Synthesis of 10-acetyl-5,8-dideazafolic acid: a potent inhibitor of glycinamide ribonucleotide transformylase

10-Acetyl-5,8-dideazafolic acid has been synthesized in good yield from the parent compound, 5,8-dideazafolic acid. This quinazoline folate analogue showed no activity as a substrate for the folate-requiring de novo purine biosynthetic enzyme glycinamide ribonucleotide transformylase isolated from the murine lymphoma cell line L5178Y, but proved to be a potent competitive inhibitor, Ki = 1.3 microM, of the purified enzyme.