3386-18-3Relevant articles and documents
Highly efficient synthesis of monodisperse poly(ethylene glycols) and derivatives through macrocyclization of oligo(ethylene glycols)
Zhang, Hua,Li, Xuefei,Shi, Qiuyan,Li, Yu,Xia, Guiquan,Chen, Long,Yang, Zhigang,Jiang, Zhong-Xing
, p. 3763 - 3767 (2015/03/18)
A macrocyclic sulfate (MCS)-based approach to monodisperse poly(ethylene glycols) (M-PEGs) and their monofunctionalized derivatives has been developed. Macrocyclization of oligo(ethylene glycols) (OEGs) provides MCS (up to a 62-membered macrocycle) as versatile precursors for a range of monofunctionalized M-PEGs. Through iterative nucleophilic ring-opening reactions of MCS without performing group protection and activation, a series of M-PEGs, including the unprecedented 64-mer (2850Da), can be readily prepared. Synthetic simplicity coupled with versatility of this new strategy may pave the way for broader applications of M-PEGs. Macrocycles make synthesis easier: Convenient macrocyclization of the OEGs provides versatile macrocyclic sulfates. These compounds are cornerstones for both monofunctionalization of OEGs and highly efficient synthesis of monodisperse PEGs and derivatives, including an unprecedented 64-mer.
Synthesis of oligo(ethylene glycol) toward 44-mer
Ahmed, Saleh A.,Tanaka, Mutsuo
, p. 9884 - 9886 (2007/10/03)
A synthetic method for oligo(ethylene glycol) toward 44-mer (FW = 1956.35) is described. Reiteration of Williamson's ether synthesis and hydrogenation to remove protecting benzyl group affords desired oligo(ethylene glycol) toward 44-mer in moderate yields. The advantages in this method are use of commercially easily available materials as starting materials and procedures avoiding difficulty in purification of the products as much as possible.
Multigram Synthesis of Well-Defined Extended Bifunctional Polyethylene Glycol (PEG) Chains
Loiseau, Francois A.,Hii, King Kuok,Hill, Alison M.
, p. 639 - 647 (2007/10/03)
A series of novel, well-defined, unsymmetrical poly(ethylene glycol) chains of the type X(OCH2-CH2)nY (where X = protecting group; Y = nucleofuge or a different protecting group; n = 3, 6, 9, 12, 15, 18, and 24) were prepared in high yields by applying orthogonal protecting groups. The purity of the compounds was fully verified by elemental and high-resolution mass spectrometry analyses.
An expedient synthesis of monodispersed oligo(ethylene glycols)
Burkett, Brendan A.,Chan, Tak Hang
, p. 1007 - 1010 (2007/10/03)
A convenient approach to the synthesis of oligo(ethylene glycols) under phase transfer conditions is described. Oligo(ethylene glycols) (x = 7-12) are obtained in excellent yields and high purity via modular, bi-directional elongation of readily available ethylene glycol bis-tosylates.
Synthesis and analysis of polyethylene glycol linked P-glycoprotein-specific homodimers based on (-)-stipiamide
Andrus, Merritt B.,Turner, Timothy M.,Updegraff, Emily P.,Sauna, Zuben E.,Ambudkar, Suresh V.
, p. 3819 - 3822 (2007/10/03)
A series of five homodimeric polyethylene glycol (PEG) linked homodimers based on the multidrug resistance reversal agent (-)-stipiamide were made and tested for their ability to interact with P-glycoprotein, the protein responsible for multidrug resistance, using ATPase and photoaffinity displacement assays. Key reactions include a new alkoxide-mesylate displacement for the assembly of the PEG linkers and a double Sonogashira coupling reaction.
