银纳米粒子的绿色合成及其对荧光素室温磷光的增强效应

以β-环糊精(β-CD)作为稳定剂, 葡萄糖为还原剂, 银氨溶液为前驱体, 实现了绿色化学方法合成银纳米粒子. 利用紫外-可见分光光度法(UV-Vis)、高分辨透射电镜(HRTEM)、红外光谱法(FTIR)对产物进行了表征. 将银纳米粒子引入滤纸表面增强室温磷光(RTP)的研究, 发现银纳米粒子对醋酸铅诱导荧光素(FL)所得的RTP具有明显的增强效应, 并且随着银纳米粒子加入量的增加具有先增强后猝灭的趋势. 对β-CD与银纳米粒子的相互作用机理及银纳米粒子对FL RTP增强效应的作用机理进行了初步讨论.     

β-榄香烯含S, Se糖苷衍生物的设计合成

以β-榄香烯(1)为先导化合物, 经由其13位氯代物(2), 依据生物电子等排原理将具有相似共价半径的杂原子S和Se分别引入到β-榄香烯的骨架中, 得到一对相应的类似物3和6; 进而通过多种方法与系列糖供体对接, 立体选择性地合成了相应的乙酰化1,2-反式糖苷类衍生物11a~11c和12a~12c, 经水解脱去保护基团, 得到目标产物β-榄香烯含S糖苷13a~13c及其类似物β-榄香烯含Se糖苷14a~14c. 目标化合物的结构经IR, 1H NMR, 13C NMR, 77Se NMR, HRMS等方法确证.     

β-榄香烯聚乙二醇衍生物的合成及体外抗癌活性

以中草药有效成分β-榄香烯为起始原料, 在碱性条件下与氨基化的聚乙二醇(PEG)反应合成了一系列β-榄香烯单取代PEG衍生物, 利用IR, ¹H NMR及¹³C NMR对其结构进行了表征. 并采用WST-1法观察其对人宫颈癌细胞(Hela)、人白血病细胞(K562)的抑制作用, 探讨其体外抗肿瘤活性. 细胞实验结果表明经PEG修饰的β-榄香烯的抗癌活性有不同程度的增强.     

一种4β-氨基鬼臼毒素的合成新方法

报道了一种在室温条件下和在四氢呋喃水溶液中用Zn/HCO2NH4还原4β-叠氮鬼臼毒素制备抗癌药物中间体4β-氨基鬼臼毒素的新方法. 此方法具有产率高(96%)、不需要用贵金属(如钯或钐)催化和无水条件、操作方便等优点. 最佳的反应条件为: 底物、Zn和HCO2NH4的物质的量之比为1∶2∶4, 反应溶剂为85%四氢呋喃水溶液, 反应时间为5 h.     

腈的生物转化不对称合成β-氨基酸和β-氨基酰胺

含有腈水合酶和酰胺水解酶的红球菌Rhodococcus erythropolis AJ270能在非常温和的条件下催化一系列β-氨基苯丙腈衍生物的水解反应, 生成相应的β-氨基酸和β-氨基酰胺. 底物结构对生物转化反应的效率及立体选择性影响很大. 3-氨基-3-苯丙腈的生物水解反应显示了较低的立体选择性, 而氮甲基取代衍生物的水解反应则显示了中等立体选择性, 生成相应S构型β-氨基酸和R构型β-氨基酰胺. 氮上大位阻取代基显著降低生物催化效率.     

Synthesis and Crystal Structure of 3,6-Bis（4,4,4- trifluorobutane- 1,3-dione）-9-n-butylcarbazole

A novel bis（β-diketonate） derivate, 3,6-bis（4,4,4-trifluorobutane-1,3-dione）-9-n- butylcarbazole 1, was synthesized and structurally characterized by single-crystal X-ray diffrac- tion. The crystal belongs to the monoclinic system, space group P2 1/c with a = 10.961（6）, b = 22.942（13）, c = 9.408（6）A, α = 90, β = 109.663（9）, y = 90°, V = 2228（2）A^3, Z = 4, Dc = 1.489 g/cm^3, C24H19F6NO4, Mr = 499.40, F（000） = 1024 and μ = 0.134 mm^-1. The structure was refined to the final R = 0.0699 and wR = 0.1627 for 3744 independent reflections （Rint = 0.1288） and 1349 observed reflections （I 〉 2σ（I））. Compound 1 consists of carbazole unit and two terminal diketonate groups, in which carbazole and its two adjacent diketonate rings are almost coplanar. Moreover, compound 1 was characterized with IR, elemental analysis, IH NMR, MS, electronic absorption, and single-photon fluorescence.     

Use of the Pictet-Spengler reaction for the synthesis of 1,4-disubstituted-1,2,3,4-tetrahydro-β-carbolines and 1,4-disubstituted-β-carbolines: formation of γ-carbolines

Microwave-assisted conjugate addition of indole on nitro-olefins furnished nitro compounds, which were reduced to tryptamines. Further, by using Pictet-Spengler condensation, new 1,4-disubstituted-1,2,3,4-tetrahydro-β-carbolines were synthesized in diastereoselective manner. Dehydrogenation of the tetrahydro-β-carbolines produced new 1,4-disubstituted-β-carbolines. As a new observation, in some of the cases, Pictet-Spengler condensation and dehydrogenation gave two products, namely 1,4-disubstituted-β-carbolines and 1,4-disubstituted-γ-carbolines. A mechanism is proposed for this observation.     

1,2-Acyl group migration in the oxidative free radical reaction of 2-substituted-1,4-quinones

Oxidative free radical reactions of 2-substituted-1,4-quinone derivatives are described. Electrophilic carbon-centered radical produced by the manganese(III) acetate oxidation of α-chloro-β-ketoester undergoes efficient addition to the C-C double bond of 5,6-dimethyl-2-(methylamino)-1,4-benzoquinone, and this reaction provides a novel method for the synthesis of spirolactam 3 and indole-2,4,7-trione 4. It shows high chemoselectivity depending on the migratory aptitude of the substituent on α-chloro-β-ketoester. Imine radical can be generated from the oxidation of β-enamino carbonyl compound with Mn(III) or Ce(IV) salt. With 2-hydroxy-1,4-naphthoquinone, spirolactam 6 was prepared from β-enamino carbonyl compound effectively. TBACN/CHCl₃ is the most effective reaction condition for the formation of 6.     

Aminomethylation of chiral silyl enol ethers: access to β-homotryptophane and β-homolysine derivatives

We describe here the aminomethylation of chiral silyl enol ether derivatives using iminium ion. The choice of judicious precursors with adequate protecting groups for the silylation/aminomethylation step was required to achieve the synthesis of β²-homotryptophane in few steps. The same methodology was used to prepare a β²-homolysine derivative.     

Silica gel accelerated aza-Michael addition of amines to α,β-unsaturated amides

A novel method to synthesize β-amino amide has been developed via conjugated addition of amine to bulky α,β-unsaturated amides promoted by silica gel. The silica gel worked efficiently to accelerate the reaction and afforded the related adduct in good to excellent yield.