Toward controlling gene expression at will: Specific regulation of the erbB-2/HER-2 promoter by using polydactyl zinc finger proteins constructed from modular building blocks

To create a universal system for the control of gene expression, we have studied methods for the construction of novel polydactyl zinc finger proteins that recognize extended DNA sequences. Elsewhere we have described the generation of zinc finger domains recognizing sequences of the 5′-GNN-3′ subset of a 64-member zinc finger alphabet. Here we report on the use of these domains as modular building blocks for the construction of polydactyl proteins specifically recognizing 9- or 18-bp sequences. A rapid PCR assembly method was developed that, together with this predefined set of zinc finger domains, provides ready access to 17 million novel proteins that bind the 5′-(GNN)6-3′ family of 18-bp DNA sites. To examine the efficacy of this strategy in gene control, the human erbB-2 gene was chosen as a model. A polydactyl protein specifically recognizing an 18-bp sequence in the 5′-untranslated region of this gene was converted into a transcriptional repressor by fusion with Krüppel-associated box (KRAB), ERD, or SID repressor domains. Transcriptional activators were generated by fusion with the herpes simplex VP16 activation domain or with a tetrameric repeat of VP16’s minimal activation domain, termed VP64. We demonstrate that both gene repression and activation can be achieved by targeting designed proteins to a single site within the transcribed region of a gene. We anticipate that gene-specific transcriptional regulators of the type described here will find diverse applications in gene therapy, functional genomics, and the generation of transgenic organisms.

Supramolecular coordination complexes as building blocks for porous and magnetic materials

In this work, new coordination polymers based on two different classes of synthons are presented. In addition, manganese-based metallacrowns of magnetic interest are studied, both in the solid state and in solution. Firstly, functionalized bispyrazolylmethane derivatives are employed as bridging ligands for the establishment of silver-based coordination polymers; the influence of the substituent groups and of the counterions on the supramolecular packing is also investigated. Secondly, the use of metallacrown (MC) complexes as building blocks for porous coordination polymers is discussed. The design of a new metallacrown species is presented, which shows the tendency of aggregating in the solid state to form coordination polymers. Two new coordination polymers are indeed reported, of which one is the first MC-based permanently porous coordination network ever presented. The solid resists solvent evacuation and exhibits gas uptake ability. Furthermore, the isolation and characterization of a new metallacryptate species based on manganese ions is described. The metal-rich structure comprises nine Mn(II)/Mn(III) ions and presents an inverse metallacrown core subunit that binds a μ3-O2- ion. The metallacryptate is isolated in high yields and stable in solution. Lastly, a family of 3d-4f heterometallic metallacrowns is characterized in solution by means of UV-Vis spectrophotometry and of paramagnetically shifted 1H-NMR. The lanthanide-induced shifts observed in the spectra are employed to describe the molecules behaviour in solution and are qualitatively related to the magnetic properties of the compounds.

Intramolecular Bromoamination of Conjugated N-Tosylaminodienes Using N-Bromosuccinimide. Synthesis of Bromoallyl-Substituted N-Heterocycles and Their Applications as Building Blocks

The bromonium-promoted cyclization of conjugated aminodienes is described. The reaction proceeds smoothly in the presence of N-bromosuccinimide as halonium promoter, and using N-tosyl-protected aminodienes as substrates, to give the corresponding halocyclization products in high yields and with high diastereoselectivities. It can be envisaged that the formation of these products is the result of an SN2′-type ring-opening of a terminal bromonium intermediate in a 5-exo-trig or 6-exo-trig cyclization mode. The presence of an allyl bromide moiety in the haloamination products makes these molecules highly attractive from a synthetic point of view, as it opens the way for further transformations. Thus, allylic substitution reactions with different nucleophiles (acetate, azide, cyanide, and malonate), palladium-catalysed Suzuki coupling, and silver-mediated bromine displacement reactions were carried out successfully.

