نتایج جستجو برای: polyethers

تعداد نتایج: 219  

Journal: :Journal of biomedical materials research 1996
B J Pol P B van Wachem L van der Does A Bantjes

As reported in Part I ("In vivo testing of crosslinked polyethers. I. Tissue reactions and biodegradation," J. Biomed. Mater. Res., this issue, pp. 307-320), microscopical evaluation after implantation of crosslinked (co)polyethers in rats showed differences in the rate of biodegradation, depending on the presence of tertiary hydrogen atoms in the main chain and the hydrophilicity of the polyet...

Journal: :Chemical Society reviews 2009
Christopher J Morten Jeffery A Byers Aaron R Van Dyke Ivan Vilotijevic Timothy F Jamison

This tutorial review traces the development of endo-regioselective epoxide-opening reactions in water. Templated, water-promoted epoxide-opening cyclization reactions can offer rapid access to subunits of the ladder polyethers, a fascinating and complex family of natural products. This review may be of interest to those curious about the ladder polyethers and their hypothesized biogenesis, abou...

Journal: :Journal of biomedical materials research 1996
B J Pol P B van Wachem M J van Luyn L van der Does A Bantjes

The in vivo biocompatibility and biodegradation of cross-linked (co)polyethers with and without tertiary hydrogen atoms in the main chain and differing in hydrophilicity were studied by means of subcutaneous implantation in rats. After 4 days, 1 month, and 3 months postimplantation, the tissue reactions and interactions were evaluated by light microscopy (LM) and transmission electron microscop...

2010
Ivan Vilotijevic Timothy F. Jamison

The proposed biosynthetic pathways to ladder polyethers of polyketide origin and oxasqualenoids of terpenoid origin share a dramatic epoxide-opening cascade as a key step. Polycyclic structures generated in these biosynthetic pathways display biological effects ranging from potentially therapeutic properties to extreme lethality. Much of the structural complexity of ladder polyether and oxasqua...

Journal: :Journal of Synthetic Organic Chemistry, Japan 1971

2011
Charles E. Carraher Michael R. Roner Kimberly Shahi Girish Barot

The ability to inhibit cancer is inherent in organotin materials yet the structural relationships that regulate/direct this activity remains unknown. We measured antitumor activity using a matched pair of cell lines MDA-MB-231 cells that are estrogen-independent, estrogen receptor negative and MCF-7 cells, a cell line that is estrogen receptor (ER) positive. Those polyethers that contained a O-...

Journal: :Journal of the American Chemical Society 2006
Zhifeng Jia Hao Chen Xinyuan Zhu Deyue Yan

A new type of materials, the backbone-thermoresponsive hyperbranched polyether, was successfully synthesized by proton-transfer polymerization of 1,4-butanediol diglycidyl ether and various triols, and the lower critical solution temperature (LCST) values can be readily adjusted from 19.0 to 40.3 degrees C by changing the hydrophilic/hydrophobic balance of BDE and triols.

Journal: :Polymer Chemistry 2021

Different regioisomeric and diastereomeric isosorbide mono-epoxides are prepared polymerized to thermally stable relatively rigid biobased linear polyethers.

2009
Charles E. Carraher Michael R. Roner

Organotin polyethers are easily synthesized employing interfacial polymerization systems involving the reaction of hydroxyl-containing Lewis bases and organotin halides. A wide variety of organotin-containing polymeric products have been synthesized including those derived from natural and synthetic polymers such as lignin, xylan, cellulose, dextran, and poly(vinyl alcohol). Others have been sy...

2012

Crystalline complexes of some alkali and alkaline earth Perchlorates and picrates with macrocyclic polyethers have been synthesized. With the alkyl substituted aromatic macrocyclic polyethers bis(3,5-di-£er£-butylbenzo)-18-crown-6 and bis(4-hexadecylbenzo)-18crown-6 it was not possible to isolate all the complexes in the crystalline form. In fact the steric hindrance, caused by the alkyl substi...

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