Purine formation requires tautomerization of 5 to the conjugated amidine 6 (via hydrogen-tunneling, thermally with H+ -catalysis, or by photolysis) or to keteneimine 7 (by photolysis).

Vitamin B9, crucial for cell division and DNA synthesis, is vital during pregnancy and infancy to prevent birth defects. Folate-rich foods like leafy greens, legumes, citrus fruits, and fortified ...