- Stereoselective Adsorption on a Gold-Thiol Monolayer with an Enantiopure Surface
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Self-assembled films of (+)-11-toluene-p-sulfinylundecanethiol on gold have been shown to adsorb the enantiomeric ethyl lactates from the gas phase; adsorption is totally unselective when the system is not in equilibrium during short exposures at 20 deg C but becomes totally selective after extended exposure at 40 deg C.
- Davis, Frank,Neogi, Partha,Stirling, Charles J. M.
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Read Online
- ALKYL SULFATE ESTER OR SALT OF SAME
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An alkyl sulfate ester containing a carbonyl group or a salt thereof. The compound is represented by the following formula: R1—C(═O)—(CR22)n—(OR3)p(CR42)q-L-OSO3X wherein R1, R2, R3, R4, L, X, n, p and q are as defined herein. Also disclosed is a production method for making the alkyl sulfate ester.
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Paragraph 0337-0340
(2021/01/22)
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- Synthesis and characterization of some atypical sphingoid bases
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Sphingolipids are ubiquitous and abundant components of all eukaryotic and some prokaryotic organisms. Sphingolipids show a large structural variety not only between the different species, but also within an individual cell. This variety is not limited to alterations in the polar headgroups of e.g. glycosphingolipids, but also affects the lipophilic anchors comprised of different fatty acids on the one hand and different sphingoid bases on the other hand. The structural variations within different sphingoid bases e.g. in pathogens can be used to identify novel biomarkers and drug targets and the specific change in the profile of common and uncommon sphingolipids are associated with pathological conditions like diabetes or cancer. Therefore, the emerging field of sphingolipidomics is dedicated to collect data on the sphingolipidome of a cell and hence to assign changes therein to certain states of a cell or to pathological conditions. This powerful tool however is still limited by the availability of structural information about the individual lipid species as well as by the availability of appropriate internal standards for quantification. Herein we describe the synthesis of a variety of 1-deoxy-sphingoid bases. 1-DeoxySphingolipids have recently acquired significant attention due to its pathological role in the rare inherited neuropathy, HSAN1 but also as predictive biomarkers in diabetes type II. Some of the compounds synthesized and characterized herein, have been used and will be used to elucidate the correct structure of these disease-related lipids and their metabolites.
- Saied, Essa M.,Le, Thuy Linh-Stella,Hornemann,Arenz, Christoph
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supporting information
p. 4047 - 4057
(2018/06/30)
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- Total Synthesis and Structural Elucidation of Two Unusual Non-Methylene-Interrupted Fatty Acids in Ovaries of the Limpet Cellana toreuma
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In our previous study, unusual odd-numbered dienoic acids with a terminal olefin were found as minor components in ovaries of the Japanese limpet Cellana toreuma, and the synthetic interests have been focused onto their structural confirmation and the inspection into their potential biological activity. Here, we describe an efficient and stereoselective total synthesis of two new unusual dienoic acids, 19:2?7,18 and 21:2?7,20, through a common pathway involving the strategic combination of alkyne-zipper reaction and Lindlar hydrogenation for the construction of their unique carbon chains. In our synthetic study, 2-propyn-1-ol was at first subjected to alkylation and alkyne-zipper reaction to form the two fragments, and the subsequent carbon chain elongation was achieved by the usual coupling reaction to obtain the C-19 and C-21 products bearing an internal acetylenic group. Then, the internal acetylenic group of these products was subjected to Lindlar hydrogenation to form a Z-alkenyl moiety, and the subsequent deprotection of the products was carried out under an acidic condition without isomerization of the internal Z-alkenyl group. Total synthesis of target fatty acids, 19:2?7,18 and 21:2?7,20, was finally accomplished by two-step oxidation of the resulting alcohols into carboxylic acids in a highly chemoselective manner, and the structures of these unusual natural fatty acids were finally elucidated by identifying the GC–MS spectra of the methyl esters of authentic and synthetic fatty acids.
- Shimada, Kazuaki,Sugawara, Ayako,Korenaga, Toshinobu,Kawashima, Hideki
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p. 1019 - 1032
(2017/10/07)
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- A magnetic nanoparticle-supported N-heterocyclic carbene-palladacycle: An efficient and recyclable solid molecular catalyst for Suzuki-Miyaura cross-coupling of 9-chloroacridine
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A robust magnetic nanoparticle-supported N-heterocyclic carbene-palladacycle has been readily synthesized by directly anchoring the structural defined acenaphthoimidazolylidene palladacycle with a long tail on magnetic nanoparticles (MNPs), and functioned as a solid molecular catalyst and exhibited extremely high catalytic activity towards the challenging Suzuki-Miyaura cross-coupling reactions between less-studied heterocyclic 9-chloroacridine and diverse boronic acids. Remarkably, the catalyst could be used 5 times without obvious loss of activity highlighting the efficiency of our strategy of immobilization of previledged catalysts.
- Deng, Qinyue,Shen, Yajing,Zhu, Haibo,Tu, Tao
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supporting information
p. 13063 - 13066
(2017/12/15)
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- Microorganism detection and analysis using carbohydrate and lectin recognition
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Methods of binding and detecting a microorganism on a solid substrate. The microorganism is bound on a solid substrate covalently bound to a capture agent having a saccharide moiety. A lectin capable of binding to the microorganism and the saccharide moiety of the capture agent is added to the sample to bind the microorganism on the solid substrate. Further provided are biosensor devices, such as a quartz crystal microbalance (QCM) device or a surface plasmon resonance (SPR) device, that incorporate the solid substrate for the detection of microorganisms.
