Synthesis of polyethanolamine dendrons using an improved reduction method

Abstract

This work describes the synthesis of ethanolamine-based dendrons via an improved reduction method using potassium borohydride (KBH4) and Raney nickel (Raney Ni). The synthesis constituted two iterative processes of Michael addition and nitrile reduction. Polyethanolamine dendrons (PEaDron) of up to Generation 2.0 were synthesised under optimised reaction conditions at atmospheric pressure and 40°C, with water as solvent, KBH4:Raney Ni as catalyst at a ratio of 4:1, 1 h of stirring, and direct slow heating during isolation. The core remained as hydroxyl, whereas the amine group grew divergently. System efficacy was confirmed and fully characterised by IR, NMR, and MALDI-TOF spectroscopy analyses. The PEaDron featured a convenient centre for various reactions while the improved reduction method has the potential for the reduction of other nitrile compounds.