From a group of pyrrolo [2, 3-d] pyrimidine compounds that have been screened against influenza virus, one derivative, 4-(3-piperidinyl benzylamino)-2-methyl-7H-pyrrolo [2, 3-d] pyrimidine (9), has shown promising activity against both the A and B strains. The compound had activity comparable to amantadine, but was inactive when given orally. 4- (Substitutedphenyl ethylamino)-2-methyl-7H-pyrrolo [2, 3-d] pyrimidines showed no ...