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Page/Page column 11
(2016/09/26)
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- Synthesis and characterization of precisely-defined ethylene-co-aryl ether polymers via ADMET polymerization
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A new family of polyolefins containing various aryl ether units have been designed and synthesized, and their thermal properties were studied. We prepared six acyclic diene monomers di(undec-10-enyloxy)aryl ether by a two-step approach and the corresponding homopolymers and copolymers with 1,9-decadiene by ADMET. Subsequent hydrogenation gave the corresponding ethylene-co-aryl ether polymers. The structures of these polymers were confirmed by 1H NMR, 13C NMR and FT-IR. Additionally, crystallization behaviors and thermal properties were investigated by differential scanning calorimetry (DSC), X-ray diffraction and thermal gravimetric analysis (TGA). The results show that incorporation of these aryl ether units has improved the thermal stability of polymers. And these polymers show a tendency of semicrystallinity to amorphous state with the insertion of more rigid phenyl rings in functional sites of polymers' main chain. Interestingly, DSC analysis reveals that a sequence of melting/crystallization phenomenon occurs in the crystalline saturated homopolymers.
- Song, Shaofei,Miao, Weijun,Wang, Zongbao,Gong, Dirong,Chen, Zhong-Ren
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- ADMET Polymers Containing Precisely Spaced Pendant Boronic Acids and Esters
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Precise aryl boronic ester- and acid-containing polymers have been synthesized via acyclic diene metathesis. High-molecular weight phenyl boronic acid polymers were synthesized. Cross-linked phenyl boronic acid polymers were also synthesized and demonstrate a unique crystallization behavior not usually seen in cross-linked polymers. (Graph Presented).
- Simocko, Chester,Young, Thomas C.,Wagener, Kenneth B.
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p. 5470 - 5473
(2015/09/02)
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- 3-METHYL-6-CYCLOHEXADECEN-1-ONE AND ITS USE IN PERFUME COMPOSITIONS
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The present invention is directed to a novel compound, 3-methyl-cyclohexadec-6-enone, and a method of improving, enhancing or modifying a fragrance formulation through the addition of an olfactory acceptable amount of 3-methyl-cyclohexadec-6-enone.
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Paragraph 0028-0030
(2013/03/26)
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- Decreasing the alkyl branch frequency in precision polyethylene: Effect of alkyl branch size on nanoscale morphology
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Synthesis and morphological characterization are reported for a series of 13 precision branched polyethylene structures, the branch being placed on every 39th carbon and varying in size from methyl to pentadecyl group. A recently established synthetic scheme for preparation of the symmetrical α,ω-diene monomer was employed to increase the number of methylene carbons between the branch points from 20 to 38, yielding polymers with 5.26 mol % α-olefin incorporation. The morphology of these polymers was investigated using differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), and transmission electron microscopy (TEM). Methyl branching significantly reduces the melting point and single crystal lamellae thickness of unbranched polyethylene. On the other hand, all further branches from ethyl to pentadecyl produce polymers that have similar melting points and single crystal lamellae thicknesses. A clear change in the morphology of both solution and melt-grown crystals of these polymers was observed from a situation where the methyl branch is incorporated in the polymer's unit cell to one where branches of greater mass are mostly expelled from the unit cell.
- Inci, Bora,Lieberwirth, Ingo,Steffen, Werner,Mezger, Markus,Graf, Robert,Landfester, Katharina,Wagener, Kenneth B.
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scheme or table
p. 3367 - 3376
(2012/07/28)
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- Indium-catalyzed reductive bromination of carboxylic acids leading to alkyl bromides
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The combination of 1,1,3,3-tetramethyldisiloxane (TMDS) and trimethylbromosilane (Me3SiBr) with a catalytic amount of indium bromide (InBr3) undertook direct bromination of carboxylic acids, which produced the corresponding alkyl bromides in good to excellent yields. The reducing system was tolerant to several functional groups.
- Moriya, Toshimitsu,Yoneda, Shinichiro,Kawana, Keita,Ikeda, Reiko,Konakahara, Takeo,Sakai, Norio
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supporting information
p. 4842 - 4845,4
(2020/09/16)
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- Synthesis and characterization of ferroelectric liquid crystalline siloxanes containing 4-hydroxyphenyl(2S,3S)-2-chloro-3-methylvalerate
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New series of organosiloxane ferroelectric liquid crystalline materials have been synthesized, and their mesomorphic and physical properties have been characterized. These new series contain bis-siloxane or tris-siloxane unit attached to the flexible alkyl chain end of (2S,3S)-2-chloro-3-methylvalerate. The siloxane molecule induction is helpful to the chiral smectic C (S C) formation and chiral SC* stabilization, and it simultaneously causes the liquid crystal temperature range of chiral S C* to be broader. The siloxane member is helpful in reducing the smectic C (SC) transation shift temperature, and the molecule containing tris-siloxane units shows better effect than the bis-siloxane one. The synthesis and characterization of the new FLCs materials which exhibit SC* phase at room temperature and higher spontaneous polarization are presented.
