Syntheses of 3-substituted 1-methyl-6-phenylpyrimido[5,4-e]-1,2,4-triazine-5,7(1H,6H)-diones (6-phenyl analogs of toxoflavin) and their 4-oxides, and evaluation of antimicrobial activity of toxoflavins and their analogs

Article abstract of DOI:10.1248/cpb.41.362

6-Phenyl analogs of toxoflavin {1-methyl-6-phenylpyrimido[5,4-e]-1,2,4-triazine-5,7(1H,6H)-diones} (7a-f) and their 4-oxides (8a-f) were synthesized by nitrosative or nitrative cyclization of the aldehyde hydrazones (6a-f) of 6-(1-methylhydrazino)-3-phenyluracil (5). Both sets of compounds, 7a-f and 8a-f, gave the corresponding 1-demethyl derivatives (10a-f) upon treatment with nucleophiles such as dimethylformamide (DMF) and acetic acid under heating. The activities of toxoflavins (1a-e), toxoflavin 4-oxides (3a-e) and their 6-phenyl analogs (7a-f and 8a-f) against a variety of bacterial and fungal strains were examined. Most of the compounds showed strong inhibitory activities against gram-positive bacteria. Among the compounds, 1c, 1d, 1e, and 3c exhibited the strongest inhibitions of Micrococcus lutea (0.5 μg/ml minimal growth-inhibitory concentration) and Staphylococcus aureus 4R (1 μg/ml), as well as Bacillus subtilis and Staphylococcus aureus (1-2 μg/ml). Most of the compounds had strong antifungal activity (2-100 μg/ml minimal growth-inhibitory concentration) against Candida albicans and Saccharomyces cerevisiae.

Full text of DOI:10.1248/cpb.41.362

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