Pyrimidine analogs of antimycobacterial 6-aryl-9-benzylpurines have been synthesized and screened for antibacterial activity against Mycobacterium tuberculosis H(37)Rv in vitro. Several active compounds were identified and the best results were observed for 5-formamidopyrimidines. These compounds generally displayed IC(90) values < or =1microg/mL, and they exhibited low toxicity towards mammalian cells. Imidazolylpyrimidines, which may be regarded as fleximer analogs of the parent purines, were also synthesized and one of them was found to be quite a potent inhibitor of M. tuberculosis (IC(90) 14microg/mL).