- Lin, Chih-Hung
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experimental part
p. 33 - 42
(2012/05/04)
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- Decreasing the alkyl branch frequency in precision polyethylene: Pushing the limits toward longer run lengths
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A symmetrical α,ω-diene monomer with a 36 methylene run length was synthesized and polymerized, and the unsaturated polymer was hydrogenated to generate precision polyethylene possessing a butyl branch on every 75th carbon (74 methylenes between branch points). The precision polymer sharply melts at 104 °C and exhibits the typical orthorhombic unit cell structure with two characteristic wide-angle X-ray diffraction (WAXD) crystalline peaks observed at 21.5° and 24.0°, corresponding to reflection planes (110) and (200), respectively.
- Inci, Bora,Wagener, Kenneth B.
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supporting information; experimental part
p. 11872 - 11875
(2011/10/04)
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- New prodrugs of Adefovir and Cidofovir
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New Adefovir (PMEA) prodrugs with a pro-moiety consisting of decyl or decyloxyethyl chain bearing hydroxyl function(s), hexaethyleneglycol or a (5-methyl-2-oxo-1,3-dioxolen-4-yl)methyl unit were prepared starting from the tetrabutylammonium salt of the phosphonate drug and an appropriate alkyl bromide or tosylate. Analogously, two esters of Cidofovir [(S)-HPMPC] bearing a hexaethyleneglycol moiety were prepared. The activity of the prodrugs was evaluated in vitro against different virus families. A loss in the antiviral activities of the hydroxylated decyl or decyloxyethyl esters and hexaethyleneglycol esters of PMEA against human immunodeficiency virus (HIV) and herpesviruses [including herpes simplex virus (HSV), varicella-zoster virus (VZV), and human cytomegalovirus (CMV)] occurred in comparison with the parent compound. On the other hand, the (5-methyl-2-oxo-1,3-dioxolen-4-yl)methyl ester of PMEA showed significant activities against HIV and herpesviruses. (S)-HPMPC prodrugs exhibited anti-cytomegalovirus activities in the same range as the parent drug, whereas the anti-HSV and anti-VZV activities were one- to seven-fold lower than that of Cidofovir.
- Tichy, Tomá?,Andrei, Graciela,Dra?ínsky, Martin,Holy, Antonín,Balzarini, Jan,Snoeck, Robert,Kre?merová, Marcela
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experimental part
p. 3527 - 3539
(2011/07/09)
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- Oligoamide duplexes as organogelators
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Oligoamide duplexes carrying multiple alkyl side chains were found to serve as gelators for aromatic solvents. The double-stranded backbone was essential for the hierarchical self-assembly of the molecular duplex into fibers of high aspect ratios. The demonstrated gelating abilities may be extended to a large family of analogous H-bonded duplexes having different H-bonding sequences, leading to a unique platform for developing a diverse variety of potential gelators based on a supramolecular and/or a dynamic covalent approach.
- Cao, Ruikai,Zhou, Jingjing,Wang, Wei,Feng, Wen,Li, Xianghui,Zhang, Penghui,Deng, Pengchi,Yuan, Lihua,Gong, Bing
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supporting information; experimental part
p. 2958 - 2961
(2010/09/15)
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- Syntheses and palladium, platinum, and borane adducts of symmetrical trialkylphosphines with three terminal vinyl groups, P((CH2) mCH=CH2)3
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Reactions of Br(CH2)mCH=CH2 with Mg powder and then PCl3 (0.33 equiv.) afford P((CH2)m-CH=CH 2)3 (1; m = a, 4; b, 5; c, 6; d, 7; e, 8; f, 9; 52-87 %). Reactions of 1a-c, e with PdX2(COD) (X = Cl, Br) give trans-PdX 2(P((CH2)mCH=CH2)3) 2 (35-92 %). Reactions of 1b-e with PtCl2 in benzene give mainly trans-PtCl2(P((CH2)mCH=CH 2)3)2 (trans-5b-e; 52-75 %), whereas those with K2PtCl4 in water give mainly cis-5b-e (33-70 %). The reaction of equimolar quantities of 1c and H3B.S(CH3) 2 gives the 1 : 1 adduct H3B·P((CH 2)6CH=CH2)3 (85 %). In none of these transformations are by-products derived from the C=C linkages observed.
- Nawara-Hultzsch, Agnieszka J.,Skopek, Katrin,Shima, Takanori,Barbasiewicz, Micha,Hess, Gisela D.,Skaper, Dirk,Gladysz, John A.
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body text
p. 414 - 424
(2010/10/01)
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- Versatile and efficient synthesis of a new class of aza-based phosphinic amide ligands via unusual P-C cleavage
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A new class of bidentate, aza-based phosphinic amide ligands of the type RN(H)P(=O)(2-py)2 (2-py=2-pyridyl) was synthesized within minutes via a one-pot process including Staudinger reaction of an organic azide (RN 3) with 2-pyridylphosphines, followed by partial, unprecedented hydrolysis under loss of one aromatic substituent. The structure of the unusual-hydrolysis product H2C=CH(CH2)9N(H)P(= O)(2-py)2 (5a) was characterized by IR, 1H- and 31P-NMR, as well as by X-ray crystal-structure analysis (Figure). The tetrahedral P-atom was found to be surrounded by a trigonal-pyramidal arrangement of the substituents. To gain insight into the formation of these novel phosphinic amides, a series of intermediate iminophosphoranes, H 2C=CH(CH2)9N=P(Ar)n(2-py) 3-n (n = 0-3), compounds 1a-1f, were synthesized, and their hydrolyses were studied. All tested compounds followed the classical hydrolysis route of P=N cleavage under acidic conditions. Sequential hydrolysis to 5a-5d only occurred under either basic conditions or in wet MeCN as solvent. Notably, H2C=CH(CH2)9N=P(C6H 5)(4-MeO-2-py)2 (1c) was hydrolyzed at a much slower rate compared to its analogue 1b lacking the MeO group. On the contrary, the halogenated compounds H2C=CH(CH2)9N=P(4-X- C6H4)3 (1f,g) (X = F, Cl) were hydrolyzed at a notably faster rate relative to the non-halogenated congener 1e (X = H).
