The isolation of cytosine from the hydrolysis of calf thymus tissue in 1894 and its structure determination in 1903, 1 followed by its first synthesis from 2-ethylthiopyrimidin-4 (3H)-one are a few of the first important steps of current nucleotide chemistry. Cytosine derivatives have gained paramount importance in the pharmaceutical sphere, particularly in cases where no vaccination is available and prompt medical treatment is required. Hence these ...