示波极谱法测定葡萄籽提取物中原花青素

提出了测定葡萄籽提取物中原花青素的电化学分析新方法。在碱性硼砂底液中,原花青素与Zn(Ⅱ)在(-1.02±0.02V)(vs.SCE)电位处产生灵敏络合吸附波。其峰电流IP与原花青素在40～200mg·L-1范围内呈良好的线性关系,方法的检出限为25mg·L-1。该方法已用于保健食品中原花青素的含量测定,重现性好,结果满意。     

流动注射-抑制化学发光法测定葡萄籽提取物中原花青素

基于在碱性条件下,原花青素对H2O2-Luminol体系有显著的抑制作用,结合反相流动注射技术,首次建立了流动注射-抑制化学发光测定葡萄籽提取物中原花青素的含量;原花青素质量浓度在O．2～20．Omg／L范围与相对发光强度呈线性关系,检出限为O.lmg／L,采样频率为140次／h,对lO．Omg／L的原花青素平行测定11次,其RSD为1．2％,回收率为97％～103％;该方法用于原花青素的测定,结果令人满意。     

间接原子吸收法测定葡萄籽提取物中的原花青素

提出了间接测定葡萄籽提取物中原花青素的原子吸收光谱法。它是基于原花青素能与醋酸铜发生络合反应,生成难溶于水的棕黄色沉淀,经离心分离后,用原子吸收法测定上清液中过量的铜离子,可间接测定原花青素的含量。方法线性范围为3．0-30．0mg／L;RSD为1．1％-1．2％;回收率为98.9％-102.0％。     

原子吸收法间接测定葡萄籽提取物中的原花青素

建立了间接测定葡萄籽提取物中原花青素的原子吸收光谱法。它是基于原花青素能与碱式乙酸铅发生配合反应,产生难溶于水的棕黄色沉淀,经干过滤分离后,用原子吸收法测定滤液中过量的铅离子,可间接测定原花青素。方法线性范围为8.0～80.0μg/mL,回收率为98.1%～102.2%。     

硫酸高铈铵分光光度法测定葡萄籽提取物中原花青素

建立了葡萄籽提取物中原花青素测定的新方法 硫酸高铈铵分光光度法。它是基于原花青素与Ce4 在强酸性介质中反应生成无色的Ce3 ,通过测定黄色高铈盐的吸光度,间接测定原花青素,Ce4 在319nm波长处具有最大吸收。该方法的线性范围为0.12～10μg mL,RSD为0.98%～1.1%,回收率为97.2%～102.8%,相关系数r=0.9992,检出限为0.04μg mL。     

KMnO4分光光度法测定葡萄籽原花青素

建立了葡萄籽提取物中原花青素测定的新方法-KMnO4分光光度法.基于原花青素结构中含有还原性基团,能在强酸性介质中与KMnO4发生氧化还原反应,在545 nm吸光度值减少而在310 nm处吸光度值增加,通过A310/A545的比值来测定原花青素.该方法的线性范围为1.6～3.6 μg/mL,RSD为0.13%～0.4%,回收率为95.2%,相关系数r=0.9996,检出限为0.03 μg/mL.     

大孔吸附树脂对葡萄籽原花青素的吸附研究

对8种大孔吸附树脂对葡萄籽原花青素的吸附洗脱性能进行了筛选实验，并选择其中几种树脂研究其对葡萄籽原花青素的吸附特性及机理，发现NKA树脂是比较好的吸附剂。     

藤三七中一个新黄烷醇和抗HIV活性成分

利用各种色谱(硅胶和凝胶)方法, 从藤三七[Boussingaultia gracilis Miers var. pseudobaselloides Bailey]的70%(体积分数)的乙醇提取物中分离得到2个黄烷醇类化合物(1, 2)和4个黄酮类化合物(3~6). 采用UV, IR, MS 和1D, 2D NMR方法, 分别鉴定出如下化合物: 7-羟基-5-甲氧基-8-甲基-6-甲酰基-3,4-黄烷二醇, 命名为藤三七醇A(1); 4,7-二羟基-5-甲氧基-8-甲基-6-甲酰基黄烷(2); 7-O-methylunonal(3); 5,7-二羟基-6, 8-二甲基-2-苯基-4H-1-苯并吡喃-4-酮(4); Desmosflavone(5)和Demethoxymatteucinol(6). 其中化合物1是一个新的黄烷二醇化合物, 化合物2~6为首次从该植物中分离得到. 抗HIV-1活性筛选结果表明: 化合物1, 2, 5, 6对HIV-1诱导合胞体的形成具有一定的抑制作用, 其半数有效浓度(EC50)分别为45.09, 48.73, 55.47 和 82.75 μmol/L, 治疗指数(TI)分别为1.41, 1.20, 7.15 和>8.51.     

明日叶黄酮类化合物清除羟基自由基活性研究

为了研究明日叶黄酮类化合物对羟基自由基的清除作用,以明日叶（主要取叶片）为原料,用体积分数为65％乙醇提取明日叶总黄酮,测定其总黄酮含量.通过Fenton反应体系产生羟基自由基,利用明日叶提取液中的功能成分黄酮类化合物对羟基自由基的清除作用进行研究.结果表明：明日叶提取物总黄酮质量分数为10.18％,且黄酮类化合物对羟基自由基有较强清除效力,当提取物总黄酮浓度在0.1～1.0 mg/mL范围内,其与清除率呈正相关.明日叶中黄酮类化合物对羟基自由基有较强清除效力,作为天然抗氧化产品开发具有一定价值.     

超声微波酶解协同提取油茶壳中原花青素

建立了超声微波酶解协同提取油茶壳中原花青素的方法。通过单因素试验,探讨了超声微波协同提取油茶壳中原花青素过程中各主要因素对原花青素提取率的影响规律。实验中发现,往提取液中加入适量纤维素酶,可显著提高原花青素的提取率。在此基础上,通过正交试验,优化并获得了超声微波酶解协同提取原花青素的最适宜条件。最适宜提取条件为:超声波频率40 KHz、微波功率200 W、提取时间60 s、料液比1∶6、提取温度50℃、0.1%纤维素酶0.5 mL、提取次数2次。在最适宜条件下,原花青素的提取率为4.46%,分别是超声提取、微波提取和超声-微波协同提取的4.0、3.3和1.8倍。本文所建立的超声微波酶解协同提取油茶壳中原花青素的方法具有简便、快速、高效和节能等优势,有利于应用推广。     

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.