The synthesis of 2-amino-4H-chromenes using L-proline as a catalyst

2-Amino-4H-pyrans are an important class of heterocyclic compounds having important biological activities. During the last decade, such compounds had shown interesting pharmacological properties including antimicrobial, antiviral, mutagenicity, antiproliferative, sex pheromone, antitumor, cancer therapy, and central nervous system activity [1]. Multi-component reactions (MCRs) constitute an especially attractive synthetic strategy for rapid and efficient library generation due to the fact that the diversity can be achieved simply by varying the reacting components [2]. A mixture of resorcinol, malononitrile, aldehyde, and L-proline in ethanol were stirred. After completion of the reaction (monitored by TLC, ethyl acetate/n-hexane 1:1), the solvent was evaporated under reduced pressure, water and ethanol were added to the reaction mixture, and the resulting solid was separated by filtration. The resulting chromenes were charctersized IR and 1H-NMR.