LAUSR

Abstract This work describes for the first time a novel functionalization of poly[2,2′-( m -phenylen)-5,5′-bisbenzimidazole] (PBI), a polymer stable in a wide range of solvents, with a DNA base, adenine (PBI-A x% ). Functionalization was achieved through alkylation of N4 benzimidazole nitrogen with 9-(3-bromopropyl) adenine (9-BPA). The N9 adenine nitrogen that binds to deoxyribose in DNA molecule was inhere used for covalent binding to the PBI, leaving free the remaining adenine positions, as the ones available in a natural DNA molecule. Therefore, for the first time, the use of adenine based polymer is here suggested as a biomimicry strategy for degenotoxification of post-reaction synthetic active pharmaceutical ingredient (API) streams. The very same interactions responsible by in vivo genotoxicity, present in the novel adenine based polymer, PBI-A x% , were used for removal of a genotoxic impurity (GTI). Methyl p -toluenesulfonate (MPTS) at 100 ppm in dichloromethane was selected as a representative sulfonate GTI, which is present in a wide range of API post-reaction streams. The functionalization reaction efficiency was assessed using NMR at yields of 40–69% or 27–31%, for addition of 0.13–0.25 or 0.5–1.0 mol eq of 9-BPA to N4 PBI nitrogen, respectively. Synthesis and purification of 9-BPA was first optimized, increasing yields from previously reported values of 38–61%. The maximum removal of genotoxic impurity was obtained for PBI-A 12% polymer, obtained at 0.25 M equivalents of 9-BPA to N4 PBI nitrogen, at a value of (96.6 ± 0.2)%, against (10.2 ± 2.8)% of the original non modified PBI.