Abstract
Recently, ionic liquids (ILs) have been regarded as ideal media for non-aqueous bio-catalysis. In this work, the synthesis of warfarin by the lipase-catalyzed Michael addition in IL media and the parameters that affected the warfarin yield were investigated. Experimental results demonstrated that the chemical structures of the ILs were a major factor for influencing the warfarin yield. The ILs containing the NTf2– anion were suitable reaction media due to the high chemical stability of this anion. The incorporation of the hydroxyl group on the IL cation significantly improved the lipase activity due to the H2O-mimicking property of this group. The lipase activity decreased by increasing the alkyl chain length on the IL cation due to the non-polar domain formation of the IL cation at the active site entrance of lipase. The ILs and lipase could be reused no less than five times without reduction in the warfarin yield.
Highlights
In recent decades, enzymes have been regarded as green catalysts because they are recyclable non-toxic materials and the enzymatic reactions are usually performed under mild conditions [1,2].Lipases are the most used enzymes because of their high stability, activity, wide range of substrates, and low cost [3,4,5,6]
It has been reported that the nucleophilicity of anions increases in the following trend: PF6 – < BF4
The Fourier Transform Infrared (FT-IR) spectra of lipase before and after use were measured and the results shown in Figure 6 indicate that the FT-IR spectrum of the recovered lipase is identical to that of the fresh one, which suggests that lipase remains its native conformation after reaction
Summary
Lipases are the most used enzymes because of their high stability, activity, wide range of substrates, and low cost [3,4,5,6]. They can catalyze many reactions such as the Michael addition [3,4,5], esterification [6], ester-hydrolysis [7], and transesterification [8]. Among these reactions, Michael addition is one of the most effective ways to form mild C–C bonds and generate interesting, drug-like scaffolds.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
