Synthesis of N-aryl uracils and hypoxanthines and their biological properties

1-Benzyluracils 2a,b were treated with iodobenzene in the presence of cupro us oxide in 2,4,6-trimethylpyridine at 180 degrees C to give the N'-phenyl derivatives 3a and 3b in 47% and 55%, respectively. Similar reaction of 2a with 2-bromopyridine at 120 degrees C gave the 3-(2-pyridinyl)uracil 4a in 42% yield. However, unusual product 5 as well as 3-(2-pyridinyl) derivative 4b were obtained in the case of 2b. The structure of 5 was identified as 1 -(2,6-difluorobenzyl)-3-[(2,4-dimethyl-2-pyridinyl)methyl]uracil from spect roscopic data Reaction of the hypoxanthines 7a,b with 2-bromopyridine gave the 1-(2-pyridinyl)hypoxanthines 8a,b in low yields. But N-phenylation of 7 a,b were unsuccessful.