Synthesis and bronchodilating activity of 2,9-disubstituted adenine derivatives BB-1502 (9-cyclohexyl-2-n-propoxy-9H-adenine) and its analogs.

A series of 2, 9-disubstituted adenine derivatives was prepared and evaluated for bronchodilating activity. 9-(2-Cyclohexenyl), 9-tetrahydropyranyl and 9-benzyl derivatives of 2, 6-dichloropurine were converted to the 2-chloroadenines. Subsequent nucleophilic substitution of the 2-chloro group with alkoxides, mercaptides and amines afforded the desired compounds. 9-Cyclohexyl derivatives were prepared by hydrogenation of the corresponding 9-cyclohexenyl compounds. Bronchodilating activities of the new adenine derivatives were evaluated in a number of biological systems. 9-(2-Cyclohexenyl)- and 9-cyclohexyladenines having an ethoxy, n-propoxy, n-butoxy or n-propylthio group at the 2-position showed potent bronchodilating activity. Reduced activity was observed with lower or higher alkoxy homologs and branched alkoxy congeners. 9-Cyclohexyl-2-n-propoxy-9H-adenine (designated as BB-1502) was selected for further studies in view of its high intrinsic activity and favorable pharmacological profile.