TMO revisited : an evaluation report : toward a multicultural organization : building blocks to meet 21st century challenges.

"FS-631"--P. [4] of cover.

The sugar cane biofactory - building blocks for the future

The sugarcane plant, with its enormous genetic capacity to accumulate carbon and manufacture and store sucrose, also has the potential to accumulate carbon and metabolically create a wide range of new molecules for industrial and other commercial uses. The extent to which this change can be developed and realised commercially is a function of the technical competence of the industry's R&D capacity, the reality of the commercial drivers which support this global agenda, and the determination of the industry to achieve such goals. The outcomes of existing R&D work already strongly support the technical challenges of this opportunity in sugarcane. The current challenge remains the commercialisation of the technology in a global market in which the current business structures and systems for the manufacture and distribution of existing (competitive) products makes the development of new product lines a higher risk than might otherwise be the case. This is despite all the claims that global markets are expecting and (in some cases) legislating the creation of more sustainable production systems. The options and issues for the development of a sugarcane biofactory system are discussed.

Selective functionalisation of Re6 cluster anionic units:from hexa-hydroxo [Re6Q8(OH)6]4− (Q = S, Se) to neutral trans-[Re6Q8L4L′2] hybrid building blocks

The reaction of [Re6Q8(OH)6]4- (Q = S, Se) with p-tertbutylpyridine (TBP) in water leads to neutral trans-[Re6Q8(TBP)4(OH)2] whose hydroxyl reactivity with carboxylic acid and TBP exchange reaction with functional pyridine have been investigated.

Synthesis and characterization of electron deficient heterocycles as building blocks for electronic materials

This thesis describes the synthesis of a new electropolymerizable viologen derivative. A reasonably high-yielding route is reported, and a preliminary investigation of its polymerisation is described. The viologen and its precursors were examined by 1H NMR, MS, IR and elemental analysis. The energies of the band gap for the materials have been calculated using UV-vis spectroscopy, and cyclic voltammetry was also used to estimate the oxidation and the reduction potentials and to calculate the HOMO and LUMO energies. Theoretical calculations were performed using DFT. The attempted synthesis of a new flavin-functionalised phenanthroline derivative is described. Unfortunately, the protocol used failed to provide the desired compounds.

Palladium-Catalyzed Decarboxylative and Decarbonylative Transformations in the Synthesis of Fine and Commodity Chemicals

Decarboxylation and decarbonylation are important reactions in synthetic organic chemistry, transforming readily available carboxylic acids and their derivatives into various products through loss of carbon dioxide or carbon monoxide. In the past few decades, palladium-catalyzed decarboxylative and decarbonylative reactions experienced tremendous growth due to the excellent catalytic activity of palladium. Development of new reactions in this category for fine and commodity chemical synthesis continues to draw attention from the chemistry community.

The Stoltz laboratory has established a palladium-catalyzed enantioselective decarboxylative allylic alkylation of β-keto esters for the synthesis of α-quaternary ketones since 2005. Recently, we extended this chemistry to lactams due to the ubiquity and importance of nitrogen-containing heterocycles. A wide variety of α-quaternary and tetrasubstituted α-tertiary lactams were obtained in excellent yields and exceptional enantioselectivities using our palladium-catalyzed decarboxylative allylic alkylation chemistry. Enantioenriched α-quaternary carbonyl compounds are versatile building blocks that can be further elaborated to intercept synthetic intermediates en route to many classical natural products. Thus our chemistry enables catalytic asymmetric formal synthesis of these complex molecules.

In addition to fine chemicals, we became interested in commodity chemical synthesis using renewable feedstocks. In collaboration with the Grubbs group, we developed a palladium-catalyzed decarbonylative dehydration reaction that converts abundant and inexpensive fatty acids into value-added linear alpha olefins. The chemistry proceeds under relatively mild conditions, requires very low catalyst loading, tolerates a variety of functional groups, and is easily performed on a large scale. An additional advantage of this chemistry is that it provides access to expensive odd-numbered alpha olefins.

