Synthesis, Characterization, and Antimicrobial Activity of New Thienopyrimidine Derivatives

Nowadays heterocyclic compounds containing pyrimidine scaffold attract the interest of many organic chemists due to their strong biological activity, so herein we present the synthesis of new polycyclic compounds starting from 4-chloro-9-phenyl-N-(p-tolyl)pyrimido[5',4':4,5]thieno[3,2-d][1,2,3]triazin-7-amine (1) which allowed to react with hydrazine hydrate to give hydrazinyl triazine compound (2) which subjected to some ring closure reactions using various reagents represented in triethyl orthoformate, acetyl acetone, and carbon disulfide to give compounds (3–5), respectively. Also, when the hydrazinyl compound was allowed to react with acetophenone, ethoxymethylene ethylcyano acetate, and diethyl malonate gave the derivatives (9–11), respectively. The structures of all newly synthesized compounds were confirmed using spectral analysis techniques as well as elemental analysis. Besides, four new compounds were screened for their antimicrobial activity using different strains of bacteria and fungi, and compound 5 displayed the best antimicrobial activity among all the tested compounds.