌1,4-二氨基蒽醌1,8-二羟基蒽醌.     

蒽醌衍生物与β-胡萝卜素自由基抗氧化协同作用的研究

在均相体系中利用紫外光谱法,研究了偶氮二异丁睛(AIBN)引发的亚油酸(LH)过氧化反应,发现蒽醌(AQ)、1,2-二羟基-9,10-蒽醌(AQ1,2-OH)、1,8-二羟基-9,10-蒽醌(AQ1,8-OH)和β-胡萝卜素(β-C)对LH过氧化均有抑制作用,并表现出协同效应．膨胀计法研究表明AQ,AQ1,2-OH,AQ1,8-OH和β-C对AIBN引发的苯乙烯自由基本体聚合均有阻聚作用,并发现AQ,AQ1,2-OH和AQ1,8-OH与β-C间存在明显的协同阻聚作用．     

1,8-二羟基-9,10-二氢蒽的合成

以1,8-二羟基蒽醌为原料,经甲醚化,锌粉和金属钠还原,去甲基等4步反应合成1,8-二羟基-9,10-二氢蒽,总产率为37.1,8-二甲氧基蒽醌用NaBH₄/CF₃COOH还原生成二聚产物,并测定了其单晶结构.     

三种羟基蒽醌类药物与溶菌酶的作用及其构效关系研究

在模拟人体生理条件下,利用紫外光谱法、荧光光谱法和同步荧光光谱法结合研究三种羟基蒽醌类药物(1,2-二羟基蒽醌、1,4-二羟基蒽醌和1,8-二羟基蒽醌)与溶菌酶(LYSO)相互作用机制,并探讨其构效关系。紫外结果初步显示,三种羟基蒽醌类药物与LYSO发生相互作用。荧光结果进一步证实三种羟基蒽醌类药物均与LYSO发生结合,且对LYSO的荧光猝灭机制均为静态猝灭并伴随有非辐射能量转移。三种羟基蒽醌类药物与LYSO均存在一个结合位点,它们与LYSO形成1∶1复合物,在303K下,结合常数K分别为8.47×105、4.88×105和5.43×105L·mol-1,结合距离r分别为5.83、5.12和5.14nm,与溶菌酶作用后焓变分别为-41.2、-87.6和-39.0 kJ·mol-1,熵变分别为-22.4、-180和-19.1 J·mol-1·K-1。三种羟基蒽醌类药物与LYSO的作用力均为范德华力和氢键,且作用强弱不同,其顺序为:1,2-二羟基蒽醌1,8-二羟基蒽醌1,4-二羟基蒽醌。同步荧光法结果表明三种羟基蒽醌类药物与LYSO相互作用后均导致LYSO构象发生改变。研究结果表明,蒽醌环上羟基位置的不同对羟基蒽醌类药物与溶菌酶结合强弱有较大程度的影响。     

中药大黄蒽醌类物质电喷雾质谱裂解规律研究

大黄是一味临床常用药材,化学成分复杂,主要药效成分为蒽醌类衍生物.其中1,8-二羟基蒽醌类衍生物如大黄素(Emodin)、大黄酚(Chrysophanol)、大黄酸(Rheni)、大黄素甲醚(Physcion)、芦荟大黄素(Aloe-emodin)等在中药中分布较广泛.这类物质及其甙类具有泻下、抗菌、抗癌等多种生理活性.对于大黄蒽醌类物质的分离、含量测定、药理研究等一直是一个非常活跃的领域,但对大黄蒽醌类衍生物的电喷雾质谱裂解规律的研究还未见报道.本文我们应用电喷雾离子阱质谱(ESI-MS)研究了5种大黄素型蒽醌衍生物的裂解规律.为进一步开展大黄蒽醌类物质在生物体内的代谢规律等做了有益的探讨.     

并联式双三元高效液相色谱系统快速检测土壤中6种蒽醌类化合物

建立了用于住宅建设污染土壤中1,8-二硝基蒽醌、1,5-二硝基蒽醌、1-氨基蒽醌、蒽醌、萘、1,4,5,8-四氯蒽醌等6种蒽醌类化合物含量的高效液相色谱分析方法。利用Ultimate双三元液相色谱仪的特点,设计了一套并联式双系统,采用2根相同的色谱柱(Dikma Diamonsil C18)交叉分析,节省了41.46%的分析时间。以50 mL N,N-二甲基甲酰胺-1,4-二氧六环-甲醇(5:20:25, v/v/v)为萃取剂,采用超声波辅助方法提取样品中的6种目标物。6种目标物的平均加标回收率为82.7%～101%,相对标准偏差为1.8%～3.2%,检出限(以信噪比为3计)为0.007～0.054 mg/kg,可满足北京地方标准DB11/T 811-2011的限量要求。该方法简便、准确,并能节省检测时间,有良好的重现性,可用于土壤中蒽醌类化合物的检测。     

硝基蒽醌异构体的高效液相色谱分析

一、前言军装草绿(咔叽-2G)和警蓝(S-BGL和2BLN)染料的重要中间体为硝基蒽醌,前者为α-硝基蒽醌(简写α-NO_2AQ)后者为1,5-和1,8-二硝基蒽醌(1,5-(NO_2)_2AQ和1,8-(NO_2)_2AQ)。蒽醌的硝化过程及其产物非常复杂。产物的分析虽有柱色谱、薄层色谱和纸色谱等方法,但分析速度较慢,误差也较大,不能及时提供硝化过程数据,做为选择合理硝化工艺条件以提高质量和控制质量的依据。蒽醌硝化产物理论上应有12个异构体     

光度法快速测定不锈钢中的铬、镍、钼、钛、锰

试样用等体积硝酸和盐酸混合酸溶解,用高氯酸将Cr(Ⅲ)氧化为Cr(Ⅵ),用定量Fe(Ⅱ)将Cr(Ⅵ)定量还原为Cr(Ⅲ),用铬酸"剩余光度法"测定铬,丁二酮肟光度法测定镍,硫氰酸盐光度法测定钼,变色酸(1,8-二羟基萘-3,6-二磺酸)光度法测定钛,高锰酸光度法测定锰。测定结果与标准值基本一致,铬、镍、钼、钛、锰测定结果的相对标准偏差分别为0.2%、0.3%、1.5%、2.0%、2.0%。     

2,3,4,9-四氢-9-羟基-1,10-蒽醌的合成及荧光猝灭法测定痕量砷

荧光动力学分析法常以罗丹明类、荧光素类、桑色素等作为指示物,用蒽醌作为指示物较少见。本文报道了以2,3,4,9-四氢-9-羟基-1,10-蒽醌(简称R)为指示物,荧光动力学分析法测定痕量砷的新方法。实验直接用硼酸代替三氯化铝加硫酸封环一步法制得1,4-二羟基-9,10-蒽醌,再经冰醋酸和     

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.