a study of the structure-activity relationship of a series of newly synthesized phosphonylmethoxyalkyl purine and pyrimidine derivatives revealed that several adenine derivatives substituted at the n9 position by a 2-phosphonylmethoxyethyl ( pme ) group inhibited human immunodeficiency virus ( hiv ) -induced cytopathogenicity and hiv antigen expression in vitro at concentrations significantly below the toxicity threshold for the host cells .
C0034140
purine
C0001407
adenine