酶催化反式肉桂酸类似物的不对称氨化反应

在开展应用红酵母PAL酶合成L-苯丙氨酸的基础上,本文首次探讨了该酶不对称氨化反应对部分合成底物的选择性,以拓展它在重要的苯丙氨酸类似物合成方面的应用。     

Direct synthesis of the arylboronic acid analogues of phenylglycine via microwave-assisted four-component Ugi reaction

A four-component Ugi reaction (Ugi-4CR) utilizing formylphenyl boronic acids under mild condition was developed for the synthesis of arylboronic acid analogs. The reactions were performed in methanol and accelerated by microwave irradiation, which makes this strategy suitable for constructing boronic-containing chemical libraries. Two of the synthesized analogs were found to have cytotoxic activity against HepG2, MDA-MB231, and A549 cancer cell lines, demonstrating the potential application of this approach in developing novel boron-containing pharmaceuticals.     

First total synthesis of tenuifolin via PIFA mediated oxidative biaryl coupling

The first total synthesis of a sesquiterpenoid, tenuifolin, was achieved in seven linear steps. Phenyliodine(III) bis(trifluoacetate) (PIFA) mediated oxidative biaryl coupling was employed as a key step to construct the central seven-membered ring with a double bond. The double bond formation was also exploited.     

微波无溶剂法合成香草醛氨基酸席夫碱

氨基酸席夫碱是制备特殊生物活性物质的重要中间体。氨基酸席夫碱中的亚胺(C=N)结构与亚磷酸烷基酯加成的化合物具有良好的抗植物病毒,除草,杀菌等性能[1-3]。氨基酸席夫碱中的羟基,羧基和亚胺等多个活性基团,可以与多种金属离子配位,其配合物具有抗菌,抗病毒,抗癌等性能[4-9],     

Introduction of structural diversity into oligonucleotides containing 6-thioguanine via on-column conjugation

A method is described for the introduction of structural diversity into the thiocarbonyl group of 6-thioguanine within support-bound, fully protected oligonucleotides via ‘on-column′ conjugation. 2′-Deoxy-6-thioguanosine with a chemically-labile trigger at its 6-thio function was incorporated at defined sites into chemically synthesized oligonucleotides. Following selective removal of the thio-protection group the support-immobilized oligonucleotides were conjugated with various groups on-column, and then deprotected and purified to produce a number of oligomers each containing a different modified base. Since the modification is accomplished on-column without affecting other functional and protecting groups in the oligomers this method is compatible with introducing structural diversity at multiple sites in DNA.     

Total synthesis of calothrixins A and B via oxidative radical reaction of cyclohexenone with aminophenanthridinedione

Bioactive indolo[3,2-j]phenanthridine alkaloids, calothrixin B and its N-oxide derivative calothrixin A have been synthesized via an oxidative free radical reaction. Calothrixin B is generated from the commercially available 2,4,5-trimethoxybenzaldehyde in only seven steps. The key step in this synthesis is the Mn(OAc)₃ mediated oxidative free radical reaction of 9-(benzylamino)phenanthridine-7,10-dione with cyclohexenone to form 12-benzyl-12H-indolo[3,2-j]phenanthridine-7,13-dione.     

Facile modifications of a polyimide via chloromethylation. I. Novel synthesis of a new photosensitive polyimide

A soluble aromatic polyimide was chloromethylated via a reaction with chloromethyl methyl ether in the presence of tin(IV) chloride to produce a new starting material for the modification of aromatic polyimides. The chemical structure of the resulting polymer was confirmed by ¹H NMR and Fourier transform infrared spectroscopy. The maximum number of chloromethyl groups per repeat unit was 1.81. The chloromethylated polyimide was stable up to 250 °C and soluble in both chloroform and tetrahydrofuran. So that its utilization for further modification could be demonstrated, cinnamic acid was reacted with the formed polyimide, and it produced a new photosensitive polyimide with a cinnamoyl side chain. The photosensitivity of the resulting polyimide was investigated with ultraviolet spectroscopic methods. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 22–29, 2003     

