Synthesis, characterization, and organocatalytic application of chiral ionic liquids derived from (S,R)-noscapine

ABSTRACT

(S,R)-Noscapine, a phthalideisoquinoline alkaloid has been used as precursor for the synthesis of chiral ionic liquids (CILs). Noscapine based CILs have been synthesized from reaction between (S,R)-noscapine and methyl iodide in acetonitrile at room temperature. The synthesized CILs have been characterized by ¹H NMR, ¹³C NMR, EI-MS, and polarimetry techniques. These CILs have been used as organocatalysts in the enantioselective reduction of prochiral ketones to produce optically active secondary alcohols. The optically active secondary alcohols have been obtained with excellent yields and low to moderate enantiomeric excess (ee); also the complete enantiomeric excess (100% ee) has been achieved in some cases.

GRAPHICAL ABSTRACT

KEYWORDS:

• Asymmetric organocatalysis
• chiral ionic liquids
• enantiomeric excess
• (S,R)-noscapine
• secondary alcohols

Acknowledgment

Authors are highly thankful to the authorities of Sant Longowal Institute of Engineering and Technology, Longowal for providing all the research facilities to perform the research work.