Background: 1, 3, 4-thiadiazoles, 1, 3, 4-thiadiazines and thienopyrimidines have newly attracted
attention due to their forceful pharmacological activities. They showed antimicrobial, antiviral, analgesic and
Objective: The aim of this research is to synthesize new thiadiazolothienopyrimidines (2-10), thienopyrimidothiadiazines
(11-15), quinoxaline-thienopyrimidinones (16) and thienopyrimido- thiadiazinoquinoxalinones
(17) via effectual high yield procedure for assessing their antimicrobial activity.
Method: A series of new 1, 3, 4-thiadiazolothienopyrimidines, thienopyrimidothiadiazines and thienopyrimidothiadiazinoquinoxalinones
was prepared from 6-acetyl-3-amino-5-methyl-2-thioxo-2, 3-dihydrothieno [2, 3-d]
pyrimidin-4(1H)-one (1) as the beginning material.
Results: The 1, 3, 4-thiadiazoles, 1, 3, 4-thiadiazines derivatives (1-17) were synthesized in adequate to good
yields (60-85%) in a stepwise effectual procedure under condition. The chemical structures of these new compounds
were confirmed via many spectroscopic techniques as UV, IR, NMR, mass spectra and elemental
analysis. In vitro, antimicrobial was evaluated for the synthesized compounds using minimal inhibitory concentration
of these compounds against bacteria and fungi.
Conclusion: The 1, 3, 4-thiadiazole and 1, 3, 4-thiadiazine derivatives (15-17) exhibited higher antimicrobial
activity (Gram-positive, Gram-negative bacteria and fungi) compared with the standard antibiotic drugs;
Levofloxacin (Tavanic) and Nystatin.