四种新的水杨醛缩氨基酞菁Schiff碱的合成及光学性质

以四氨基金属酞菁为原料，合成了四种新的Schiff碱C60H36N12O4M(M=Cu，Ni，Zn，Co)，并用质谱、元素分析、红外、紫外对其结构进行了分析和表征．通过荧光光谱对其光学性质进行了研究，四个Schiff碱官能团及中心金属对其光学性质及稳定性有一定的影响．     

噁唑霉素及其类似物的合成研究进展

噁唑霉素及其类似物是由一些链霉菌产生的抗生素,它们都由3个基本骨架单元连接,其独特的生物活性和新颖的化学结构吸引了越来越多的化学与药物化学研究者的关注,从最初发现至今已经有很多研究小组报道了相关的合成研究成果.本文作者基于3个基本组成结构单元,综述了其合成的研究进展,分析了每种合成方法所采用的关键策略,并对该类药物的全合成前景进行了展望.     

Noncovalent synthesis in aqueous solution and spectroscopic characterization of multi-porphyrin complexes

The interactions of the tetracationic meso-tetrakis(N-methyl-4-pyridyl)porphyrin (H(2)TMPyP) and its metallo derivatives (MTMPyP) (where M=copper(II), zinc(II), and gold(III) with the octa-anionic form (at neutral pH) of 5,11,17,23-tetrasulfonato-25,26,27,28-tetrakis(hydroxycarbonylmethoxy)calix[4]arene (C(4)TsTc) lead to a series of complex species whose stoichiometry and porphyrin sequence can be easily tuned. Crystallographic, spectroscopic, and diffusion NMR studies converge towards a common picture in which a central 1:4 porphyrin/calixarene unit serves as a template for the formation of more complex species. These species arise by successive, stepwise addition of single porphyrin molecules above and below the plane of the 1:4 central core to ultimately give a 7:4 complex. Noticeably, the stoichiometry of the various complex species corresponds to the actual concentration ratio of porphyrins and calixarenes in solution allowing the stoichiometry of these species to be easily tuned. This behavior and the remarkable stability of these species allow homo-porphyrin and hetero-(metallo)porphyrin species to be formed with control of not only the stoichiometry but also the sequence of the porphyrin array. The flexibility and ease of this approach permit, in principle, the design and synthesis of porphyrin arrays for predetermined purposes. For example, we have shown that it is very easy to design and obtain mixed porphyrin species in which a foreseen photoinduced electron-transfer is indeed observed.     

Facile synthesis of polymer–peptide conjugates via direct amino acid coupling chemistry

Polymer–peptide conjugates (also known as biohybrids) are attracting considerable attention as injectable materials owing to the self‐assembling behavior of the peptide and the ability to control the material properties using the polymer component. To this end, a simple method for preparing poly(ethylene oxide)‐oligophenylalanine polymer–peptide conjugates (mPEO_m‐F_n‐OEt) using isobutylchloroformate as the activating reagent has been identified and developed. The synthetic approach reported employs an industrially viable route to produce conjugates with high yield and purity. Moreover, the approach allows judicious selection of the precursor building blocks to produce libraries of polymer–peptide conjugates with complete control over the molecular composition. Control over the molecular make‐up of the conjugates allows fine control of the physicochemical properties, which will be exploited in future studies into the prominent self‐assembling behavior of such materials. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 4853–4859     

Short-step synthesis and structure-activity relationship of cortistatin A analogs

An improved method for synthesizing structurally simplified analogs of cortistatin A (1), a novel anti-angiogenic steroidal alkaloid from a marine sponge, was developed. In contrast to previous methods, step- and redox-economical synthesis was achieved using a known α-bromoketone as the starting material. The structure-activity relationship study revealed that the isoquinoline portion was strictly recognized by the target molecule. Surprisingly, the introduction of the acetamide moiety on the A-ring structure dramatically enhanced the selective antiproliferative activity against endothelial cells. This new method can be easily applied to gram-scale synthesis and enabled us to prepare various analogs, which were focused on the participation of the side chain and A-ring structure.     

