Synthesis of fluorinated glutamic acid derivatives via vinylalumination

A variety of structural types of fluorinated allylic acetates, prepared by vinylalumination of fluorinated aldehydes, were reacted with the benzophenone imine of glycine tert-butyl ester to provide 4-(fluorobenzylidenyl)- and 4-(fluoroalkylidenyl) glutamic acid derivatives in 61-96% yield. The 4-(4-fluorobenzylidenyl) glutamic acid derivative was hydrolyzed to give the 4-(4-fluorobenzylidenyl)pyroglutamate and then hydrogenated to the 4-(4-fluorobenzyl)pyroglutamate. The catalytic enantioselective conjugate addition-elimination of the benzophenone imine of glycine tert-butyl ester with the fluorinated allylic acetates prepared from fluoral, pentafluorobenzaldehyde, and 2,6-difluorobenzaldehyde provided the corresponding 4-(fluoroalkylidenyl)- and 4-(fluorobenzylidenyl) glutamic acid derivatives in 42, 45 and 80% ee, respectively.     

新型γ-聚谷氨酸吸水树脂的合成

以γ-聚谷氨酸(γ-PGA)为原料,乙二醇缩水甘油醚为交联剂,采用溶液聚合法合成了新型γ-PGA吸水树脂(1),其结构经IR表征.研究了反应体系的pH,反应温度和反应时间对1吸水率和透光率的影响.结果表明,在反应体系pH 4.3,于70℃反应36 h的最佳反应条件下合成1,吸水率220 g·g-1,透光率99.6％,分解温度334.9℃.     

Synthesis of the dibenzyl ester of tert-butoxycarbonyl-L-alanyl-D-glutamic acid from racemic glutamic acid

M. V. Frunze Simferopol' State University. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 865–866, November–December, 1991.     

Electron transfer in electroactive poly(glutamic acid)

Electroactive biopolymer was synthesized by incorporation of ferrocene moieties onto poly(glutamic acid) polymer chains. In the presence of the electron acceptor methyl viologen dichloride, the ferrocene-containing poly(glutamic acid) exhibits efficient photoinduced electron transfer. This redox-active polymer’s electrocatalytic activity for the decomposition of hydrogen peroxide and ascorbic acid was investigated by using cyclic voltammetry. As for hydrogen peroxide, the reduction peak current shows proportional response to peroxide concentration in the wide range of 10-100 mM; as for ascorbic acid, the oxidation peak current displays linear dependence on the ascorbic acid concentration under 80 mM, which could lead to the electroactive biopolymer’s applications in catalysis, photosensitizer, sensors, etc. The study could offer a strategy for developing environment-friendly electroactive and photoactive biopolymers.     

Conductive polymer brushes of regioregular head-to-tail poly(3-alkylthiophenes) via catalyst-transfer surface-initiated polycondensation

We describe a new method to grow conductive polymer (CP) brushes of regioregular head-to-tail poly(3-alkylthiophenes) (P3AT) via surface-initiated polycondensation of 2-bromo-5-chloromagnesio-3-alkylthiophene. A simple procedure for the preparation of the Ni(II) macroinitiator by the reaction of Ni(PPh3)4 with photocross-linked poly-4-bromostyrene films was developed. Exposure of the initiator layers to the monomer solution leads to selective chain growth polycondensation of the monomer from the surface, resulting in P3AT brushes in a very economical way. In contrast to the P3AT films prepared by traditional solvent casting methods, our approach leads to mechanically robust CP films, stable against delamination. We believe that our approach will be helpful in the fabrication of all-plastic devices.     

