Green one-pot synthesis and in vitro antibacterial screening of pyrano[2,3-c]pyrazoles, 4H-chromenes and pyrazolo[1,5-a]pyrimidines using biocatalyzed pepsin

In recent years, there has been a lot of interest in the modern organic synthesis using enzymes as biocatalysts. A multicomponent reaction of 4-formylphenyl benzoates, malononitrile, and pyrazolones utilizing pepsin as a biocatalyst was investigated in different reaction conditions. The best yields of pyrano[2,3-c]pyrazoles were obtained by grinding the respective reactants in a mortar in the presence of pepsin for 1.5-2 h at room temperature. Instead of pyrazolones, 1,3-cyclic diketones and 4-arylazo-5-aminopyrazoles were used to prepare new series of 4H-chromenes, and pyrazolo[1,5-a]pyrimidines in good to excellent yields after grinding the respective reactants for 0.5-3 h. The new target molecules showed a wide range of antibacterial activity against four different ATCC bacterial strains. The pyrazolo[1,5-a]pyrimidines 14a and 14f displayed moderate antibacterial activity against the K. pneumoniae and S. aureus strains with inhabitation zones of 29.6-30.3 mm and MIC values of 125-250 mu g/mL.

Automated summary

In recent years, there has been growing interest in the use of enzymes as biocatalysts for modern organic synthesis. This study investigated the synthesis of various compounds using pepsin as a biocatalyst. The results showed that by adjusting the reaction conditions, different compounds could be synthesized with good yields, and these compounds exhibited a wide range of antibacterial activity.