大鼠服用朱砂后脑内氨基酸类递质含量的变化

研究了朱砂对大鼠脑组织中氨基酸类神经递质含量的影响.将32只Wistar大鼠随机分为低、中、高剂量组和对照组,朱砂灌胃给药14天后,采用高效液相色谱法测定大鼠脑组织中谷氨酸(Glu)、天门冬氨酸(Asp)、甘氨酸(Gly)、γ-氨基丁酸(GABA)和牛磺酸(Tau)的含量,并计算兴奋毒性指数(EI)的变化.与对照组相比较,脑组织中氨基酸类神经递质含量均呈下降趋势,其中Asp和Gly的中、高剂量组差异有统计学意义(P0.05),Tau和GABA的高剂量组有统计学差异(P0.05),Glu和EI所有剂量组均有统计学差异(P0.05).朱砂对氨基酸类神经递质具有一定的抑制作用.     

超高效液相色谱-串联质谱法快速测定大鼠血清中8种神经递质

建立了同时测定8种神经递质(5-HT、GABA、Glu、ACH、NE、DA、5-HIAA和HVA)的超高效液相色谱-三重四极杆质谱方法(UHPLC-MS/MS),并用于大鼠血清样品的测定。大鼠血清经含0.1%甲酸-乙腈沉淀蛋白处理后,选用Waters ACQUITY UPLC BEH C18色谱柱(100 mm×2.1 mm,1.7μm),以0.1%甲酸-乙腈为流动相梯度洗脱进行分离;采用电喷雾离子源(ESI),在正离子扫描下,采用多反应监测模式(MRM)对8种神经递质及内标化合物进行检测。结果表明,8种神经递质可在10 min内准确测定;定量限为1.8 ng/m L,且线性良好,相关系数均大于0.994,日内、日间精密度(n=6)≤9.2%,稳定性、加标回收率和基质效应等均符合分析要求。本方法分析时间短、准确度好、灵敏度高、专属性强、稳定性好、基质效应小,适用于血清中3类(单胺类、氨基酸类和乙酰胆碱)共8种神经递质的同时定量检测。     

3-(4-酮基苯甲酸)-2-喹啉甲醛衍生氨基酸的高效毛细管电泳-激光诱导荧光检测分析

1引言在众多的神经递质中，兴奋性和抑制性氨基酸一直是神经科学中所关注的生化指标。兴奋性氨基酸如谷氨酸（Glu）、天门冬氨酸（Asp）和抑制性氨基酸γ-氨基丁酸（GABA）、甘氨酸（Gly）等在体内具有广泛的生理意义。牛磺酸（Tau）不仅是神经递质，而且具有调节机体的作用。氨基酸在血和脑脊液中的含量较低，大部分氨基酸由于无紫外吸收，在分析过程中常用柱前和柱后衍生氨基酸的方法使之具有紫外或荧光性，3－（4-酮基苯甲酸）－2－喹啉甲醛（CBQCA，3－（4-carboxybenzoyl）－2-quinolinecarbox-aldehyde）为新的柱前氨基酸类衍生…     

中药对大鼠海马区痕量氨基酸神经递质影响的初探

采用激光诱导荧光检测的高效毛细管电泳,结合微透析技术测定灌流3#中药前后大鼠海马区氨基酸类神经递质含量的变化。考察了荧光素异硫氰酸酯(FITC)对氨基酸的衍生条件。在优化条件下,各氨基酸在10-8~10-6 mol/L的浓度范围内与荧光强度呈良好的线性关系,线性相关系数达到0.99以上,检出限低于1.4×10-8 mol/L,适合于对灌流3#中药前后微透析样品中的氨基酸神经递质的测量。测量结果表明:灌流3#药后,抑制性氨基酸γ氨基丁酸(GABA)、甘氨酸(Gly)的浓度有显著地增加。这一结果将对阐明3#中药治疗脑血栓的有关机理提供帮助。     

铜-2,3,4-三羟基-4′-磺基-偶氮苯配合物吸附波的研究

在0.065mol·L~(-1)柠檬酸钠-0.046mol·L~(-1)HCl(pH 6.6)介质中,2,3,4-三轻基-4′-磺基-偶氮苯和铜形成配合物,在单扫描示波极谱仪上于—0.24V(vs.SCE)处产生灵敏的吸附峰,测定铜的浓度范围为0.005～0.3μg·ml~(-1),检出限为0.0025μg·ml~(-1),本法已成功地用于人发及硫酸镍中铜的测定,并进行了电极反应机理研究。     

