No

R¹

R²

R³

IC₅₀ (μM)

5

H

H

p-MeO-Ph-

2.8

17

Me

H

p-HO-Ph-

3.3

18

Me

H

p-MeO-Ph-

5.5

19

Me

H

p-F-Ph-

1

23

Me

H

2,5-diMeO-Ph-

31.7