Efficient synthesis of branched poly(acrylic acid) derivatives via postpolymerization modification

The utility of pentafluorophenyl esters for the selective introduction of functional units and branch points in well-defined poly(acrylic acid) (PAA) derivatives is demonstrated using a combination of controlled radical polymerization and postpolymerization modification. Reversible addition-fragmentation chain transfer enables the synthesis of well-defined copolymers—poly(pentafluorophenyl acrylate-co-tert-butyl acrylate)—with the active ester repeat units serving as attachment points for reaction with primary amines, specifically tris(2-(t-butoxycarbonyl)ethyl)methyl amine (Behera's amine). Deprotection using trifluoroacetic acid removes both the backbone and side chain t-butyl esters to give a series of branched PAA derivatives containing novel tricarboxylic acid side chains that are well suited to complexation and multidentate interactions. Surprisingly, the active ester homopolymer is shown to have the highest reactivity with Behera's amine when compared to copolymers with lower incorporation of pentafluorophenyl esters, suggesting an intriguing interplay of neighboring group effects and steric interactions. The ability to tune the efficiency of postpolymerization modification gives a library of PAA derivatives.     

雷尼替丁的合成及工艺研究

本文对雷尼替丁的传统合成方法进行优化和改进,提高了产物的收率和纯度。氮气保护下,以蒸馏水为溶剂,将N-甲基-1-甲硫基-2-硝基乙烯胺(简称侧三)和2-[[[5-(二甲氨基)甲基-2-呋喃基]甲基]硫基]乙胺(简称氨乙基硫醚)按照摩尔比1.156∶1投料,36℃下反应4h,反应结束后将反应液调酸至p H 3.5~4,经二氯甲烷萃取,有机相回收侧三,回收率高达98.9%;水相调碱至p H 9~10,经萃取、干燥、过滤、浓缩、重结晶,得到雷尼替丁,收率最高达89.7%。     

Microwave-assisted aqueous phase synthesis and single crystal study of oxovanadium(IV) (2-hydroxybenzylideneamino) acetate

Single crystal of oxovanadium(IV) (2-hydroxybenzylideneamino) acetate was synthesized by template method in aqueous phase using microwaves as the source of energy. A fine crystalline complex was obtained in high yield within a few minutes. All bond distances and angles were observed to study the effect of bonding of vanadium and distortion from normal. Other spectroscopic data are also reported.     

Controlled synthesis of oligomeric poly(acrylic acid) and its behavior in aqueous solutions

The controlled synthesis of oligomeric poly(acrylic acid) via the pseudoliving radical reversible addition-fragmentation chain-transfer polymerization of acrylic acid in bulk is developed. It is shown that, at high concentrations of reversible addition-fragmentation chain-transfer agents, the polymerization of acrylic acid in bulk occurs via the pseudoliving mechanism, as evidenced by a linear increase in the numberaverage molecular mass of oligomers with conversion and a narrow molecular-mass distribution of the reaction products. The surfactant properties and behavior of the oligomers in aqueous solutions are studied.     

甾体席夫碱荧光探针的微波合成及其对金属离子的识别

采用石胆酸与2-羟基-1-萘甲醛为原料,合成了一种新型甾体席夫碱结构荧光探针(L),其结构经NMR,IR,ESI-MS和元素分析表征。在pH 7.0缓冲溶液溶液中,探针L可以高选择性荧光识别Al^3+,检测限为8.0 nmol/L,适用范围为pH 6~10。当Al^3+与探针L配位时,生成1:1型配合物(L-Al^3+),在365 nm紫外灯照射下,由无色变成亮蓝色强荧光。