Thymidine, also known as 5-methyluracil, was first isolated from calf thymus and given this name. It is the main pyrimidine component in deoxyribonucleic acid. Through glycosidic chain connection with deoxyribose, deoxythymidine is formed, and its triphosphate compound is deoxythymidine triphosphate, which is a precursor of thymine in the biosynthesis process of deoxyribonucleic acid.