Preparation and crystallinity of a large unsubstituted crown ether, cyclic heptacosa(oxyethylene) (cyclo-E27, 81-crown-27), studied by Raman spectroscopy, X-ray scattering and differential scanning calorimetry
Yang, Zhuo,Yu, Ga-Er,Cooke, Jennifer,Ali-Adib, Ziad,Viras, Kyriakos,Matsuura, Hiroatsu,Ryan, Anthony J.,Booth, Colin
, p. 3173 - 3182 (2007/10/03)
Cyclic heptacosa(oxyethyelene) (cyclo-E27, 81-crown-27) was prepared from linear α-hydro, ω-hydroxy-heptacosa(oxyethylene) by reaction with tosyl chloride under alkaline conditions, purified by preparative-scale gel permeation chromatography, and studied by laser-Raman spectroscopy, wide-angle and small-angle X-ray scattering, and differential scanning calorimetry. Comparison was made with the properties of linear oligo(oxyethylene) dimethyl ethers (including C1E27C1). The sub-cell of the crystalline cyclic oligomer was the same as that of its linear counterparts, i.e. the same as that of high-molar-mass poly(oxyethylene). However, the cyclic oligomer crystallised as a twice-folded ring, as confirmed by its long spacing and the frequency of its single-node longitudinal acoustic mode (LAM-1). Enthalpies of fusion and melting temperatures were analysed to provide estimates of the enthalpy and entropy of formation of a fold in an oligo(oxyethylene) layer crystal.
TEMPLATE EFFECTS. 7. LARGE UNSUBSTITUTED CROWN ETHERS FROM POLYETHYLENE GLYCOLS: FORMATION, ANALYSIS, AND PURIFICATION
Vitali, Chiara Antonini,Masci, Bernardo
, p. 2201 - 2212 (2007/10/02)
Through the reaction of polyethylene glycols with tosyl chloride and heterogeneous KOH in dioxane not only coronands from crown-4 to crown-8 can be obtained but also larger homologues.A systematic investigation has shown that: i) crown-9 and crown-10 can be formed from nona- and deca-ethylene glycol, respectively, and isolated in pure form; ii) the whole series of polyethylene glycols from tri- to deca-ethylene glycol yields not only the corresponding crown ethers but also higher cyclooligomers that can be analyzed up to about crown-20 by glc: in particular crown-12 and crown-16 were obtained from tetraethylene glycol and purified by column chromatography on cellulose; iii) the reaction, as applied to commercial mixtures of polyethylene glycols (from PEG 200 to PEG 1000), gives fairly high yields of crown ethers also in the region of large ring sizes.The contribution of the template effect of K(+) ion and the cyclooligomerization reactions for the various ring sizes are discussed.
Intramolecular End-to-End Reactions of Photoactive Terminal Groups Linked by Poly(oxyethylene) Chains
Ashikaga, Kazuo,Ito, Shinzaburo,Yamamoto, Masahide,Nishijima, Yasunori
, p. 2443 - 2450 (2007/10/02)
The triplet-sensitized photochemical reaction using a series of poly(oxyethylene) chains with a pair of photoactive terminal groups, dibenzazepine (DBA) chromophores (DBA-COCH2CH2(OCH2CH2)nOCH2CH2CO-DBA, n=0-10) was examined.The photoirradiation of bichromophoric compounds caused either intra- or intermolecular reactions.These reactions were kinetically analyzed by two different methods: the measurement of deactivation processes of the reaction intermediates (excited triplet state of DBA) by nanosecond laser photolysis and the quantitative analysis of the reaction products by GPC.The intramolecular deactivation rate constant, kintra, showed a remarkable chain-length dependence; the maximum kintra value appeared at n=5 and it was found to be 5.9X104 s-1.On the other hand, the intramolecular cyclization rate also depends on the chain length; the maximum quantum yield, φintrad, was given at n=7 (φintrad=0.51).The chain length for the maximum cyclization yield shifted slightly to the longer region than that for the maximum kintra value due to the restriction of the terminal structure (anti-configuration).The results obtained for this reaction system are compared with those obtained for the previously reported polymethylene system and the effect of chain flexibility on the intramolecular ring-closure reaction is discussed.
A NOVEL, UNEQUIVOCAL SYNTHESIS OF POLYETHYLENE GLYCOLS
Coudert, Gerard,Mpassi, Michel,Guillaumet, Gerald,Selve, Claude
, p. 19 - 26 (2007/10/02)
Unequivocal synthesis of polyethyleneglycols is presented.The key step for this synthesis is the selective monobenzylation of oligoethyleneglycols by the phase transfer catalysis technique.
