Microwave assisted synthesis of 4-aza-flavone/flavanone compounds, N-alkyl derivatives, catalytic hydrogenation reactions and biological activities

In this study first of all, hydroxy substituted azachalcones (1-2) which are analogs of the natural occurring chalcones were synthesized. At the second step, azaflavone/azaflavanone (3-4) which are analogs of natural flavone/flavanone were yielded from compounds 1-2 by microwave assisted method and their N-alkyl derivatives (5-26) were synthesized. Then, compounds 27-32 were obtained with the catalytic hydrogenation reactions of the synthesized aza-flavone/flavanone using different catalyst, temperature and pressure. According to the literature research, compounds 1-3 and 10 were found to be known but, it was seen that there was no study about compounds 4-9, 11-32. Identification of compounds was done by spectroscopic methods using NMR (1H NMR, 13C NMR, APT, COSY), FT-IR, UV, LC-MS/MS techniques. Antimicrobial activity of compounds 1-32 were determined by measuring MIC values. According to antimicrobial results, compounds 1-4 were effective with all microorganisms in high concentrations. But alkyl compounds 4-25, especially with 9-15 carbon chained derivatives of compound 3 and 4 showed high antimicrobial activities against Gram-positive bacteria with the increasing length of the chain. The antioxidant activity results of identified compounds showed that compounds 27-32 had more active and the activity of alkyl derivatives decreased with the chain contraction generally. The SC50 values increased with the chain contraction. It was seen that there was a concord between DPPH scavenging activity and FRAP test results.