- Molecularly imprinted artificial esterases with highly specific active sites and precisely installed catalytic groups
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A difficult challenge in synthetic enzymes is the creation of substrate-selective active sites with accurately positioned catalytic groups. Covalent molecular imprinting in cross-linked micelles afforded such active sites in protein-sized, water-soluble nanoparticle catalysts. Our method allowed a systematic tuning of the distance of the catalytic group to the bound substrate. The catalysts displayed enzyme-like kinetics and easily distinguished substrates with subtle structural differences.
- Hu, Lan,Zhao, Yan
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supporting information
p. 5580 - 5584
(2018/08/17)
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- Selective Monomethylation of Amines with Methanol as the C1 Source
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The N-monomethyl functionality is a common motif in a variety of synthetic and natural compounds. However, facile access to such compounds remains a fundamental challenge in organic synthesis owing to selectivity issues caused by overmethylation. To address this issue, we have developed a method for the selective, catalytic monomethylation of various structurally and functionally diverse amines, including typically problematic primary aliphatic amines, using methanol as the methylating agent, which is a sustainable chemical feedstock. Kinetic control of the aliphatic amine monomethylation was achieved by using a readily available ruthenium catalyst at an adequate temperature under hydrogen pressure. Various substrates including bio-related molecules and pharmaceuticals were selectively monomethylated, demonstrating the general utility of the developed method.
- Choi, Geunho,Hong, Soon Hyeok
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supporting information
p. 6166 - 6170
(2018/04/30)
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- High power organic cathodes using thin films of electropolymerized benzidine polymers
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Thin films of benzidine polymers were electrochemically deposited directly onto conductive substrates by oxidative coupling of di- and trianilinoalkane monomers. The electropolymerization and electrochemical properties of the polymers were optimized by varying the alkyl linker. Polymer films exhibited two reversible one-electron transfers at high potentials (>3.3 V vs. Li/Li+) and maintained discharge capacities in excess of 150 mA h g-1 even when discharged in under 4 seconds.
- Truong, Thanh-Tam,Coates, Geoffrey W.,Abru?a, Héctor D.
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supporting information
p. 14674 - 14677
(2015/09/28)
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- In vitro cytotoxicity on human ovarian cancer cells by T-type calcium channel blockers
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The growth inhibition of human cancer cells via T-type Ca2+ channel blockade has been well known. Herein, a series of new 3,4-dihydroquinazoline derivatives were synthesized via a brief SAR study on KYS05090 template and evaluated for both T-type Ca2+ channel (Ca v3.1) blockade and cytotoxicity on three human ovarian cancer cells (SK-OV-3, A2780 and A2780-T). Most of compounds except 6i generally exhibited more potent cytotoxicity on SK-OV-3 than mibefradil as a positive control regardless of the degree of T-type channel blockade. In particular, eight compounds (KYS05090, 6a and 6c-6h) showing strong channel blockade exhibited almost equal and more potent cytotoxicity on A2780 when compared to mibefradil. On A2780-T paclitaxel-resistant human ovarian carcinoma, two compounds (KYS05090 and 6d) were 20-fold more active than mibefradil. With respect to cell cycle arrest effect on A2780 and A2780-T cells, KYS05090 induced large proportion of sub-G1 phase in the cell cycle progression of A2780 and A2780-T, meaning the induction of cancer cell death instead of cell cycle arrest via blocking T-type Ca2+ channel. Among new analogues, compounds 6g and 6h induced cell cycle arrest at G1 phase of A2780 and A2780-T cells in dose-dependent manner and exhibited strong anti-proliferation effects of ovarian cancer cells by blocking T-type Ca2+ channel. Furthermore, 6g and 6h possessing strong cytotoxic effects could induce apoptosis of A2780 cells, which was detected by confocal micrographs using DAPI staining.
- Jang, Sun Jeong,Choi, Heung Woo,Choi, Doo Li,Cho, Sehyeon,Rim, Hong-Kun,Choi, Hye-Eun,Kim, Ki-Sun,Huang, Minghua,Rhim, Hyewhon,Lee, Kyung-Tae,Lee, Jae Yeol
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p. 6656 - 6662
(2014/01/06)
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- Stereoselective aldol additions of achiral ethyl ketone-derived trichlorosilyl enolates
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Methods for the preparation of geometrically defined enoxy(trichlorosilanes) derived from ethyl ketone enolates have been developed. The addition of enoxy(trichlorosilanes) (trichlorosilyl enolates) to aldehydes proceeds with good yields in the presence of catalytic amounts of chiral phosphoramides. The reaction of Z-trichlorosilyl enolates to aryl aldehydes affords aldol products with good to excellent diastereo- and enantioselectivities. Phosphoramide-catalyzed aldol additions lacked substrate generality providing modest selectivities with unsaturated and aliphatic aldehydes. In all cases, the phosphoramide-catalyzed aldol addition of E-trichlorosilyl enolates to aldehydes provided good yields with moderate to good stereoselectivities.
- Denmark, Scott E.,Pham, Son M.
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p. 5045 - 5055
(2007/10/03)
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- LOCAL ANESTHETIC COMPOUNDS AND USES
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Novel compounds, pharmaceutical compositions and methods are disclosed for producing local anesthesia of long-duration. The compounds of this invention are multibinding compounds that comprise from 2 to 10 ligands covalently attached to a linker or linkers, each ligand being capable of binding to a ligand binding site in a voltage-gated Na + channel to modulate the biological processes/functions thereof.
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- Condensation of Alkanediamines with Formaldehyde; Intramolecular Disproportionation of N-Hydroxymethyl Groups into N-Methyl and N-Formyl Groups
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The condensation of α,ω-alkanediamines NH2(CN2)nNH2 with aqueous formaldehyde has been studied by NMR spectroscopy of isolated products and of product mixtures.The condensation was reversible and gave products of widely different types depending on alkane chain length: bicyclic oxadiaza compounds (n = 2, 3, 4), a tricyclic tetraaza compound (n = 2), a quinquecyclic octaaza compound (n = 3), two-dimensional polymers (n = 4, 5).A slow irreversible rearrangement gave in two cases (n = 3, 4), unicyclic 1-formyl-3-methyl-1,3-diaza compounds.The condensation of N,N'-dimethyl-α,ω-alkandediamines CH3NH(CH2)nNHCH3 with aqueous formaldehyde was also studied.The reversible formation of simple unicyclic diaza compounds was observed in all cases (n = 2, 3, 4), but in one case (n = 2) there was again a slow irreversible rearrangement to the N-formyl-N,N'N'-trimethyl derivative.The rearrangement reaction involves a hydride shift and is strictly intramolecular.The conditions for its occurrence can be understood on a conformational basis.
- Dale, Johannes,Sigvartsen, Turid
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p. 1064 - 1070
(2007/10/02)
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- CONVENIENT ROUTES TO ALKYL-SUBSTITUTED POLYAMINES
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Alkyl-substituted polyamines, valuable for biological studies, can be prepared from N-phenylmethoxycarbonyl-1,4-diaminobutane (1b) and N-phenylmethoxycarbonyl-4-azidobutanamine (4a) by utilising the following reactions: (i) reduction of the phenylmethoxycarbonyl group to methyl by borane and (ii) combination of the Staudinger and aza-Wittig reactions .
- Golding, Bernard T.,O"Sullivan, Mary C.,Smith, Lewis L.
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p. 6651 - 6654
(2007/10/02)
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