Study of three-component reaction of α-ketoesters and active methylenes with OH-acids to synthesize new 2-amino-4H-pyran derivatives and evaluation of their antibacterial and antioxidant activities

Synthesis of new derivatives of 2-amino-4H-pyrans is reported via three-component reaction of alpha-ketoesters, active methylenes, and OH-acids in the presence of catalytic amount of piperidine at room temperature with high to excellent yields. The structure of synthesized compounds was characterized by FTIR, H-1, C-13 NMR spectroscopy, and mass spectrometry. Simplicity of procedure, mild reaction conditions, short reaction time, and easy separation of the products make this an interesting alternative to other reported approaches. Also, their antibacterial and antioxidant activities were evaluated against Staphylococcus aureus and Bacillus subtilis as Gram-positive bacteria and Escherichia coli and Pseudomonas aeruginosa as Gram-negative bacteria, as well as the radical scavenger DPPH. Among these compounds, 4l including CO2Et substituent and 6-methyl-2H-pyran-2-one moiety showed the highest antioxidant and antibacterial activities. Graphic abstract