- Oxetane-terminated telechelic epoxy-functional polyesters as cationically polymerizable thermoset resins: Tuning the reactivity with structural design
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A series of epoxy-functional telechelic oligomers containing oxetane end groups have been synthesized. The precursor monomer, extracted from outer Birch bark, was first polymerized through enzyme-catalyzed esterification to form oligomers having epoxy and/or oxetane groups in the structures. The oligoesters were subsequently crosslinked through cationic polymerization either by epoxy or oxetane homopolymerization or copolymerization when both functionalities were present. A study of the polymerizations of the resins was performed "in situ" using real-time Fourier transform infrared spectroscopy revealing a preferred copolymerization when compared with the homopolymerization. By tailoring the different structures, it was possible to control the final mechanical properties of the networks.
- Torron, Susana,Johansson, Mats
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- Six New Polyacetylenic Alcohols from the Marine Sponges Petrosia sp. and Halichondria sp.
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Six new polyacetylenic alcohols, termed strongylotriols A and B; pellynols J, K, and L; and isopellynol A, together with three known polyacetylenic alcohols, pellynols A, B, and C were isolated from the marine sponges Petrosia sp., and Halichondria sp. collected in Okinawa, Japan. Their planer structures were determined based on 2D-NMR and mass spectrometric analysis of the degraded products by RuCl3 oxidation. The absolute stereochemistry of isolates was examined by their Mosher's esters. The strongylotriols were found to be optically pure compounds, whereas the pellynols are diastereomeric mixtures at the C-6 position. Proliferation experiments using the HeLa and K562 cell lines suggested that the essential structural units for activity are the "hexa-2,4-diyn-1,6-diol" and "pent-1-en-4-yn-3-ol" on the termini.
- Gabriel, Adeyemi Francis,Li, Zhen,Kusuda, Ryouhei,Tanaka, Chiaki,Miyamoto, Tomofumi
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p. 469 - 475
(2015/09/07)
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- On the search of new I2-IBS aliphatic ligands: Bis-guanidino carbonyl derivatives
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Continuing with our search of aliphatic dicationic derivatives as I2-IBS ligands and looking at Amiloride, a known ligand of I2-IBS, we have incorporated the guanidinocarbonyl moiety into our aliphatic compounds with the intention of improving the binding to I2-IBS. Thus, we present the different approaches to the preparation and pharmacological evaluation (in human brain tissue) as I2-IBS ligands of a new series of aliphatic derivatives incorporating the guanidinocarbonyl group and with different chain length (n = 8-12, and 14 methylene groups).
- Corcoran, Jonathan,Rodriguez, Fernando,Rozas, Isabel,Meana, J. Javier,Callado, Luis F.
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p. 6009 - 6012
(2008/09/16)
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- A facile synthesis of long chain acyclic alkanols via Kolbe coupling: 1-Docosanol and 1-triacontanol
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A convenient synthesis of long chain acyclic alkanols viz., 1-docosanol and 1-triacontanol has been devised via Kolbe radical coupling of mono-methyl azelate 2, which has been synthesized from azelaic acid 1. The dimer viz. dimethyl thapsate 3, on Ba(OH)2 hydrolysis affords mono-methyl thapsate 4, which upon mixed Kolbe coupling with appropriate alkanoic acid [CH3(CH)2)nCOOH, n = 6 for 1-docosanol and n = 14 for 1-tri-acontanol] gives the cross coupled products methyl docosanoate 7 and methyl triacontanoate 8 along with the radical dimers dimethyl triacontanedioate 4′ and tetradecane 5′/triacontane 6′ as byproducts. Compounds 7 and 8 on LAH reduction in dry THF yield 1-docosanol 9 and 1- triacontanol 10, respectively in high yields. The mixed anodic coupling has been studied by varying parameters viz. degree of neutralization and molar ratio of compounds 4 and C8/C16 alkanoic acid, current density, anode material etc.
- Yadav, Ashok K.,Singh, Arpita
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p. 1724 - 1726
(2007/10/03)
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- Electroorganic synthesis 65. Anodic homocoupling of carboxylic acids derived from fatty acids
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Fatty acid derived carboxylic acids with double bonds, hydroxy-, amino-, keto-, ester- and epoxy groups are anodically coupled to dimers (Kolbe electrolysis) in 29 to 81% yield and up to a 2.5 mol scale. Problems due to the low conductivity of fatty acid salts were overcome by the use of a flow cell with a narrow electrode gap. Fatty acids with branched alkyl chains gave dimers with interesting emulsifying properties. Dimethyl hexadecanedioate, accessible from methyl azelate, could be cyclized and further converted into homomuscone and muscone in a few steps. A commercial mixture of dimeric fatty acids (C36-dicarboxylic acids) has been coupled to give C70-diesters. Acta Chemica Scandinavica 1998. Part 64: Nielsen, M. F., Batanero, B.,.
- Weiper-Idelmann, Andreas,Aus Dem Kahmen, Martin,Schaefer, Hans J.,Gockeln, Marianne
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p. 672 - 682
(2007/10/03)
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- Selective Kolbe Electrolytic Coupling Using Glasslike-Hard Carbon Anodes
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The use of some kinds of glasslike-hard carbons was found to lead to selective synthesis of the corresponding Kolbe coupled products in high yields comparable to the use of a Pt anode in anodic oxidation of some carboxylic acids.
- Ohno, Toshinobu,Fukumoto, Tatsumi,Hirashima, Tsuneaki,Nishiguchi, Ikuzo
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p. 1085 - 1088
(2007/10/02)
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- Bifunctional compounds from reaction of alkoxy hydroperoxides with metal salts
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Alkoxy hydroperoxides, obtained by ozonizing olefins in alcoholic solution, were treated with ferrous sulfate. C-C bond scission and radical formation was followed by dimerization of the radicals formed. Ozonides reacted similarly. Acyclic and cyclic olefins, including a cyclic enol ether, gave rise to a range of α,ω-disubstituted products in modest yields. By using ferric chloride, ω-chloro esters were obtained from the alkoxy hydroperoxides derived from olefinic esters.
- Cardinale,Laan,Van Der Steen,Ward
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p. 6051 - 6054
(2007/10/02)
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