One pot synthesis, antimicrobial and antioxidant activities of fused uracils: pyrimidodiazepines, lumazines, triazolouracil and xanthines

Background: Uracil derivatives have a great attraction because they play an important role in pharmacological activities. Pyrimidodiazepines, lumazines, triazolopyrimidines and xanthines have significant wide spectrum activities including anticancer, antiviral as well as antimicrobial activities.

Results: A newly synthesized compounds pyrimido[4,5-b][1, 4]diazepines 5a-e, 6a-d, lumazines 7a-d, triazolo[4,5-d]pyrimidine 8 and xanthines 9, 10 was prepared in a good yields. The antimicrobial and antioxidant activities of compounds 5a, 5b, 6a, 6d and 8 exhibited a wide range activity against the pathogenic tested microbes (Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, Candida albicans, and Saccharomyces cerevisiae). Compound 8 showed activity against the fungus Aspergillus niger. The highest antioxidant activity was noticed for compound 5a.

Conclusions: A series of novel pyrimido[4,5-b][1, 4]diazepines 5a-e, 6a-d, lumazines 7a-d, triazolo[4,5-d]pyrimidine 8 and xanthines 9, 10 was prepared from 5,6-diamino-1-(2-chlorobenzyl)uracil 3 in good yields. Compounds 5a-e, 6a-d were prepared by sequential manipulation of 3 with α,β-unsaturated ketones. Lumazines 7a-d were obtained from 3 by treatment with phenacyl bromides in the presence of TEA. Compound 8 was prepared by treatment of 3 with HNO₂, while xanthines 9, 10 were obtained from 3 by consecutive acetylation then intramolecular cyclodehydration or heating with malononitrile under solvent-free condition. The antimicrobial and antioxidant activity of this series was evaluated in vitro and they showed either weak or moderate activities. Graphical abstract Several pyrimido[4,5-b][1,4]diazepines, lumazines, triazolo-, and imidazolopyrimidines were synthesized from the starting compound 4,5-diaminouracils. The newly synthesized compounds were screened for both antimicrobial and antioxidant activities.