K2CO3-Mediated Synthesis of Functionalised 4-Substituted-2-amino-3-cyano-4H-chromenes via Michael-Cyclization Reactions

Abstract

An efficient approach for the synthesis of functionalized 4-substituted-2-amino-3-cyano-4H-chromenes moderate to high yields (up to 98%) has been achieved via a tandem K2CO3 catalyzed conjugate addition-cyclization reaction of malononitrile and a range of Knoevenagel adducts previously formed from oxindole, pyrazolone, nitromethane, N,N-dimethylbarbituric acid or indanedione. This methodology differs from the previous classical methods in its simplicity and ready availability of the catalyst.

Keywords

• 2-amino-4H-chromenes
• Michael-cyclization
• malononitrile
• K2CO3
• Knoevenagel adducts
• cascade reaction