Polyethylene Glycol-Bonded Tetraethyl Ammonium L-Prolinate: A New Highly Efficient Biodegradable Amino Acid-Based Ionic Liquid for the Synthesis of Some DNA Binders as Anticancer Agents

As the research on ionic liquids have advanced, numerous problems have been also reportedincluding poor biodegradability, toxicity (some ionic liquids), unsuitable physicochemicalproperties (large viscosity) and large production costs, which have hindered scaling up ionicliquids for further applications at industrial scale. In order to obtain ‘‘fully green’’ ionic liquids,the starting materials must be at least non-toxic, whilst for a perfect solution and theyshould be renewable. The bio-renewable natural compounds are ideal materials from theviewpoints of both environmental and economic concerns. A few successful samples havebeen reported, for example, using lactates [1] and sugar substitutes [2] to prepare anionic constituentand amino acids [3] to prepare cationic constituent of ionic liquids. Amino acid-basedionic liquids have been shown to have a range of useful properties due to the fact that theycontain two functional groups, a carboxylic acid and amino group, as well as the fact that achiral center is present, which can be obtained relatively inexpensively using naturally derivedamino acids. Further characteristic of amino acid derived ionic liquids includes the improvedbiodegradability. Considering these facts, we herein introduced the polyethylene glycol-bonded tetraethyl ammonium L-prolinate as a new readily biodegradable amino acidbasedionic liquid for the one-pot pseudo-five component synthesis ofbis(pyrazolyl)methanes. Moreover, the anticancer activity of synthesized compounds as novelDNA binding agents was successfully evaluated (Figure 1).