吸电子基对苝酰亚胺微纳米结构传感性能的影响

在苝四酸酐的苝湾(1,7位或1,6,7,12位)位置引入—Cl或—CN,分别制备了两种苝酰亚胺衍生物N,N-双(七氟丁基)-1,6,7,12-四氯-3,4:9,10-苝二酰亚胺(PTCDI-ClF7)和N,N-双(七氟丁基)-1,7-二氰基-3,4:9,10-苝二酰亚胺(PTCDI-CNF7),探索了其在氯仿/甲醇混合溶液中的超分子自组装并测定其微/纳米结构的气敏传感性能。研究显示,两种化合物在苯肼氛围中的灵敏度变化不同,PTCDI-ClF7气敏传感器电阻下降比PTCDI-CNF7高出近2个数量级,其原因是两者占据的最低未占分子轨道(LUMO)能级值相差较大。结果表明:湾位吸电子取代基的不同对苝酰亚胺衍生物微/纳米结构的气敏传感性能影响显著。     

两种新型萘酰亚胺衍生物的合成及表征

以N-己基-4-溴-1,8-萘酰亚胺和1,5-二苯基-3-(2-噻吩)-吡唑啉及1,3-二苯基-5-(2-噻吩)-吡唑啉为原料通过C-H直接芳基化得到两种新型1,8-萘酰亚胺衍生物,N-己基-4-(1,5-二苯基-3-(2-噻吩)吡唑啉)-1,8-萘酰亚胺和N-己基-4-(1,3-二苯基-5-(2-噻吩)吡唑啉)-1,8-萘酰亚胺,探讨了合成机理,并以1H NMR,13C NMR和质谱表征了产物结构。     

基于蒽酰亚胺基团的新型Fe~(3+)和Hg~(2+)化学敏感器

含蒽酰亚胺基团的化合物N-(2-(6-氨基吡啶))-9-蒽酰亚胺(L1)对Fe3+表现出灵敏的荧光增强响应.L1的衍生物N,N-′(2,6-吡啶基)-二(9-蒽酰亚胺)(L2)对Hg2+在紫外-可见吸收光谱和荧光光谱上显示了良好的识别性.即使在其它金属阳离子存在下,L1和L2分别对于Fe3+和Hg2+仍然表现出较好的选择性.     

糖精N-烃化反应的相转移催化

前文报道了聚乙二醇(PEG)在邻苯二甲酰亚胺N-烃化反应中的相转移催化效果,发现PEG的催化效果较为显著并优于季铵盐类催化剂三乙基苄基氯化铵。糖精N-烃基衍生物的经典合成方法和用途早已有文献报道。近来,Perez等用四丁基澳化铵(TBAB)作相转移催化剂合成了糖精N-烃基衍生物。为     

合成N—甲基—4—氨基邻苯二甲酰亚胺的新路线

N-甲基-4-氨基邻苯二甲酰亚胺是合成异鲁米诺衍生物的重要中间体。用它与N-溴烷基邻苯二甲酰亚胺缩合,再经烷基化、肼解,可得到一系列用于发光标记的异鲁米诺衍生物。文献报道,N-甲基-4-氨基邻苯二甲酰亚胺是以4-硝基邻苯二甲酸为原料,经脱水成酐、胺解、还原制得。由于方法所使用的4-硝基邻苯二甲酸较难获得,我们设计了一条合成N-甲基-4-氨基邻苯二甲酰亚胺的新路线:     

1,8-萘酰亚胺分散染料的合成及性能研究

一前言 1,8-萘酰亚胺及其衍生物作为分散染料、有机颜料母体,色泽鲜艳,荧光强烈,可获得优良品种。这类化合物大多具有聚光性,可涉及功能性光导材料。早在三十年代,人们就开始了1,8-萘酐衍生物的研究,早期具有工业价值的有C.I.分散黄11,即N-(2,4-二甲基)-苯基-4-氨基-1,8-萘酰亚胺,在涤纶上染色时色光鲜艳,但上色率较低,耐升华牢度不很     

N-(取代苯基)马来海松酸酰亚胺的合成及表征

松香树脂酸衍生物具有广泛的生物活性。该文以松香为原料,在催化剂对甲基苯磺酸作用下与马来酸酐经Diels-Alder反应制得马来海松酸;马来海松酸与取代苯胺采用一步法在N,N-二甲基甲酰胺(DMF)溶剂中,于155℃反应4 h,合成了8个具有潜在生物活性的N-(取代苯基)马来海松酸酰亚胺化合物,产率为42.5%~84.8%;对产物结构进行了IR、1HNMR、13CNMR光谱表征确认。     

