Solvent-Free Synthesis of New Bis(Benzimidazole-2-Alkylthio) Polyethylene Oxides Starting from Dithiols

Polyethylene oxide (PEO) could be incorporated in molecular structure by several ways. A series of diacid S-alkylpolyethylene oxides 4a-i have been prepared from dithiols 1a-c through multistep reaction sequence. Novel symmetric bis-benzimidazoles (polyethylene oxide) 6a-i have been synthesized over green route. The condensation of the title compounds 4a-i on o-phenylenediamine 5, via the further deamination reaction and without catalyst, afforded the corresponding bis-benzimidazoles 6a-i in acceptable yields. The new compounds were established on the basis of their elemental analysis, IR, 1H NMR, 13C NMR and mass spectral data.