Finally, combining features of both projects, we applied a small-scale decarbonylative dehydration reaction to the synthesis of α-vinyl carbonyl compounds. Direct α-vinylation is challenging, and asymmetric vinylations are rare. Taking advantage of our decarbonylative dehydration chemistry, we were able to transform enantioenriched δ-oxocarboxylic acids into quaternary α-vinyl carbonyl compounds in good yields with complete retention of stereochemistry. Our explorations culminated in the catalytic enantioselective total synthesis of (–)-aspewentin B, a terpenoid natural product featuring a quaternary α-vinyl ketone. Both decarboxylative and decarbonylative chemistries found application in the late stage of the total synthesis.

Photonic nanowires directly drawn from bulk glasses

High-uniform nanowires with diameters down to 50 nm are directly taper-drawn from bulk glasses. Typical loss of these wires goes down to 0.1 dB/mm for single-mode operation. Favorable photonic properties such as high index for tight optical confinement in tellurite glass nanowires and photoluminescence for active devices in doped fluoride and phosphate glass nanowires are observed. Supporting high-index tellurite nanowires with solid substrates (such as silica glass and MgF2 crystal) and assembling low-loss microcoupler with these wires are also demonstrated. Photonic nanowires demonstrated in this work may open up vast opportunities for making versatile building blocks for future micro- and nanoscale photonic circuits and components. (c) 2006 Optical Society of America.

路易斯碱催化还原胺化反应研究

胺及其衍生物是很多重要生物活性分子的结构单元，是合成天然产物和手性药物的重要中间体。 直接还原胺化由于其合成步骤简单而成为制备二级胺和三级胺的简便方法。为了发展一种较为简便的直接还原胺化反应，我们把研究的重点放在开发一种简便实用的有机小分子催化方法上。由文献调研可知，现已报道的直接还原胺化方法大多是催化醛或酮与一级胺或者脂肪二级胺的直接还原胺化，而醛或酮与芳香二级胺的直接还原胺化却尚无报道。在本文中，我们发现用简单的四甲基乙二胺(TEMED)在室温下以二氯甲烷为溶剂即可催化三氯氢硅对酮和芳香二级胺之间的直接还原胺化反应，并取得了高达92%的收率。该反应条件温和，底物普适性广，各种类型的酮均可以与芳香二级胺进行直接还原胺化，并且得到比较满意的收率。 同时，我们从手性Sulfoximine出发，设计和合成了一系列的Sulfoximine类新衍生物，并将其应用于间接还原胺化反应中。遗憾的是我们并没有得到预期的不对称催化效果。 Amines and their derivatives are basic structural motifs in natural products and pharmaceuticals and highly versatile building blocks for various organic substrates. Direct reductive amination (DRA) is a convenient method for the preparation of secondary and tertiary amines owing to its operational simplicity. In an effort to develop a simple and convenient procedure for direct reductive amination reaction, we focused our study on search for a mild and efficient organocatalytic system. In the literature, there are many reports concerning DRA between aldehydes or ketones and either primary amines or secondary aliphatic amines. But there are no reports concerning DRA between aldehydes or ketones and secondary aromatic amines. In this study, we have developed a highly practical method for the synthesis of tertiary amines by the direct reductive amination of ketones and secondary aromatic amines with tetramethylethylenediamine (TEMED) as the catalyst using HSiCl3 as the reducing agent in dichloromethane (affording up to 92% yield). This method can be carried out under mild conditions and is compatible with many functional groups. A variety of ketones were efficiently aminated with secondary aromatic amines to afford the corresponding amines in good to excellent yields. Starting from chiral sulfoximine, we designed and synthesized a series of new sulfoximine derivatives and tested their efficiencies as asymmetric organocatalysts for the reduction of imines, which, unfortunately, only exhibited low catalytic activity and enantioselectivity.

