芪麦口服液锗元素测定

芪麦口服液是广西中医学院药剂科用中药配制成具有补气补血,提高机体免疫力的药剂。测定了该药中锗元素的含量。     

麦斛细胞毒活性成分研究

利用硅胶、聚酰胺柱层析等分离方法, 从麦斛全草的乙醚萃取物中分离得到4个化合物, 经化学方法和光谱分析(UV, IR, NMR, MS)鉴定为3,4,7-三羟基-2-甲氧基菲(1), 2,5-二羟基-4-甲氧基菲(2), eugenitin (3)和2,5-二羟基-4-甲氧基-9,10-二氢菲(4), 其中1为新化合物. 采用MTT法分别测得化合物1和2对体外培养的人急性髓性白血病细胞和人肝癌细胞增殖的抑制活性, 并分别考察了增敏剂葛根素对化合物1和2增殖活性的协同作用.     

化学改性麦壳对孔雀绿的吸附作用

通过不同的化学方法对农业副产物麦壳进行改性,以制得廉价的生物吸附剂,并分别研究了它们对孔雀绿的吸附性能。结果表明,天然麦壳对孔雀绿有一定的吸附量,经化学修饰后对孔雀绿的吸附量有不同程度的提高,其中,经硝酸酸化后的麦壳对孔雀绿的吸附效果最好。通过研究硝酸改性麦壳吸附孔雀绿条件的影响发现,吸附40min达到平衡;随初始浓度增加,吸附量增大;溶液在中性或碱性范围内,吸附量较高;吸附符合Langmuir和Freundlich等温模型,吸附动力学过程可以用准二级动力学方程来较好地拟合。因此,硝酸改性麦壳可以用于有效去除水体中的孔雀绿。     

离子交换剂在麦胚凝集素制备中的应用

本文采用D261、001×7、DEAE—Cellulose—32和CM—Cellulose—32离子交换剂进行柱层析,去除麦胚提取液中褐色、红色、黄色、绿色、黑色等色素物质及杂蛋白。所制备的麦胚凝集素(Wheat Germ agglutinin简称WGA,下同),凝血活性高于Sigma公司产品,对等体积2％人A型红血球最小凝集剂量是4μg/ml。WGA是一种同工凝集素,其等电点分别是pH5.9、pH6.2、pH6.8,经SDS—PAGE检测它们的表观分子量分别是15KD、18KD和36KD。     

改性麦壳对水中苯酚的生物吸附作用

通过对农业副产物麦壳进行甲醛甲酸甲基化改性,研究了改性后麦壳对苯酚的吸附情况,讨论了吸附时间、吸附剂用量、初始浓度、温度及pH等条件对吸附效果的影响。结果表明,改性后的麦壳对苯酚的吸附反应迅速,随着吸附剂用量增加,吸附量增大;增大初始浓度,吸附量升高;升温对反应不利;酸性条件下有利于吸附。改性后的麦壳对苯酚的吸附符合Langmuir和Freundlich等温模型。改性麦壳可用于苯酚的去除。     

高效液相色谱法测定植物油中麦固醇的含量

采用高效液相色谱法测定植物油中麦固醇的含量。试验优化了提取油脂混合物添加的麦固醇的工艺因素:最佳提取次数为4次;离心转速为2 000r·min-1;皂化温度为80℃;皂化时间为3.5h。用C18反相色谱柱为分离柱,以甲醇-水(98.5+1.5)溶液为流动相,检测波长为210nm,麦固醇的质量浓度在12.5~1 000mg·L-1范围内与峰面积呈线性关系,方法的检出限(3S/N)为5mg·L-1。加标回收率在86.2%~98.7%之间,测定值的相对标准偏差(n=6)在2.4%~3.9%之间。     

麦胚凝集素亲和色谱富集糖肽过程中的肽键裂解

蛋白质的糖基化是最重要的翻译后修饰之一,与蛋白质结构和功能的关系密切。凝集素亲和色谱是蛋白质糖基化研究中很常用的工具,不同的凝集素可以对不同的单糖或寡糖有特异的富集作用。麦胚凝集素（WGA）由于其特异作用的糖型广泛存在而成为使用最多的凝集素之一。在本研究中,发现将WGA用于糖肽亲和富集会导致部分肽段的降解,从而导致后续的肽段序列分析的失败。本文用4种标准蛋白质对这种现象进行了验证,结果表明肽段的降解可以发生在多个位点,其中较多地发生在酪氨酸、苯丙氨酸及亮氨酸的羧基端。这一结果提示：在糖蛋白质组研究中,如果应用WGA富集糖肽并采用质谱进行鉴定,则采用半酶切或非特异性酶切的检索策略更为合适。     

麦壳对水溶液中铜离子的动态吸附研究

对麦壳柱吸附铜离子的动态实验进行了研究。pH为5时有利于吸附,Na+和Ca2+的存在不利于吸附,说明在吸附过程中存在离子交换机理。溶液流速、溶液浓度对流出曲线有较大的影响。吸附后的麦壳用0.5mol/L盐酸再生,能重复使用。对不同流速和不同浓度的流出曲线用Thomas和Yoon-Nelson线性模型进行了拟合,并预测了流出曲线。结果表明,饱和吸附量随着初始浓度的增大而增大,随流速的增加而减小;穿透时间随初始浓度和流速的增大均减小。在不同条件下的线性相关系数为0.920～0.948,说明Thomas和Yoon-Nelson模型都可用于描述穿透曲线。     

高效毛细管电泳法测定麦当乳通颗粒剂中阿魏酸

提出了用高效毛细管区带电泳法(CZE)测定中成药麦当乳通颗粒中阿魏酸含量的方法.电泳分离在控温18 ℃的无表面涂层的熔质石英毛细管中进行.以12.5 mmol·L-1硼砂缓冲液(pH 8.20)为运行缓冲溶液,压力进样(6kPa×3 s),检测波长为200 nm.在1～52 mg·L-1质量浓度范围内呈线性(r=0.999 9),回收率为98.77%,RSD为1.9%,日内和日间的相对标准偏差分别为1.9%和1.6%.     

麦粒状PbF2材料的制备与表征

用乳液法制备了α-PbF₂材料。用粉末X射线衍射(XRD)、透射电子显微镜(TEM)和扫描电子显微镜(SEM)等对所制备产物的结构和形态进行了表征。实验结果表明合成产物的形状为麦粒状, 其直径为400～500 nm，长度为1 500～4 000 nm。产物形貌规整，分散性好，尺寸可控，在室温下有优良的荧光性质。     

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%.     

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.     

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.     

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.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

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.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.