5617-32-3Relevant 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.
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.
Molecular motion in crown ethers. Application of 13C and 2H NMR to the study of 4-carboxybenzo-24-crown-8 ether and its KNCS complex in solution and in the solid phase
Buchanan,Moghimi,Ratcliffe
, p. 1437 - 1446 (2007/10/03)
Large-amplitude solid phase molecular motion has been detected in the macrocyclic ring of the title crown either via 13C CPMAS NMR. To study the details of the dynamic processes, two selectively deuterated d4 derivatives have been prepared and examined via 2H NMR as a function of temperature. A phase change occurring around 277 K has been verified by differential scanning calorimetry (DSC) and a model for the motional processes has been developed involving equivalent two-site flips of the CD2 groups. The amplitude of the CD2 motions apparently decreases the closer the group is to the aromatic ring. The influence of KNCS complexation on the 13C CPMAS spectrum and on 13C spin lattice relaxation times in solution has been explored.