LC/ESI-MS分离和测定冬虫夏草及其代用品的有效成分

本文报道采用电喷雾离子化(ESI),用高效液相色谱质谱联用法同时分离和测定冬虫夏草及其代用品中主要活性成分尿苷和腺苷的方法。本法使用Shimadzu VP ODS色谱柱,以水甲醇甲酸(90∶9.0∶1.0,V/V)为流动相,2 氯腺苷为内标,选择性离子检测(SIM)模式作定量分析。结果表明:尿苷和腺苷线性范围分别为2.0~110.0μg·mL-1和1.0~120.0μg·mL-1,检出限分别为0.3μg·mL-1和0.2μg·mL-1,标准加入回收率为97.0%~103.3%。该法已成功地用于冬虫夏草及其代用品中尿苷和腺苷的分析。     

生物传感器的研究.V.尿素—石竹花组结电极的研究

尿素—石竹花组织电极是一种植物组织传感器。文中叙述了一种完整石竹花瓣的固定新方法,改善了此类生物传感器的性能:线性范围7.6×10~(-(?))～1.0×10~(-3)mol·L~(-1),斜率47mv·decade~(-1),检测上下限分别为3.2×10~(-3)mol·L~(-1)和4.6×10~(-6)mol·L~(-1),响应时间15～20min,寿命14天.该电极已初步用于实际样品的测定,结果与凯氏法吻合。对尿素含量为3.0×10~(-4)mol·L~(-1)的样品,本法分析结果偏差≤0.2×10~(-4)mol·L~(-1),平均回收率为101.5%(M=3,n=3),表明该传感器具有一定的实用价值。     

川芎嗪对脑缺血下大鼠纹状体区痕量氨基酸类神经递质的影响

采用脑内微透析技术结合激光诱导荧光检测的高效毛细管电泳研究了脑缺血下盐酸川芎嗪注射液对大鼠纹状体区氨基酸类神经递质含量的影响.在优化的分离条件下,各氨基酸在1×10^-6-1×10^-8mol/L的浓度范围内与荧光强度呈良好的线性关系,线性相关系数达到0.99以上,检测限低于1.6×10^-9mol/L,适合于大鼠纹状体区微透析样品中的痕量氨基酸类神经递质的测量.实验结果表明,脑缺血时,使用盐酸川芎嗪注射液可显著降低细胞外兴奋性氨基酸神经递质谷氮酸(G lu)和天门冬氨酸(Asp)的浓度(P<0.05),同时可显著升高抑制性氨基酸神经递质γ-氨基丁酸(GABA)和甘氨酸(G ly)的浓度(P<0.05).这一结果将对阐明盐酸川芎嗪注射液治疗缺血性脑血管疾病的有关机理提供帮助.     

催化氢波-单扫描示波极谱法测定克拉霉素

建立一种灵敏快速测定克拉霉素的新方法。在 0. 24 mol·L-1 KH2PO4 Na2HPO4(pH 6.81)支持电解质中,克拉霉素于-1.57 V(vs.SCE)处产生一催化氢波,其二阶导数峰峰电流与克拉霉素浓度在2.0×10-6~ 1.6×10-4mol·L-1范围内呈线性关系(r=0.999 4,n=8),检出限为1.0×10-6 mol·L-1。10 次测定 1. 0×10-5 mol·L-1 克拉霉素峰电流相对标准偏差为1 8%,回收率在98.3%~100.6%之间。该方法可用于药剂中克拉霉素的测定。     

纯铝中微量钴的极谱测定

钴在1.2×10~(-6)mol·L~(-1)二氮菲-0.02mol·L~(-1)硫脲-6.0×10~(-4)mol·L~(-1)四乙基碘化铵-0.11mol·L~(-1)亚硫酸钠介质(氯化铵-氨水缓冲溶液、pH为9.50)中产生灵敏的极谱催化波;峰电位为-1.68V(vs.SCE),检出限1×10~(-10)mol·L~(-1),钴离子浓度在1×10~(-10)～3×10~(-8)mol·L~(-1)范围内与峰高呈线性关系.体系选择性好,操作简便.用于测定纯铝中1×10~(-7)%以上的钴,重现性好,回收及对照结果满意.     

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%.     

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.