Oligoaniline-Functionalized terpyridine ligands and their ruthenium(II) complexes: synthesis, spectroscopic property and redox behaviors

A series of oligoaniline-functionalized mono- and bis-topic terpyridine ligands, i.e. C6H5[N(R)C6H4](n)TPY (R = H, butyl, tert-butyloxycarbonyl; n = 1-4; TPY = 2,2':6',2"-terpyridyl) and TPYC6H4[N(R)C6H4](m)TPY (R = H, tert-butyloxycarbonyl; m = 2, 4), and the corresponding monoand bis-nuclear ruthenium(II) complexes have been synthesized and verified. The spectroscopic results indicate that two kinds of pi-pi* transitions from TPY and oligoaniline fragments of ligands strongly shift to lower energy, and the metal-to-ligand charge-transfer transition ((MLCT)-M-1) bands of all obtained complexes are considerably red-shifted (Delta lambda(max) = 22-64 nm) and their intensities become much more intense (approximately 4-6 times), compared with those of the reported complex [Ru(TPY)(2)](2+). Moreover, the spectroscopic properties of the ligands and complexes with longer oligoaniline units (n = 3, 4) are markedly influenced by the external stimulus, such as the oxidation and proton acid doping.

Síntesi en dissolució i fase sòlida de nous derivats primidínics amb una alta diversitat molecular

En aquest treball s'ha desenvolupat una metodologia eficaç envers la síntesi de diferents derivats pirimidínics amb un alt grau de diversitat molecular. Aquesta metodologia es basa en la S-alquilació selectiva dels 2-tiouracils (2) utilitzats com a material de partida. Aquesta reacció es realitza amb bromur de benzil quan es treballa en dissolució, o bé amb la reïna de Merrifield quan la química és sobre suport sòlid. Seguidament, s'alquila selectivament l'àtom d'oxigen de les benzilsulfanilpirimidinones (3) mitjançant la reacció de Mitsunobu, o bé utilitzant diferents halurs d'alquil en presència d'una base. Amb les 4-alcoxipirimidines (4) es realitzen diverses transformacions químiques, per exemple, addicions de Grignard, reducció i posterior metilació del grup carbonil (quan R2 = CH2COPh), etc. Posteriorment, s'oxida el grup sulfanil a sulfona utilitzant m-CPBA. Finalment es desplaça la funció sulfona amb diversos nucleòfils. Gràcies a aquesta metodologia s'han preparat diferents 2-amino-4-alcoxipirimidines (7, Nu = RR'N) en dissolució i sobre suport sòlid. Mitjançant algunes variacions s'han pogut obtenir altres derivats pirimidínics: - 4(3H)-pirimidinones 2,6-disubstituïdes (8, Nu = RR'N, ArO, RR'R''C), preparades a partir de la hidròlisi del grup alcòxid (OR5) dels compostos (7) en medi àcid. - imidazo[1,2-a]pirimidinones (9 o 10, n = 1) i pirimido[1,2-a]pirimidinones (9 o 10, n = 2). Els compostos (9) s'han obtingut selectivament a través d'una ciclació intramolecular de les pirimidines (7, Nu = aminoalcohols) utilitzant àcid sulfúric. Quan s'han ciclat els compostos (8, Nu = aminoalcohols) mitjançant una reacció de Mitsunobu intramolecular, s'han obtingut els regioisòmers (9) i (10) en diferents proporcions en funció dels grups presents en l'anell. - pirimidines funcionalitzades amb restes d'-arilglina (11). La funció arilglicina s'ha preparat mitjançant la condensació d'amines (4, R2 = CH2CHR3NHR4) amb àcid glioxàlic i àcids arilborònics (reacció de Petasis). L'oxidació del grup sulfanil dels compostos (11) a sulfona utilitzant m-CPBA ha provocat també l'oxidació de l'àtom de nitrogen de l'arilglicina. Alguns d'aquests derivats pirimidínics han mostrat ser inhibidors del Mycobacterium tuberculosis.