SYNTHESIS OF C-14-LABELED PIRITREXIM - A POTENTIAL ANTICANCER AGENT

Piritrexim 1 (2,4-diamino-6-(2,5-dimethoxybenzyl)-5-methylpyrido[2,3-d]pyrimidine) was synthesized in the [C-14]-labelled form with specific activity 50.8 mCi/mmol suitable for drug metabolism, transport, disposition and mechanism of action studies. The synthetic sequence involved synthesis of the novel 2-bromo-5-(2,5-dimethoxybenzyl)-4-methyl-3-pyridinecarbonitrile and condensation of this compound with [C-14]-guanidine hydrochloride. The radiochemical purity was > 98%.