- Tsai, Shih-Chung,Fu, Yaw-Shien,Liao, Ju-Hsiou,Yu, Shuchun Joyce
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p. 3007 - 3017
(2007/10/03)
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- An original synthesis of highly ordered organosilica with a high content of thiol groups
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Well ordered bridged organosilica highly functionalised with disulfide groups were obtained by self-assembly of α,ω-bis(trimethoxysilyl) alkyldisulfide under hydrophilic conditions; the reduction of disulfide cores to SH groups gave rise to material having a high mercury ion adsorption capacity. The Royal Society of Chemistry 2006.
- Alauzun, Johan,Mehdi, Ahmad,Reye, Catherine,Corriu, Robert J. P.
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p. 347 - 349
(2008/02/08)
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- Silane molecules with pre-activated and protein-resistant functionalities and silane films comprising such molecules
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The present invention provides a silane molecule which combines pre-activated and protein-resistant functionalities in one molecule; the molecule has a general formula: A-(CH2)n—(O[CH2]t)m—(CH2)v—Y??(1) wherein A is a functional group for binding to a substrate and Y is a functional group for binding to biomolecules. The invention furthermore provides a method for the synthesis of such a silane molecule and a method for depositing a monolayer of such silane molecules onto a substrate. Such a monolayer of silane molecules may be used in biosensors, DNA/protein micro-arrays or other sensor applications. For further lowering the protein binding to the surface of the biosensor, the monolayer may furthermore comprise second silane molecules with formula: B—(CH2)o—(OCH2CH2)r-Z??(4)
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- Maleimido-terminated self-assembled monolayers
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Four approaches have been explored for the preparation of maleimido-functionalized self-assembled monolayers (SAMs) on silicon. SAMs prepared by self-assembly of maleimido-functionalized alkyltrichlorosilanes (11-maleimido-undecyl-trichlorosilane) on oxide-covered silicon yield higher signals from maleimido functionalities in ATR-IR (attenuated total reflection IR) spectroscopy and XPS (X-ray photoelectron spectroscopy) than the other three methods. The surface composition of maleimido groups was tailored further by the formation of mixed monolayers with nonfunctionalized alkyltrichlorosilanes (decyltrichlorosilane). The order of the alkyl chains within the monolayers only slightly depends on the composition of the mixed monolayers. We utilized the maleimido-terminated SAMs to bind various nucleophilic compounds, alkylamines, alkylthiols, and thiol-tagged DNA oligonucleotides by means of conjugate addition.
- Wang, Yayun,Cai, Jun,Rauscher, Hubert,Behm, Rolf Juergen,Goedel, Werner A.
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p. 3968 - 3978
(2007/10/03)
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- Cyclopropyl containing fatty acids as mechanistic probes for cytochromes P450
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(Chemical Equation Presented) The mechanism of aliphatic hydroxylation by cytochromes P450 has been the subject of intense debate with several proposed mechanistic alternatives. Various cyclopropyl containing compounds (radical clocks), which can produce both unrearranged and ring opened products upon oxidation, have been key tools in these investigations. In this study, we introduce several cyclopropyl containing fatty acids 1a-4a with which to probe the mechanism of P450s capable of fatty acid hydroxylation. The probes are shown to be capable of distinguishing radical from cationic intermediates due to the rapid equilibration of isomeric cyclopropyl cations. Ring opening of a radical intermediate in an oxidative transformation is expected to yield a single rearranged alcohol, whereas a cation isomerizes prior to ring opening, leading to two isomeric homoallylic alcohols. Oxidation of these probes by P450 BM3 and P450Biol gives results consistent with a radical but not a cationic intermediate in fatty acid hydroxylation by these enzymes. Quantitation of the unrearranged and ring opened products gives remarkably homogeneous rates for oxygen rebound of (2-3) × 1010 s -1. The effects of introduction of a cyclopropane ring into a fatty acid upon the regiochemistry of hydroxylation are discussed.
- Cryle, Max J.,Ortiz De Montellano, Paul R.,De Voss, James J.
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p. 2455 - 2469
(2007/10/03)
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- The facile preparation of alkenyl metathesis synthons
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We report synthetic methodology allowing the preparation of any length alkenyl halide from inexpensive starting reagents. Standard organic transformations were used to prepare straight chain α-olefin halides in excellent overall yields with no detectable olefin isomerization and full recovery of any unreacted starting material. Reported transformations can be used for the selective incorporation of pure α-olefin metathesis sites in highly functionalized molecules.
- Baughman, Travis W.,Sworen, John C.,Wagener, Kenneth B.