聚甲基丙烯酸基纳米水凝胶的“绿色”合成

利用原位生成的聚甲基丙烯酸甲酯种子乳胶模板以及表面活性剂与功能单体间的正负电荷作用,发展了一种可在全水相中“绿色”合成聚甲基丙烯酸(PMAA)基纳米水凝胶的新方法.利用动态光散射法、ξ-电位测定、FTIR和TEM对纳米水凝胶的尺寸及其分布、表面电荷、组成、形态、结构和pH响应行为进行了表征.结果表明,PMAA基纳米水凝胶具有聚甲基丙烯酸甲酯内核和交联聚甲基丙烯酸外壳的核壳结构.当甲基丙烯酸(MAA)的用量由2 mL增至3 mL时,PMAA基纳米水凝胶的尺寸变大.当MAA的用量增加至5 mL时,反应体系中除了生成PMAA基纳米水凝胶外,还生成了PMAA次级粒子.PMAA基纳米水凝胶表现出良好的pH响应性:当介质的pH值由2增加至7时,其流体力学体积扩张了近80倍.     

Synthesis of [13C6]3,4-diaminobenzoic acid as a precursor for stable isotope labeled benzimidazoles

The synthesis of [¹³C₆]3,4-diaminobenzoic acid from commercially available [¹³C₆]aniline is described in six steps. Salient features of this route include the preparation of a differentially protected 3,4-diaminobenzonitrile, hydrogen gas free aromatic nitro group reduction with ammonium formate and facile benzimidazole ring closure of the ortho-arylenediamine with triethylorthoformate. This stable-labeled 3,4-diaminobenzoic acid is an ideal [M+6]isotopomer to synthesize complex benzimidazole fragments for mass spectrometry internal assays.     

Synthesis of Poly(glutamic acid-co-aspartic acid) via Combination of N-carboxyanhydride Ring Opening Polymerization with Debenzylation简

The random copolymers of glutamic acid （LG） and aspartic acid （ASP）, poly（LG-co-ASP）, with designed compositions could be successfully synthesized via combination of N-carboxyanhydride ring opening copolymerization with debenzylation. Ring opening copolymerizations of y：benzyl-L-glutamate N-carboxyanhydride （BLG-NCA） and β-benzyl-Laspartate N-carboxyanhydride （BLA-NCA） were carried out by using different amines including triethylamine （TEA）, diethylamine, n-hexylamine （NHA）, triphenylamine, diphenylamine or aniline as initiators. All the 6 amines were highly efficient to get well-defined poly（BLG-co-BLA） copolymers with designed compositions although the polymerizations proceeded via different mechanisms （normal amine mechanism or/and activated monomer mechanism）, which are based on chemical structure of amines. The molecular weights of poly（BLG-co-BLA） copolymers could be mediated by both TEA concentration and polymerization time. Then, debenzylation ofpoly（BLG-co-BLA） copolymers was conducted to prepare the corresponding hydrophilic random eopolymers of poly（LG-co-ASP） with a-subunit structure in ASP structural units. The contents of LG structural units in poly（LG-co-ASP） copolymers matched with those of BLG-NCA in NCA-monomer feeds in ring opening copolymerizations initiated by NHA or TEA and were closed to the theoretical line. The diblock copolymer of poly（BLG-b-BLA） could also be synthesized via living NCA ring opening copolymerization by sequential addition of BLG- NCA and BLA-NCA.     

Synthesis of new fluorescently labeled glycosylphosphatidylinositol (GPI) anchors

The borondipyrromethene (BODIPY) labeled new glycosylphosphatidylinositol (GPI) molecules were synthesized as cellular probes to study the chemical basis of microdomain organization of GPI-anchored proteins and cholesterol in plasma membrane. The synthesis enabled by a new stereo-selective glycosylation of myo-d-inositol acceptor led to the preparation of optically pure glucosaminyl-(1-6)-α-phosphatidyl-myo-d-inositol and its unnatural stereoisomer.     