N-(末端三甲基硅酰胺基杂酰胺醚链)邻苯二甲酰亚胺的合成

合成了2个新的N-(末端三甲基硅氮杂酰胺杂醚链)邻苯二甲酰亚胺衍生物化合物。其结构经核磁共振谱、质谱验证。     

脂环类降冰片烯酰亚胺的合成及表征

合成了4种脂环类降冰片烯酰亚胺单体:N-环丙基基降冰片烯酰亚胺(CPrNDI)、N-环戊基降冰片烯酰亚胺(CPenN-DI)、N-环己基降冰片烯酰亚胺(CHexNDI)、N-环庚基降冰片烯酰亚胺(CHepNDI),并通过红外、核磁共振谱(氢谱、碳谱)对所合成的单体进行了表征。     

ZnS:Mn纳米晶的制备及其与羊抗兔抗体偶联的研究

利用金属有机相法合成了高质量的Zn S:Mn纳米晶,经过配体交换,成功将纳米晶溶于PBS缓冲液中。进一步利用1-(3-二甲氨基丙基)-3-乙基碳二亚胺盐酸盐(EDC)和N-羟基硫代琥珀酰亚胺(NHS)使纳米晶表面的羧基活化,与羊抗兔抗体中的氨基形成酰胺键,成功将纳米晶与抗体偶联,最终的偶联产物保持了较高的荧光性能并具有低细胞毒性,满足高质量荧光生物探针的要求。     

巯基化叶酸的制备和表征

通过对基团的保护和脱保护以及酯化反应,合成了目标产物叶酸的衍生物。首先,用三苯甲基对巯基乙醇的巯基进行保护,保护后的巯基乙醇在催化剂作用下与叶酸发生酯化反应,酯化产物在三氟乙酸(TFA)和三乙基硅烷(TES)作用下脱去三苯甲基。通过红外光谱、紫外可见光谱、元素分析、荧光分光光度计和核磁对产物进行表征。结果表明,巯基成功被保护和脱保护,保护后的巯基乙醇与叶酸的羧基发生了反应,叶酸衍生物具有荧光性能,且在靶向肿瘤诊断治疗方面具有潜在的应用价值。     

Polymer-Lipid Matrices based on Carboxymethyl Cellulose/Solagum and Liposomes for Controlled Release of Folic Acid

Liposome-encapsulated folic acid is incorporated into the films made from sodium carboxymethyl cellulose (CMC) (2 mas%) and a mixture of CMC and solagum (9:1 w/w) using the film-forming cast solution method. Histidine is used to increase solubility for folic acid in liposomes (1–5 mg mL⁻¹), and propylene glycol is used as a film plasticizer (2.6 mas%). The obtained films (50–60 µm tick) containing 3.12–20.19 mg of folic acid per gram of film are envisaged to be used as patches for transdermal delivery of folic acid. Therefore, some physical, mechanical, release and structural attributes of the films are scrutinized. Folic acid gives yellow color to the films and contributes to stronger chemical bonds which result in improved strength of the film. Liposomes prolong the release of folic acid from films to 24 h without adverse effects on mechanical properties of the films, but degrade homogeneity of the films, which can be ascribed to its agglomeration within the film matrix as revealed by atomic force microscopy. According to the release at pH 5.5, the film formulation based on a blend of CMC and solagum containing 3 mg mL⁻¹ liposome-encapsulated folic acid is recommended. Practical Application: Folic acid is effective in reducing oxidative stress levels in the skin and neutralizing the harmful free radicals and is also essential for various metabolic reactions in the body. However, the limited solubility of folic acid linked with its poor absorption in an organism, low storage stability, short half-life upon oral consumption, specific food preferences of some people, extensive liver metabolism, and pregnancy-induced vomiting point to a large potential in transdermal usage of folic acid. This has motivated us to design new multicomponent polymer-lipid systems as an alternative solution to overcome some of these drawbacks. The results obtained for these multicomponent films pointed to their potential for prolonged release of folic acid to 24 h, which can also be useful for scientists interested in encapsulating similar poorly soluble compounds in CMC patches. The finding can be also valuable information for pharmaceutical manufacturers and scientists worldwide.     

Short-term folic acid supplementation induces variable and paradoxical changes in plasma homocyst(e)ine concentrations

