Chromone-fused cytosine analogues: synthesis, biological activity, and structure-activity relationship.

The preparation of a series of novel chromone-fused cytosine analogues, i.e., chromeno[2,3-d]pyrimidines has been carried out from substituted 2-amino-4-oxo-4H-chromene-3-carbonitriles with urea, thiourea, and guanidine under different reaction conditions. These chromone-fused cytosine analogues were evaluated for their in vitro activity against Mycobacterium tuberculosis H37Rv strain and different microbial pathogenic strains in cell culture for their structure-activity relationships, respectively. Among the synthesized compounds, 2d, 3a, and 4e showed better results against Mycobacterium tuberculosis H37Rv. The compounds 2a, 2b, and 3a showed potential antibacterial activity against E. coli and P. aeruginosa, while the majority of compounds were found to be active against S. aureus as compared to ampicillin. The synthesized cytosine analogues having an imine (-C&dbnd;NH) have been less sensitive to the bacterial and fungal strains but have a more beneficial effect on Mycobacterium tuberculosis H37Rv.

Design, synthesis and in vitro evaluation of antitubercular and antimicrobial activity of some novel pyranopyrimidines.

The clinical significance of pyran and pyrimidine condensed systems and the raise in problem of multidrug resistant bacterial pathogens has directed us to synthesize pyranopyrimidine derivatives via the reactions of the versatile, 2-amino-4-(4-methoxyphenyl)-4H-substituted chromene-3-carbonitrile with the appropriate reagents. The newly synthesized compounds were characterized by IR, (1)H NMR, (13)C NMR, Mass spectra and Elemental analysis. The compounds were evaluated for their in vitro antitubercular activity against Mycobacterium tuberculosis H(37)Rv [ATCC-27294] and antibacterial activity against Staphylococcus aureus [ATCC-25923] and Streptococcus pyogenes [MTCC-443] as gram-positive, Escherichia coli [ATCC-25922] and Pseudomonas aeruginosa [MTCC-441] as gram-negative bacterial strains and antifungal activity against Aspergillus niger [MTCC-282]. Several derivatives exhibited pronounced antitubercular and antimicrobial activities.