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p. 10943 - 10948
(2007/10/03)
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- Ester type banana-shaped liquid crystalline monomers: Synthesis and physical properties
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New ester-type banana (bent-shaped) monomers, 1,3-phenylene bis[4′-(alken-1-yloxy)-biphenyl-4-carboxylate]s Ia-Vb, with different substituent(s) on the central phenyl ring (H, CH3, Cl or NO 2) and alkenyl tails in the side arms (decenyl or undecenyl) were prepared. The analogues IIIa-IVb with 4-chloro- or 4,6-dichloro-substituents exhibited a nematic phase, while Va,Vb with 2-nitro-substituent showed a B 7 phase at relatively low temperature. All the compounds were stable, no degradation or polymerization was observed under applied electric fields or heat treatments. Electro-hydrodynamic instabilities were observed in the nematic phase of each sample. In the B7 phase of Vb there was an electro-optical switching in the range 112-114.5 °C with a switching time of about 150 μs at 20 V μm-1 field. At lower temperatures no electro-optical switching occurred, but a ferroelectric-type spontaneous polarization of 22 nC cm-2 could be detected. The bend angle was calculated by the semiempirical CAChe/MOPAC/PM5 method.
- Fodor-Csorba, Katalin,Vajda, Aniko,Jakli, Antal,Slugov, Christian,Trimmel, Gregor,Demus, Dietrich,Gacs-Baitz, Eszter,Holly, Sandor,Galli, Giancarlo
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p. 2499 - 2506
(2007/10/03)
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- Ionic liquids as reagents and solvents in conjunction with microwave heating: Rapid synthesis of alkyl halides from alcohols and nitriles from aryl halides
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We show that using ionic liquids as reagents in conjunction with microwave heating it is possible to prepare primary alkyl halides from the corresponding alcohols rapidly. Using ionic liquids as solvents in conjunction with microwave heating it is possible to prepare aryl nitriles from the corresponding aryl bromides or iodides. The scope and limitations of using microwave-promotion as a tool in these reactions is discussed.
- Leadbeater, Nicholas E.,Torenius, Hanna M.,Tye, Heather
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p. 2253 - 2258
(2007/10/03)
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- Chain-modified pyridino-N substituted nicotine compounds for use in the treatment of CNS pathologies
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Compounds for treating abuse of nicotinic receptor agonists, addiction to psychostimulant drugs, addiction to opiates, addiction to alcohol, addiction to tobacco products, addiction to nicotine, schizophrenia and related diseases, depression and related conditions, Alzheimer's disease, Parkinson's disease, irritable bowel syndrome, and colitis. The compounds competitively inhibit central nervous system acting nicotinic receptor agonists and act at the putative α3β2* and α4β2 neuronal nicotinic receptors in the central nervous system.
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- Evaluation of exo-endo ratios in the halolactonization of ω-unsaturated acids
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The reaction of 2-(ω-alkenyl)benzoic acids with bis(collidine)iodine and bis(collidine)bromine hexafluorophosphate was examined. Except with 2-but-3-enylbenzoic acid, for which only the exo lactone was obtained, for the other acids a mixture of exo-endo lactones was always obtained. The proportion of endo lactone was important for the acid chain length of 11 carbons (formation of a 12-membered ring endo lactone) and for the acid chain lengths higher than 14 carbons. The formation of the endo lactones was explained, on the base of molecular calculations, by competition between electronic and steric effects. These latter were developed by transannular interactions (for the acid chain lengths 8-11) and/or the conformations adopted by the chains (for the acid chain lengths ≥ 14,) which disfavored the formation of the exo lactones. The larger proportion of endo lactones observed with the bromo reagent compared to the iodo reagent seemed due to electronic factors.
- Roux,Paugam,Rousseau
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p. 4304 - 4310
(2007/10/03)
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- High surface density covalent immobilization of oligonucleotide monolayers using a 1-(thiotrifluoroacetato)-11-(trichlorososilyl)-undecane linker
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Oligonucleotides and other biomolecules are immobilized in high density on solid substrates through covalent forces using either a permanent thioether bond, or a chemoselectively reversible disulfide bond to a surface thiol. Substrates which have hydroxyl groups on their surfaces can be first silanized with a trichlorosilane containing 2-20 carbon atoms in its hydrocarbon backbone, terminating in a protected thiol group. The oligonucleotides or other biomolecules are first connected to a tether consisting of a hydrocarbon or polyether chain of 2-20 units in length which terminates in a thiol group. This thiol may be further modified with a halobenzylic-bifunctional water soluble reagent which allows the conjugate to be immobilized onto the surface thiol group by a permanent thioether bond. Alternatively, the oligonucleotide-tether-thiol group can be converted to a pyridyldisulfide functionality which attaches to the surface thiol by a chemoselectively reversible disulfide bond. The permanently bound oligonucleotides are immobilized in high density compared to other types of thiol functionalized silane surfaces and to the avidin-biotin method.
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- Synthesis and characterization of tris-methacrylated 3,4,5- tris[(alkoxy)benzyloxy]benzoate derivatives
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The synthesis of liquid crystalline 3,4,5-tris(11-methacryloylundecyl-1- oxybenzyloxy)benzoic acid, 2-methyl-(1,4,7,10,13-pentaoxacyclopentadecane)- 3,4,5-tris[4-(11-methacryloylundecyl-1-oxy)benzyloxy] benzoate and its 1:1 complex with sodium triflate is described. The observed mesophases were identified, by polarized optical microscopy and contact preparation techniques, to be of hexagonal columnar disordered structure. The amphiphiles form lyotropic columnar phases in concentrated methacrylate solvents, while at low solute contents supramolecular organogels emerge.
