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

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

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