基于聚谷氨酸囊泡的抗菌水凝胶

通过开环聚合(ROP)合成了两亲嵌段共聚物聚己内酯-聚谷氨酸(PCL-b-PGA),并将其自组装成囊泡,然后利用聚谷氨酸的羧基原位沉积纳米银颗粒,得到了抗菌囊泡. 最后,将抗菌囊泡与普朗尼克F127基体混合,制备了抗菌水凝胶. 实验结果表明抗菌囊泡对典型革兰氏阴性菌如大肠杆菌和典型革兰氏阳性菌如金黄色葡萄球菌的MIC90(抑制90%菌株生长的最低浓度)分别为10和20 μg mL?1. 平板菌落计数法表明抗菌水凝胶对大肠杆菌和金黄色葡萄球菌的MIC50(抑制50%菌株生长的最低浓度)为30 μg mL?1,MIC90为60 μg mL?1. 外敷法抗菌实验也证明了水凝胶具有优异的抗菌效果,其对大肠杆菌和金黄色葡萄球菌的MIC50为7.5 μg mL?1,MBC(最小杀菌浓度)为30 μg mL?1.     

Hyperbranched poly(L-lysine) modified with histidine residues via lysine terminal amino groups: Synthesis and structure

A method for preparing hyperbranched poly(L-lysine) via the polymerization of N^?-carbobenzoxy-L-lysine-N-carboxyanhydride has been developed in order to regulate the molecular mass and size of this polymer and to modify amino groups of its N-terminal lysine residues. This method includes the reductive removal of an N^?-carbobenzoxy group by hydrogen over activated palladium in the presence of a chain termination agent, which is the activated ether of N^α-tert-butyloxycarbonylhistidine. The structure of the polymers has been studied by capillary electrophoresis, circular dichroism, and molecular hydrodynamics.     

Ionic complexes of biosynthetic poly(malic acid) and poly(glutamic acid) as prospective drug-delivery systems

The hydrolytic degradability and erythromycin release from stoichiometric ionic complexes of biotechnological poly(beta,L-malic acid)s and poly(gamma,D-glutamic acid)s with alkyltrimethylammonium surfactants were investigated. The influence of pH, temperature and antibiotic load on hydrolysis rate was examined. It was found that poly(malic acid) complexes degraded by a surface erosion mechanism at a higher rate than poly(glutamic acid) complexes, which eroded in bulk. Erythromycin was lodged in the paraffinic subphase of the complexes and upon aging it was delivered according to a sigmoidal profile that appeared to be independent on the antibiotic load.     

Synthesis of novel gelatin/poly(acrylic acid) nanorods via the self-assembly of nanospheres

In this work,gelatin-poly(acrylic acid) (GEL-PAA) nanospheres with diameter of around 35 nm were prepared using a polymermonomer (gelatin-AA) pair reaction system.These nanospheres can self-assemble into nanorods in aqueous solution at 4 °C.Based on the observation that the intermediate state of the formation of the nanorods and the facts that the self-assembly can only occur at relatively low temperature and the gelatin molecules on the outermost layer of the GEL-PAA nanospheres can be renatured to triple ...     

Synthesis of pyrimidin-2-ylaminophosphonic di(ethyleneamide) (fosfemid) labeled at the phosphorus atom

Pyrimidin-2-ylaminophosphonic di(ethyleneamide) labeled at the phosphorus atom (fosfemid-³²P) has been synthesized both in an anhydrous medium and also using an aqueous alkaline solution of ethyleneimine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1251–1253, September, 1973.     

明胶-聚丙烯酸纳米微球的一维自组装制备纳米棒

明胶-聚丙烯酸纳米微球可在4℃下自组装形成纳米棒,所形成的纳米棒结构规整并具有与纳米微球相同的直径.通过观察纳米棒形成的中间状态,发现该纳米棒由明胶-聚丙烯酸纳米微球一维排列而成.由于只有在较低温度下纳米微球才能形成棒状结构,并且圆二色性光谱数据证明明胶-聚丙烯酸纳米微球表面的明胶分子具有在低温下复性成为三螺旋构象的能力,因此可以推断明胶-聚丙烯酸纳米棒是由纳米微球表面的明胶分子通过复性为三螺旋结构所产生的氢键以及静电等力的作用一维自组装而形成的.