- Beginn, Uwe,Zipp, Gabriela,Moeller, Martin
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p. 2016 - 2023
(2007/10/03)
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- Thiol functionalization of surfaces for biosensor development
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The immobilization of biomolecules on substrate surfaces for biosensor development requires linking molecules that must meet a specific set of criteria. Two such agents based on bifunctional alkyltrichlorosilane structures, 1-bromo-11-(trichlorosilyl)-undecane and 1-(thiotrifluoroacetato)-11-(trichlorosilyl)-undecane, are employed to generate thiol-functionalized surfaces either by nucleophilic substitution followed by reduction (bromine-containing derivative) or deprotection (fluorine-containing compound). Both molecules have been attached to the surfaces of silicon wafers in conjunction with the diluent silane, octyltrichlorosilane. X-ray photoelectron spectroscopic analysis in the conventional and angle-resolved modes confirms that both silanization reactions were successful. The alkyl-bromine surfaces were subjected to treatment with a set of nucleophilic reactants followed by reduction and derivatization with trifluoroacetic anhydride. The latter in conjunction with surface analysis was used to estimate the level of thiol functionalization achieved. The fluorine-containing undecane surface has been studied by surface analysis both before and after deprotection of the thiol group by hydroxylamine solution. The results indicate that a high coverage of the surface was found for the protected moiety, with approximately 10% of the trifluoro acetate groups remaining after the deprotection procedure.
- McGovern, Mark E.,Thompson, Michael
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p. 1678 - 1689
(2007/10/03)
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- Synthesis of racemic and each enantiomer of 3-methylnonacosanol, a new plant growth regulator from Lowsonia inermis
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An efficient synthesis of the title compound I in racemic and enantiomeric forms has been developed starting from 10-undecenoic acid. For the enantiomeric synthesis, a lipase catalyzed acylation strategy was employed to prepare the required methyl branched chiron which was subsequently derivatized to give the enantiomers of I. The plant growth regulatory (PGR) assay of I, carried out with hypocotyl cuttings of French beans (Phaseolus vulgaris L.) in Steinberg's nutrient medium revealed appreciable activity at a concentration of 2.5 ppm. The PGR activities of the compound both in racemic and enantiomeric forms were better than 1- triacontanol, the enantiomer, (S)-I being the best test candidate.
- Kulkarni, Bheemashankar A.,Sankaranarayanan, Sivaraman,Subbaraman, Ayalur S.,Chattopadhyay, Subrata
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p. 1571 - 1577
(2007/10/03)
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- Efficient synthesis of 40- and 48-membered tetraether macrocyclic bisphosphocholines.
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An efficient route toward the synthesis of unsaturated (bis-diacetylenic) and saturated 40- and 48-membered macrocyclic biphosphocholines has been developed using 2-phenyl-5-hydroxy-1,3-dioxane as a common glycerol synthon. Ring closure was accomplished using either high-dilution Glaser oxidation of [(Cy3P)2RU==CHPh]Cl2-catalyzed olefin metathesis conditions. Deprotection of benzyl ethers using trimethylsilyl iodide (TMS-I) in the presence of diacetylenic moieties has also been demonstrated for the first time.
- Patwardhan,Thompson
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p. 241 - 243
(2008/02/13)
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- A new method for the preparation of olefins from vicinal diols
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A novel method is reported for the transformation of vicinal diols to olefins. This methodology consists in the conversion of iodothiocarbonates such as 16 to olefin 17 with phenyl lithium in excellent yield. Compounds 7 and 12 were prepared by this methodology in order to determine if they would be recognized by the enzymes, 5-lipoxygenase and 15-lipoxygenase, respectively.
- Adiyaman, Mustafa,Jung, Young-Ju,Kim, Seongjin,Saha, Goutam,Powell, William S.,FitzGerald, Garret A.,Rokach, Joshua
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p. 4019 - 4022
(2007/10/03)
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- Efficient conditions for conversion of 2-substituted furans into 4-oxygenated 2-enoic acids and its application to synthesis of (+)-aspicilin, (+)-patulolide a, and (-)-pyrenophorin
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2-Substituted furans 1a,b,c were found to be conveniently transformed into trans 4-oxo-2-enals 2a,b,c in 62-87% yields by using NBS/pyridine in THF-acetone-H2O (3 in acetone-H2O (2 led to the trans 4-oxo-2-enoic acids 3a-c in good yields. With this transformation in mind, we designed syntheses of (+)-aspicilin, (+)-patulolide, and (-)-pyrenophorin. In the synthesis of (+)-aspicilin as shown in Schemes 1 and 2, the pivotal intermediate 6 was prepared from olefin 7 in which 2-furyl group is attached. The AD reaction of 7 secured the C(5) and C(6) stereochemistry of aspicilin, and the subsequent transformation using the protocol described above afforded the ester 6. Stereocontrolled reduction of 6 followed by deprotection and the Yamaguchi macrocyclization furnished (+)-aspicilin. For the synthesis of (+)-patulolide (Scheme 3) and (-)-pyrenophorin (Scheme 4), the intermediates are the furans 38 and 44, which were prepared easily by the classical methods using furyllithium 33. The furan ring oxidations proceeded as well, furnishing acids 40 and 46 in good yields, acetalization of which afforded the known intermediates 41 and 47, respectively.
