We report herein the synthesis and the in vitro antileishmanial evaluation of a series of 6-substituted purines. The most active compounds against Leishmania amazonensis promastigotes were 6-(3'-chloropropylthio)purine 2 (D.A. Benson, I. Karsch-Mizrachi, D.J. Lipman, J. Ostell, B.A. Rapp, D.L. Wheeler, Genbank., Nucleic Acids Res. 28 (2000) 15-18; E.V. Aleksandrova, P.M.I.E. Valashek, J. Med. Pharm. Chem. 35 (2001) 172-173), 6-(3'-(thioethylamine)propylthio)purine 5, 6-(alpha-aceticacidthio)purine-7 and 6-(6'-deoxy-1'-O-methyl-beta-D-ribofuranose)purine 14 with an IC50 = 50, 50, 39 and 29 mu M, respectively. (c) 2006 Elsevier Masson SAS. All rights reserved.