Nitrogen containing heterocycles have a quintessential role in synthetic chemistry, cell biology and are part of enormous natural products. Compounds of these classes playing a cardinal role are the six-membered unsaturated rings having nitrogen referred as azines. Similar analogues with two ring nitrogen are termed as diazines. The diazines exist in three isomeric forms depending on the position of the nitrogen, pyridazine (1, 2-diazine), pyrimidine (1, 3-diazine), and pyrazine (1, 4-diazine) (Figure 1). Pyrimidines have remarkable biotic relevance and are the omnipresent isomer among the diazines (