Synthesis and characterization of carborane-functionalized hyperbranched polyester for boron neutron capture therapy

Authors : Gülten ÖZÇAYAN, Yüksel ŞAHİN, A Ernur SÖYLEMEZ, M Elif ÜNSAL

Pages : 252-262

Doi:10.30728/boron.763317

View : 32 | Download : 12

Publication Date : 2021-03-31

Article Type : Research Paper

Abstract :The purpose of this study is to synthesize new boron containing carrier compound  for Boron Neutron Capture Therapy (BNCT) which is two-component radiation  therapy method that especially is promising for the treatment of brain tumors and  is being actively researched in many countries. For this research hyperbranched  polyester (HBP), bifunctional p-carborane and carborane-functionalized HBP  were synthesized. Dipentaerythritol was chosen as a core molecule of the HBP  and esterified with dimethylol propionic acid. Observed characteristic ester bands  and OH stretching band in the FTIR spectrum and the methyl & methylene peaks  in the 1H NMR spectrum of HBP indicated that hyperbranched polyester synthesis  was done successfully. A bifunctionalized p-carborane containing an acid group  and a benzyl ether protected alcohol was prepared in three-step reactions. As a  result of these reactions, a bifunctionalized p-carborane compound was produced  with 60% yield. Then, the HBP was esterified with the bifunctional p-carborane.  The characterization of the synthesized compounds was determined by FTIR and  NMR spectra. The synthesis of carborane-functionalized HBP was confirmed by  disappearance of HBP's OH groups and B-H stretching band observed in the  FTIR spectrum of carborane-functionalized HBP and in addition, appearance of  proton signals of HBP core, carborane linker and peripheral-protecting groups in  the 1H-NMR spectrum. Finally, synthesized water-soluble carborane-containing  HB carrying many boron atoms should be served as potential BNCT agents.
Keywords : Bnct, boron, carborane, esterification, hyperbranced polyester