Green synthesis of N-heterocyclic compounds using Diels-Alder reactions with electron deficient acetylenic compounds

The reaction between activated acetylenic compounds, OH-acids and dimethyl acetylenedicarboxylate in Et3N at room temperature leads to pyran derivatives in good yields. The present protocol offers the advantages of clean reaction, short reaction time, high yield, easy purification and affordability of the catalyst. The antimicrobial activity of some synthesized compounds was studied employing the disk diffusion test on Gram-positive bacteria and Gram-negative bacteria. The results of disk diffusion test showed that these compounds prevented the bacterial growth