The oxazole and pyrimidine rings are widely displayed in natural products and synthetic molecules. They are known as the prime skeletons for drug discovery. On the account of structural and chemical diversity, oxazole and pyrimidine-based molecules, as central scaffolds, not only provide different types of interactions with various receptors and enzymes, showing broad biological activities, but also oc-How to cite this article:

Five imidazo[1,2-c]pyrimidine and pyrimido[1,6-a]pyrimidine derivatives were designed, synthesized and evaluated for their antiproliferative activity and cytotoxicity. Primary bioassays in vitro showed that two of five synthesized compounds, 6-benzyl-8-(methylsulfonyl)-2,6-dihydroimidazo[1,2-c]pyrimidin-5(3H)-one, and 9-(methylsulfonyl)-7propyl-2,3,4,7-tetrahydro-6H-pyrimido[1,6-a]pyrimidin-6-one possessed potent antiviral activity against BKV (EC50: 0.66 μM and 0.96, respectively). The selectivity index of these compounds is similar to that of cidofovir. Although antiviral activity was evident in secondary assays, significant virus inhibition occurred at or near the cytotoxic concentration (SI90=1). Here we show that substituted pyrimidine derivatives are a promising structure class of chemical compounds for the development of antiviral drugs against BKV infections. Hence these compounds may be taken as lead compounds for further development of novel antimicrobial and anticancer agents.

Anticancer activity of a series of polyfunctional substituted 1,3-thiazoles has been studied within the international scientific program “NCI-60 Human Tumor Cell Lines Screen”. Screening was performed in vitro on 60 cell lines of lungs, kidneys, CNS, ovaries, prostate, and breast cancer, epithelial cancer, leukemia, and melanoma. The most effective compounds were those with a piperazine substituent at C2 of the 1,3-thiazole cycle: 1-(4-((4-methylphenyl)-sulfonyl)-2-phenyl-1,3-thiazol-5-yl)piperazine (average lg GI50 = -5.87, lg TGI = -5.54, lg LC50 = -5.21), 1-(2-(3,5-dimethyl-1H-pyrazol-1-yl)-4-((4-methylpheyl)sulfonyl)-1,3-thiazol-5-yl)piperazine (average lg GI50 = -5.66, lg TGI = -5.26, lg LC50 = -4.83), and 1-(2,4-bis((4-methylphenyl)sulfonyl)-1,3-thiazol-5-yl)piperazine (average lg GI50 = -5.67, lg TGI = -5.21, lg LC5050 = -4.67).