Synthesis of novel 3-substituted pyridothienopyrimidine derivatives with biological evaluation as antimicrobial agents

Novel 3-substituted pyridothienopyrimidine derivatives have been synthesized via the reaction of 2-{7,9-dimethyl-4-oxopyrido[3′,2′:4,5]thieno[3,2-d]pyrimidin-3(4H)-yl}acetohydrazide(5) with a variety of active reagents and chemicals. Structures of the newly synthesized compounds were established based on spectral data. The resulting pyridothienopyrimidine derivatives were evaluated for their possible antimicrobial activity and some of them represent a new class of potentially antimicrobial compounds, especially compounds 9 and 18 which displayed the highest activity against Gram-positive bacteria, Gram-negative bacteria, and Fungi in MIC range of 0.12―1.95 μg/mL.