5-Fluoro-2-deoxycytidine is a fluorinated pyrimidine analog antimetabolite with potential antineoplastic activity. As a prodrug, 5-fluoro-2-deoxycytidine is converted by intracellular deaminases to the cytotoxic agent 5-fluorouracil (5-FU). 5-FU is subsequently metabolized to active metabolites including 5-fluoro-2-deoxyuridine monophosphate (FdUMP) and 5-fluorouridine triphosphate (FUTP). FdUMP binds to and inhibits thymidylate synthase, thereby reducing the production of thymidine monophosphate, which leads to depletion of thymidine triphosphate and the inhibition of DNA synthesis and cell division. FUTP competes with uridine triphosphate (UTP) for incorporation into the RNA strand, which results in the inhibition of RNA and protein synthesis and cell proliferation. 5-Fluoro-2-deoxycytidine undergoing trials to test its effectiveness in treating cancer that has not responded to standard therapies.

2′-Deoxycytidine (deoxyC) is one of the deoxy nucleosides, which after phosphorylation to dCTP is used to synthesize DNA via various DNA polymerases or reverse transcriptases. Deoxycytidine is phosphorylated by deoxycytidine kinase (dCK). This enzyme catalyzes the initial conversion of the nucleosides deoxyadenosine (dA), deoxyguanosine (dG), and deoxycytidine (dC) into their monophosphate forms, with subsequent phosphorylation to the triphosphate forms performed by additional enzymes.

2′-Deoxycytidine (deoxyC) is one of the deoxy nucleosides, which after phosphorylation to dCTP is used to synthesize DNA via various DNA polymerases or reverse transcriptases. Deoxycytidine is phosphorylated by deoxycytidine kinase (dCK). This enzyme catalyzes the initial conversion of the nucleosides deoxyadenosine (dA), deoxyguanosine (dG), and deoxycytidine (dC) into their monophosphate forms, with subsequent phosphorylation to the triphosphate forms performed by additional enzymes.