- Kobayashi, Yuichi,Nakano, Miwa,Biju Kumar,Kishihara, Kiyonobu
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p. 7505 - 7515
(2007/10/03)
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- Direct transformation of sterically less hindered silyl ethers to the corresponding bromides with inversion of configuration
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The phosphonium salt 2, generated by adding 2,4,4,6-tetrabromo-2,5-cyclohexadienone1 to triphenylphosphine in CH3CN-THF or 1,2-dichloroethane converted sterically less congested silyl ethers directly to the corresponding bromides in high yields.
- Tanaka, Akira,Oritani, Takayuki
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p. 7223 - 7224
(2007/10/03)
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- An efficient method for converting alcohols to azides with 2,4,4,6-tetrabromo-2,5-cyclohexadienone/PPh3/Zn(N3)2·Py
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Treatment of the salt generated from 2,4,4,6-tetrabromo-2,5-cyclohexadienone and PPh3 in a mixed solvent of CH3CN/toluene with primary and secondary alcohols in the presence of Zn(N3)2·Py led to azides in excellent yields with inversion of configuration. Addition of hexamethylphosphorictriamide considerably accelerated the reaction.
- Saito, Akiko,Saito, Kazumi,Tanaka, Akira,Oritani, Takayuki
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p. 3955 - 3958
(2007/10/03)
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- Synthesis of Saturated Anacardic Acids, and Alkenyl and Alkynyl Analogues
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The C-alkylation of esters of 2-methoxy-6-methylbenzoic acid and of the 4-methyl isomers affords a route to homologous compounds including in the former case members of the natural anacardic acids from Anacardium occidentale and ω-alkynyl compounds suitable for synthesising other natural phenolic lipids or for structure/activity studies.
- Tyman, John H. P.,Visani, Naina
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p. 228 - 240
(2007/10/03)
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- Polyanion Inhibitors of Human Immunodeficiency Virus and Other Viruses. 1. Polymerized Anionic Surfactants
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A series of polyanionic compounds was synthesized and evaluated for their activity against human immunodeficiency virus (HIV-1, HIV-2) and various other RNA and DNA viruses.Several compounds, i.e., 2p, 3p, 8p, 13p, 14p, 15p, 17p, 18p, and 19p, proved active against HIV-1 within the concentration range of 0.1-3μg/mL while not being toxic to the host cells (CEM, MT-4) at concentrations up to 100 μg/mL or higher.As a rule, these polyanionic compounds proved also active, albeit at somewhat higher concentrations than those required for HIV-1 inhibition, against a number of other enveloped viruses, including HIV-2, human cytomegalovirus, influenza A virus, respiratory syncytial virus, and arenaviruses (Junin and Tacaribe).Among the most potent HIV-1 inhibitors ranked compounds 18p and 19p, the sodium salts of N-methylamides obtained by polymerization of monomers prepared starting from 10-undecenoyl chloride and ω-aminoalkanoic acids.
- Leydet, A.,Barthelemy, Ph.,Boyer, B.,Lamaty, G.,Rogue, J. P.,et al.
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p. 2433 - 2440
(2007/10/02)
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- Initiation and bonding of diamond and other thin films
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A method for initiating and bonding thin films on substrates is described. The method employs an interlayer comprising a self-assembling monolayer (SAM). The SAM is formed from monomers, one end of which are capable of bonding to the substrate, and the other end of which form a surface similar to, and capable of initiating the formation of a film. Additionally, compositions for monomers, methods for SAM formation, and methods for film formation are disclosed. In a preferred embodiment the thin film is comprised of diamond.
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- Monofunctional chiral crowns. Part 1
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A siloxane oligomer bearing a chiral crown with high affinity for α-amino acids has been synthesised. The host is a modified form of a coronand first prepared by Cram, in which two 1,1'-binaphthol systems are linked through the oxygen atoms at the 2,2'-positions to form a 22-membered ring system containing six ether oxygen atoms attached to each other by four ethylene units. This was selectively mono-alkenylated to form an undec-10-en-1-yl derivative, which was bonded to linear siloxanes [HSiMe2O(SiMe2O)(n)SiMe2H] and [Me3SiO(Me2SiO)(x)(MeHSiO)(y)SiMe3] with total chain lengths of ca 4 and 200 Si atoms respectively, via a Pt catalysed hydrosilylation reaction.
- Brisdon,England,Reza,Sainsbury
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p. 1103 - 1114
(2007/10/02)
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- A CONVENIENT AND EFFICIENT THREE-STEP SYTHESIS OF α-CHLORO KETO ACIDS
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Efficient three-step syntheses of α-chloro keto acids 1a-c from ω-alkenoic acids 2 and ω-alkenyl alcohols 3 are described, proceeding via epoxidation/chloride-mediated epoxide ring opening/Jones oxidation protocols.
- Chai, Ki-Byung,Sampson, Paul
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p. 585 - 588
(2007/10/02)
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- Cyclization of 9-Substituted Decanoic Acid Derivatives to 9-Decanolide and 9-Decanelactam
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Several standard and some novel cyclization reactions have been applied to 9-substituted decanoic acids to establish which are the optimum procedures for lactonization and lactamization at 80 deg C under identical high-dilution conditions.The methods of Galli-Mandolini and Kellogg (cyclization of 9-bromodecanoate ion), Gerlach (cyclization of S-2-pyridyl 9-hydroxydecanethioate in the presence of AgClO4), and Yamaguchi (activation of the carboxyl group as a mixed anhydride) in the presence of an excess of DMAP appear to be the most useful for the preparation of the 10-membered lactone, phoracantolide I, under these conditions.Analogously, treatment of S-2-pyridyl 9-azidodecanethionate with Sn(SePh)3(1-) afforded the best yield of the 10-membered lactam.The mixed anhydrides RCOOCOAr (Ar = 2,4,6-trichlorophenyl) are more reactive than thioesters RCOSPy (Py = 2-pyridyl) with benzyl alcohol or benzylamine; it is confirmed that the addition of DMAP activates the reaction of alcohols with mixed anhydrides much more than with pyridyl thioesters, while the addition of Ag(1+) strongly activates RCOSPy in relation to either RCOOCOAr or RCOOSO2Mes.
