19576-38-6Relevant articles and documents
Beyond PEG2000: Synthesis and functionalisation of monodisperse pegylated homostars and clickable bivalent polyethyleneglycols
Szekely, Gyoergy,Schaepertoens, Marc,Gaffney, Piers R.J.,Livingston, Andrew G.
supporting information, p. 10038 - 10051 (2014/08/18)
A new strategy to access highly monodisperse, heterobifunctional linear polyethylenglycols (PEGs) has been designed. This was built around unidirectional, iterative chain extension of a 3-arm PEG homostar. A mono-(4,4′-dimethoxytriphenylmethyl) octagol building block, DmtrO-EG 8-OH, was constructed from tetragol. After six rounds of chain extension, the monodisperse homostar reached the unprecedented length of 56 monomers per arm (PEG2500). The unique architecture of the synthetic platform greatly assisted in facilitating and monitoring reaction completion, overcoming kinetic limitations, chromatographic purification of intermediates, and analytical assays. After chain terminal derivatisation, mild hydrogenolytic cleavage of the homostar hub provided heterobifunctional linear EG56 chains with a hydroxyl at one end, and either a toluene sulfonate, or a tert-butyl carboxylate ester at the other. A range of heterobifunctional, monodisperse PEGs was then prepared having useful cross-linking functionalities (-OH, -COOH, -NH2, -N3) at both ends. A rapid preparation of polydisperse PEG homostars, free of multiply cross-linked chains, is also described. The above approach should be extendable to other high value oligomers and polymers.
METHOD FOR THE SYNTHESIS OF INITIATORS FOR TELECHELIC POLYISOBUTYLENES
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Page/Page column 15-16, (2012/07/27)
A new methodology for the synthesis of a novel difunctional- and a known trifunctional initiator, i.e., 1,3-di(2-methoxy-2-propyl)-5-isopropyl benzene and 1,3,5-tri(2-methoxy-2-propyl) benzene, respectively, for the preparation of di- and tri-telechelic polyisobutylenes. The synthesis proceeds in three steps: 1) catalytic peroxidation of 1,3,5-triisopropylbenzene, 2) reduction of the peroxides to the corresponding alcohols, and 3) methylation of the alcohols. By controlling the conversion of the key peroxidation step the relative ratio of di- and tri-fiinctional intermediates can be controlled. By the use of the 1,3-di(2-methoxy-2-propyl)-5-isopropyl-benzene, well-defined di-methoxy telechelic polyisobutylenes can be synthesized. Although the overall combined yield of the two initiators was only 14-20%, because of the low cost of the starting material, reagents used, and simple manipulations these compounds represent the most cost effective initiators to-date for the preparation of telechelic polyisobutylenes.
Cobalt-catalyzed cyclotrimerization of alkynes in aqueous solution [10]
Sigman,Fatland,Eaton
, p. 5130 - 5131 (2007/10/03)
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