Figure 2.
Synthetic scheme for compounds 1a–b and 4a–b: i) Glutaric anhydride (1 eq.), 5a–b (2 eq.) in Pyridine/DCM (1:1) under N2, r.t. 16h; ii) 4-amino-TEMPO (2 eq.), WSC (1.1 eq.) in DCM/DMF (9:1); iii) 10a–b (1 eq.), methyl diethyl phosphonoacetate (1.1 eq.), LiOH (1 eq.) in THF under Ar; iv) MeOH/NaOH 2M (1:1) at 80 °C, 2h.