Synthesis and biological evaluation of 2,8-disubstituted 9-benzyladenines: Discovery of 8-mercaptoadenines as potent interferon-inducers

Recently, we have identified 9-benzyl-8-hydroxyadenines bearing an appropriate substituent (a butoxy, propylthio or butylamino group) at the 2-position as potent interferon (IFN)-inducers. Herein we report the design, synthesis, and IFN-inducing activity of 8-substituted 9-benzyladenines possessing such an appropriate substituent at the 2-position. Introduction of the appropriate substituent into the 2-position of the adenine nucleus gave rise to expression of the activity even in 9-benzyladenines bearing no hydroxyl group at the 8-position. An amino group at the 6-position and a hydroxyl or thiol group carrying an acidic proton at the 8-position are required to express excellent IFN-inducing activity. 9-Benzyl-2-butoxy-8-mercaptoadenine (9) indicated the most potent activity with MEC of 0.001 muM. (C) 2003 Elsevier Science Ltd. All rights reserved.