- Bartra, Marti,Vilarrasa, Jaume
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p. 5132 - 5138
(2007/10/02)
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- Perfluorinated analogues of poison ivy allergens. Synthesis and skin tolerogenic activity in mice
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3-(Tridecafluoroundecyl)catechol (8) and 3-(nonafluoropentadecyl)catechol (9), perfluorinated analogues of pentadecylcatechol (PDC), a constituent of poison ivy, have been synthesized. These compounds were nonsensitizers in mice. Compounds 8 and 9, however, were elicitors of allergic contact dermatitis in PDC-sensitized animals. Moreover, compound 9 exhibited tolerogenic properties to sensitization by poison ivy allergens, i.e. mice pretreated with perfluorinated compounds could not be sensitized to PDC.
- Fraginals,Schaeffer,Stampf,Benezra
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p. 1024 - 1027
(2007/10/02)
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- Convergent approaches to the syntheses of long-chain aliphatic hydroxy ketones: Potential bioactive compounds of plant origin
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Convenient synthesis of hexacosan-25-one-1-ol (I), 8-hydroxydotriacontan-30-one (II) and 8-hydroxydotriacontan-27-one (III) have been achieved.Grignard coupling between undecenylmagnesium bromide and bromopyranyloxy compounds (6) and (7) in the presence of Li2CuCl4 give the corresponding products (10) and (11).Alcohol (10) is converted into its corresponding bromides (12) and aldehyde (16) and alcohol (11) to bromide (14).Further Grignard coupling between 9 and 12, followed by Pd(II) oxidation furnishes I.The Grignard reagent of 14 on treatment with propionyl chloride gives 15 and the reaction of phenylmagnesium bromide with 16 followed by PCC oxidation gives 18.These on epoxidation followed by oxidative ring cleavage yield the corresponding aldehydes (21) and (22).The reaction of 21 and 22 with heptylmagnesium bromide afford the corresponding II and III.
- Iyer, R. R.,Mamdapur, V. R.
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p. 728 - 732
(2007/10/02)
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- FUNCTIONALIZED SILOXY-ANCHORED MONOLAYERS WITH EXPOSED AMINO, AZIDO, BROMO, OR CYANO GROUPS
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The creation of new, uniformly functionalized, surfaces has been achieved with monolayers bearing NH2, N3, Br, or CN functional groups.
- Balachander, Natarajan,Sukenik, Chaim N.
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p. 5593 - 5594
(2007/10/02)
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- A New and Efficient One-Pot Preparation of Alkyl Halides From Alcohols
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Primary alkanols and 2-alkenols are converted into the corresponding halides in high yield by a one-pot, two-step reaction via transformation into intermediate trifluoroacetates followed by nucleophilic substitution with lithium halides.
- Camps, Francisco,Gasol, Vicens,Guerrero, Angel
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p. 511 - 512
(2007/10/02)
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- Synthesis of 14-Methylpentadecan-3-one
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An unambiguous synthesis of the title compound (9), isolated recently by Haque et al. from the pet. ether extract of Parthenium hysterophorous Linn. is described.Significantly the natural compound has been isolated as a solid (m.p. 80 deg C) while our synthetic product is an oil (b.p. 118-20 deg C/0.4 mm).Besides this some of the reported spectral data do not tally with those of synthetic 9.
- Trivedi, S. V.,Mamdapur, V. R.
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p. 176 - 177
(2007/10/02)
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- Synthesis of Various New Nitroxide Free Radical Fatty Acids
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A generally applicable method is presented for the synthesis of various new nitroxide fatty acid isomers in which the fatty acid chains are attached at different positions of the pyrrolidin-1-oxyl ring.These isomers can be obtained by Michael addition of a nitroalkane to an α,β-unsaturated ketone to give a γ-nitro ketone, followed by ring closure with zinc and ammonium chloride to give a 1-pyrroline N-oxide which then reacts with Grignard reagents to give a pyrrolidin-1-oxyl free radical compound, which undergoes phase transfer oxidation of its terminal unsaturated bond.
- Hideg, Kalman,Lex, Laszlo
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p. 1431 - 1438
(2007/10/02)
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- Convenient Synthesis of 4-Acetyl-2-methoxy-5-methyl-triacontane and 23-Hydroxytriacontan-2-one, the Constituents of Curculigo orchioides
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Unambiguous syntheses of the two title compounds (I) and (II), recently isolated by Mehta et al. and Misra et al. from Curculigo orchioides are reported.The syntheses use the Grignard coupling of undecenyl bromide with cetyl bromide (2) and monobromo pyranyl ether (10) of dodecanediol, respectively as one of the key reactions.Further elaboration of the products in each case leads to the desired compounds (I) and (II).Complete identity of the synthetic products with the natural ones, however, could not be established.
- Iyer, R.,Mamdapur, V. R.,Chadha, M. S.
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p. 887 - 890
(2007/10/02)
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