5-Azacytosine serves as a crucial reactant in several synthetic pathways. It is utilized in the enzymatic synthesis of nucleoside analogs employing immobilized 2′-deoxyribosyltransferase from Lactobacillus reuteri. Additionally, it participates in reactions involving oxide radical ions. Furthermore, 5-Azacytosine exhibits potential as an antitumor and antiproliferative agent against human leukemia cells. Its versatility and reactivity make it a valuable compound in both enzymatic and radical-mediated synthetic processes, as well as in the development of potential therapeutic agents against leukemia.