“…Examples of drugs with a pyrimidine nucleus are antibacterial and antimalarial agents targeting the folate pathway: trimethoprim, iclaprim, sulfadimethoxine, pyrimethamine, and sulfadoxine; antimetabolite and ergosterol biosynthesis inhibitor antifungal drugs: flucytosine and voriconazole; antimetabolite anti-cancer agents: 5-fluorouracil and capecitabine; tyrosine kinase inhibitors: imatinib, dasatinib, and nilotinib; antivirals: ara-c, idoxuridine, zidovudine, stavudine, lamivudine, and emtricitabine; and the antitubercular drug capreomycin (Figure 1). Many substituted pyrazine derivatives were reported with potential antibacterial [6][7][8][9][10][11], antifungal [12][13][14][15], anticancer [16][17][18][19][20][21], antioxidant [22][23][24][25], and antitubercular [9,[26][27][28] activities. Similarly, pyrimidine-based compounds also showed excellent antimicrobial (antibacterial and antifungal) [29][30][31][32][33], antimycobacterial [34][35][36][37][38], antioxidant [39][40][41][42], cytotoxic and anticancer [42][43][44]…”