The design and synthesis of 10-(2-benzoxazolcarbonyl)-DDACTHF (1) as an inhibitor of glycinamide ribonucleotide transformylase (GAR Tfase) and aminoimidazole carboxamide transformylase (AICAR Tfase) are reported. Ketone 1 and the corresponding alcohol 13 were evaluated for inhibition of GAR Tfase and AICAR Tfase and the former was found to be a potent inhibitor of recombinant human (rh) GAR Tfase (Ki= 600 nM).