The antiviral activity of compounds 1, 2, 3a-d, 4a-d against vesicular stomatitis virus (VSV) was evaluated at four different concentrations (Figure ). Compounds 4b-d exhibited good antiviral activity, while 3b and 3c were able to inactivate viruses only at a higer concentration of 50 μM. Compounds 3a, 3d and 4a were practically inactive. Interestingly, the initial derivatives 1 and 2 showed the highest activity against VSV in the whole series.