Crystal and molecular structure of 5-trifluorothymine, a metabolite from human urine: Role of fluorine in stacking and hydrogen bonded interactions

5-Trifluorothymine [5F3T] is a metabolite found in human urine. It could also be synthesized by cyclizing the ureidoamides to 5-trifluoromethyl-5,6-dihydrouracil by reflexing in hydrochloric acid. The crystal structure of 5F3T reveals an extensive network of linear molecule connected by dimeric NH⋯O bonds stacked on top of each other stabilized by non-bonded interactions involving fluorine atoms, which do not take part in the hydrogen bonding network.