The green synthesis of N-hydroxyethyl-substituted 1,2,3,4-tetrahydroquinolines with acidic ionic liquid as catalyst

Abstract

N-Hydroxyethyl-substituted 1,2,3,4-tetrahydroquinolines were synthesized by the reaction of 2-(phenylamino)ethanol with unsaturated ketone catalyzed by acidic ionic liquid N-methyl-2-pyrrolidonium dihydrogen phosphate [NMPH]H2PO4, obviating the need for toxic and expensive catalysts. The acidic ionic liquid not only showed superior performance over H3PO4 but also was stable and could be reused at least five times with a slight loss of activity. It provided a straightforward and efficient protocol for the synthesis of 1,2,3,4-tetrahydroquinoline derivatives.

Keywords

• n-hydroxyethyl substituted 1,2,3,4-tetrahydroquinoline
• ionic liquid
• 2-(phenylamino)ethanol
• unsaturated ketone