- Synthesis and DNA-Sequence Selectivity of a Series of Mono- and Difunctional 9-Aminoacridine Nitrogen Mustards
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The aim of this work was to identify nitrogen mustards that would react selectively with DNA, particularly in G-rich regions.A series of mono- and difunctional nitrogen mustards was synthesized in which the (2-chloroethyl)amino functions were connected to the N9 of 9-aminoacridine by way of a spacer chain consisting of two to six methylene units.The length of the spacer chain connecting the alkylating and putative DNA-intercalating groups was found to affect the preference for the alkylation of different guanine-N7 positions in a DNA sequence.All of the compounds reacted preferentially at G's that are followed by G as do most other types of nitrogen mustards, but the degree of selectivity was greater.The compounds reacted at much lower concentrations than were required for comparable reaction by mechlorethamine (HN2), consistent with initial noncovalent binding to DNA prior to guanine-N7 alkylation.The degree of DNA-sequance selectivity increased as the spacer-chain length decrease below four methylene units.Most strikingly, long spacer compounds reacted strongly at 5'-GT-3' sequences, whereas this reaction was almost completely suppressed when the spacer length was reduced to two or three methylenes.Mono- and difunctional compounds of a given spacer length showed no consistent difference in DNA-sequence preference.
- Kohn, Kurt W.,Orr, Ann,O'Connor, Patrick M.,Guziec, Lynn James,Guziec, Frank S.
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- Synthesis and shape memory behavior study of hyperbranched poly(urethane-tetrazole)
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A novel hyperbranched poly(urethane-tetrazole) (HPUTZ) was synthesized via the "A2+BB2′ " approach using hexadiisocyanate (HDI) and 3-(bis-(2-hydroxyethyl)) aminopropyltetrazole (HAPTZ). The molecular structure was characterized by FTIR and 1H NMR spectroscopy. The number average molecular weight was measured to be 1.05×104 g/mol with a polydispersity of 1.27 by GPC analysis. The HPUTZ was further cured by the semi-adduct (PEG-IPDI) from polyethylene glycol (PEG) reacting with isophorone diisocyanate (IPDI) to form the crosslinked HAPTZ-PU film in different ratio of HAPTZ to PEG-IPDI. The glass transition temperature of HAPTZ-PU increased from 44.9 to 56.4 °C as the HPUTZ content increased from 20% to 33% from the DSC analysis. The DMA results indicated that the HPUTZ-PU with 20% HPUTZ possessed the highest storage modulus and loss tangent. However, the storage modulus increased with the increasing of HPUTZ segment at higher temperature. The shape memory study showed that all the films presented the excellent shape memory function. Over 98% shape recovery could be obtained for the HAPTZ-PU with 20%-33% HAPTZ segment content within 60 s in the tension deformation test and within 40 s at 80 °C in the bend deformation test.
- Qiao, LiGen,Asif, Anila,Shi, WenFang
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- Cobalt complexation with unsymmetrical tripodal ligands
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The reaction of the aliphatic unsymmetrical tripod [N(CH2CH 2NH2)2(CH2CH2OH)], H 5-1, with cobalt(II) chloride in THF yields after aerial oxidation the dinuclear complex [(H4-1)CoIII(μ-OH)Co III(H4-1)](CoIICl4)Cl, [5](CoCl 4)Cl. The trianion 53- contains two cobalt atoms triply bridged by two alkoxo groups of the singly deprotonated ligand (H 4-1)- and a hydroxo group. The new ligand [N(CH 2CH2CH2NH2)(CH2CH 2OH)2], H4-3, providing an N2O 2 donor set reacts with cobalt(II) chloride to give after aerial oxidation the hexanuclear complex [CoIII4(H 2-3)4CoII2(HOMe)2Cl 2(μ-OH)4], [6]Cl2, containing an unprecedented mixed-valent CoIII4CoII 2 core.
- Jocher, Christoph,Pape, Tania,Hahn, F. Ekkehardt
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- POSITIVE RESIST COMPOSITION AND PATTERNING PROCESS
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A positive resist composition comprises (A) a resin component which becomes soluble in an alkaline developer under the action of an acid and (B) an acid generator. The resin (A) is a polymer comprising recurring units containing a non-leaving hydroxyl group represented by formula (1) wherein R1 is H, methyl or trifluoromethyl, X is a single bond or methylene, m is 1 or 2, and the hydroxyl group attaches to a secondary carbon atom. The composition is improved in resolution when processed by lithography.
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- Iodine-alumina catalyzed Aza- michael addition under solvent free conditions
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An efficient aza-Michael addition of amines to a variety of activated olefins was carried out under solvent free conditions using iodine-alumina as a catalyst at room temperature or under microwave irradiation (in case of solid) in high yield. 2009 Bentham Science Publishers Ltd.
- Saikia, Monmi,Kakati, Dwipen,Joseph, Maria Stalin,Sarma, Jadab Chandra
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experimental part
p. 654 - 658
(2010/06/15)
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- Novel tertiary (meth)acrylates having lactone structure, polymers, resist compositions and patterning process
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Novel tertiary (meth)acrylate compounds having a lactone structure are polymerizable into polymers having improved transparency, especially at the exposure wavelength of an excimer laser and dry etching resistance. Resist compositions comprising the polymers are sensitive to high-energy radiation, have a high resolution, and lend themselves to micropatterning with electron beams or deep-UV rays.
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