Folic acid is presently the mainstay of treatment for most subjects with elevated plasma homocyst(e)ine concentrations [Plasma or serum homocyst(e)ine, or total homocysteine, refers to the sum of the sulfhydryl amino acid homocysteine and the homocysteinyl moieties of the disulfides homocystine and homocystein-cysteine, whether free or bound to plasma proteins.] Changes in homocyst(e)ine in response to folic acid supplementation are characterized by considerable interindividual variation. The purpose of this study was to identify factors that contribute to heterogeneity in short-term responses to folic acid supplementation. The effects of folic acid supplementation (1 or 2 mg per day) for 3 wk on plasma homocyst(e)ine concentrations were assessed in 304 men and women. Overall, folic acid supplementation increased mean plasma folate 31.5±98.0 nmol/L and decreased mean plasma homocyst(e)ine concentrations 1.2±2.4 μmol/L. There was evidence of substantial interindividual variation in the homocyst(e)ine response from ?18.5 to +7.1 μmol/L, including an increase in homocyst(e)ine in 20% of subjects (mean increase 1.5±1.4 μmol/L). Basal homocyst(e)ine, age, male gender, cigarette smoking, use of multivitamins, methylene tetrahydrofolate reductase, and cystathionine β-synthase polymorphisms accounted for 47.6% of the interindividual variability in the change in homocyst(e)ine after folic acid supplementation, but about 50% of variability in response to folic acid was not explained by the variables we studied.     

Effect of homocysteine,folates, and cobalamin on endothelial cell- and copper-induced LDL oxidation

Oxidation of LDL contributes to endothelial dysfunction and atherosclerosis. This process could be associated with hyperhomocysteinemia, a condition that can be reduced after folic acid treatment. Because a reduction in LDL oxidation may improve endothelial function, we studied the effect of some vitamins (folic acid, 5-methyltetrahydrofolic acid, and vitamin B-12) on LDL oxidation, either in the presence or absence of homocysteine. For this purpose, two in vitro systems were used: an endothelial cell-catalyzed LDL oxidation system and a cell-free copper-initiated LDL oxidation system. The kinetics of coppercatalyzed LDL oxidation was determined by continuous monitoring of the production of conjugated dienes in the reaction medium. TBARS production, a parameter of lipid peroxidation, was also evaluated. In both in vitro systems, only 5-methyl-tetrahydrofolic acid was able to decrease TBARS production in a concentration-dependent manner, independently of the presence or absence of homocysteine. In the copper-induced LDL oxidation system, vitamin B-12 and 5-methyltetrahydrofolic acid increased the lag time of conjugated diene production by 25 and 47%, respectively, suggesting that both vitamins in this system had antioxidant properties. Folic acid was unable to show antioxidant properties when included in either in vitro system. The results demonstrate that 5-methyltetrahydrofolic acid and vitamin B-12 are important protective agents against LDL oxidative modifications.     

利用山梨酸合成香料叶醇

叶醇及酯是重要而名贵的香料 ,可由山梨酸为原料通过化学合成的方法得到。山梨酸在无水乙醚溶液中用 Li Al H4作还原剂在 2 6～ 30°C下反应 1 .5 h,然后在 Mo( CO) 6的存在下在高压反应釜中进行选择性氢化反应 ,在温度 1 2 0～ 1 40°C下反应 5～ 6h即得产品     

Folate and folic acid intake estimation and food enrichment requirements

The term "folate" is a generic way to name the different forms derived from folic acid, one of the B vitamins (specifically B9 vitamin). They are essential in the metabolism when they act as cofactors in the transfer reactions of one carbon. However, only plants and microorganisms are able to synthesize them de novo, in such a way that both animals and human beings have to intake them through their diet. Folic acid is widely spread in nature, mainly in vegetables, liver ans cereals. However, nowadays, the lack of folates in the diet is one of the most common nutritional deficiencies in the world, and it has serious consequences on human health. There is evidence that even in developed countries folate intake is usually low; and even, is some cases, below optima levels. The authorities in several countries have adapted different norms related to folic acid, fortifying staple food such as dairy products or cereals, mandatory (U.S.A., Canada or Chile) or voluntary (most of the European countries).     

Reactive Oxygen Species and Folate Receptor-Targeted Nanophotosensitizers Composed of Folic Acid-Conjugated and Poly(ethylene glycol)-Chlorin e6 Tetramer Having Diselenide Linkages for Targeted Photodynamic Treatment of Cancer Cells

