A new series from thieno[2,3-d] pyrimidine derivatives have been synthesized based on 2-
(ethylmercapto)-4-mercapto-6-phenyl-5-pyrimidine carbonitrile, these compounds used in the synthesis of
many pyrimidothienopyrimidine derivatives and triazolo[1″,5″:1″,6″]pyrimido[40,50:4,5]thieno[2,3-d] pyrimidine
derivatives. The chemical composition of these compounds was confirmed by 1H NMR, 13C
NMR, and MS techniques. Some of the synthesized compounds were screened for their antimicrobial and
anticancer agent. Compound (9b) showed strong effect on Aspergillus Fumigatus (RCMB 2568), Candida
albicans (RCMB 05036), Saphylococcus aureus (RCMB 010010), Bacillis subtilis (RCMB 010067), Salmonella
sp. (RCMB 010043), and Escherichia coli (RCMB 010052). Compounds (2) and (5a–k) were evaluated
for their IC50 values against two cancer cell lines (MCF-7 and HeLa cells) in the presence of Paclitaxel as
reference material. Compound (5g) showed the highest cytotoxicity against MCF-7 (IC50 values about
18.87 ± 0.2 μg/mL) cells compared with Paclitaxel (IC50 values about 40.37 ± 1.7 μg/mL). Also, compound
(5d) showed the highest cytotoxicity against HeLa (IC50 values about 40.74 ± 1.7 μg/mL) cells compared
with Paclitaxel (IC50 values about 45.78 ± 0.8 μg/mL).