SYNTHESIS OF SUBSTITUTED 1-NORBORNYLAMINES WITH ANTIVIRAL ACTIVITY

The reaction of (+/-)-camphor (7) with triflic anhydride (Tf(2)O) yiel ds the bridgehead triflate 8. The Nametkin rearrangement of 8 to 3 was realized by treatment with triflic acid (TfOH). The solvolysis of the bridgehead triflates 3 and 8 in acetonitrile affords the N-acetyl-1-n orbornylamines 4 and 9. The Pd(0)-catalyzed hydrogenation of 4 and 9 g ives the amides 5 and 10. The corresponding 1-norbornylamines 2 and 13 and the N-ethyl derivatives 1, 6, 11, and 12 were obtained by basic h ydrolysis or reduction with LiAlH4, respectively, of the amides 4, 5, 9, and 10. The antiviral activity of the hydrochlorides of some of the obtained 1-norbornylamines was evaluated against influenza A, herpes simplex 2, and African swine fever virus. Particularly noticeable is t he activity of the hydrochlorides of 1 and 11 against influenza A viru s (SI (selectivity index) = 1000).