Folic acid-conjugated nanophotosensitizers composed of folic acid (FA), poly(ethylene glycol) (PEG) and chlorin e6 (Ce6) tetramer were synthesized using diselenide linkages for reactive oxygen species (ROS)- and folate receptor-specific delivery of photosensitizers. Ce6 was conjugated with 3-[3-(2-carboxyethoxy)-2,2-bis(2-carboxyethoxymethyl)propoxy]propanoic acid (tetra acid, or TA) to make Ce6 tetramer via selenocystamine linkages (TA-sese-Ce6 conjugates). In the carboxylic acid end group of the TA-sese-Ce6 conjugates, FA-PEG was attached again using selenocystamine linkages to make FA-PEG/TA-sese-Ce6 conjugates (abbreviated as FAPEGtaCe6 conjugates). Nanophotosensitizers were fabricated by a dialysis procedure. In the morphological observations, they showed spherical shapes with small diameters of less than 200 nm. Stability of the aqueous FAPEGtaCe6 nanophotosensitizer solution was maintained (i.e., their particle sizes were not significantly changed until 7 days later). When H₂O₂ was added to the nanophotosensitizer solution, the particle size distribution was changed from a monomodal pattern to a multimodal pattern. In addition, the fluorescence intensity and Ce6 release rate from the nanophotosensitizers were also increased by the addition of H₂O₂. These results indicated that the nanophotosensitizers had ROS-sensitive properties. In an in vitro cell culture study, an FAPEGtaCe6 nanophotosensitizer treatment against cancer cells increased the Ce6 uptake ratio, ROS generation and light-irradiated cytotoxicity (phototoxicity) compared with Ce6 alone against various cancer cells. When the folic acid was pretreated to block the folate receptors of the Y79 cells and KB cells (folate receptor-overexpressing cells), the intracellular Ce6 uptake, ROS generation and thereby phototoxicity were decreased, while the MCF-7 cells did not significantly respond to blocking of the folate receptors. These results indicated that they could be delivered by a folate receptor-mediated pathway. Furthermore, an in vivo pulmonary metastasis model using Y79 cells showed folate receptor-specific delivery of FAPEGtaCe6 nanophotosensitizers. When folic acid was pre-administered, the fluorescence intensity of the lungs was significantly decreased, indicating that the FAPEGtaCe6 nanophotosensitizers had folate receptor specificity in vitro and in vivo. We suggest that FAPEGtaCe6 nanophotosensitizers are promising candidates for a targeted photodynamic therapy (PDT) approach against cancer cells.     

Voltammetric behavior study of folic acid at phosphomolybdic-polypyrrole film modified electrode

The electrochemical behavior of folic acid at the Keggin-type phosphomolybdate (PMo₁₂) doped polypyrrole (PPy) film modified glassy carbon electrode (PMo₁₂-PPy/GCE) was studied. PMo₁₂ doped PPy modified electrodes were achieved during the electrochemical preparation of the polymer films in aqueous solution. The redox behavior of the modified electrode was described by cyclic voltammetry. The electrochemical behavior of folic acid at PMo₁₂-PPy/GCE was studied by 0.5 order differential voltammetry. Numerous factors affecting the reduction peak currents of folic acid at PMo₁₂-PPy/GCE were optimized to maximize the sensitivity. The results showed that folic acid had high inhibitory activity toward the reduction of modified electrode in 0.01 M H₂SO₄. The reduction peak currents were directly proportional to the concentration of folic acid from 1.0 × 10⁻⁸ to 1 × 10⁻⁷ M with correlation coefficient of 0.9976, a detection limit of 1.0 × 10⁻¹⁰ M of folic acid was estimated. From the inhibitory effect of folic acid on PMo₁₂-PPy/GCE, the apparent formation constant of folic acid with the modified film was estimated. This modified electrode showed excellent sensitivity and stability for the determination of folic acid. The response mechanism of folic acid at PMo₁₂-PPy/GCE was discussed in detail.     

Synthesis and in vitro biological evaluation as antitumour drug carriers of folate‐targeted N‐isopropylacrylamide‐based nanohydrogels

Copolymeric nanohydrogels based on N‐isopropylacrylamide, N‐(pyridin‐4‐ylmethyl)acrylamide and tert‐butyl‐2‐acrylamidoethyl carbamate, synthesized by microemulsion polymerization, were characterized using Fourier transform infrared spectroscopy and their size (38–52 nm) determined using quasielastic light scattering. Folic acid was covalently attached to the nanohydrogels (1.40 ± 0.07 mmol g^?1). Tamoxifen (6.7 ± 0.2–7.3 ± 1.2 µg TMX mg^?1 nanohydrogel), a hydrophobic anticancer drug, and 5‐fluorouracil (7.7 ± 0.7–10.14 ± 1.75 µg 5‐FU mg^?1 nanohydrogel), a hydrophilic anticancer drug, were loaded into the nanohydrogels. Maximum in vitro TMX release (77–84% of loaded drug) depended on interactions of the drug with hydrophobic clusters of the nanogels; however, no nanogel/5‐FU interactions allowed total release of the loaded drug. The cytotoxicity of unloaded nanohydrogels in MCF7, T47D and HeLa cells was low. Cell uptake of nanogels without bound folic acid took place in the three cell types by unspecific internalization in a time‐dependent process. Cell uptake increased for folic acid‐targeted nanohydrogels in T47D and HeLa cells, which have folate receptors. The administration of 10 and 30 µmol L^?1 TMX by TMX‐loaded nanogels and 10 µmol L^?1 5‐FU by 5‐FU‐loaded nanogels was effective on the three cell types, and the best results were obtained for folic acid‐targeted nanohydrogels. Copyright © 2012 Society of Chemical Industry