Fig. 2.

SAR studies around the AK-24 scaffold. The bar graph shows the inverse IC₅₀ estimated from inhibition at four concentrations (n = 3 to 4 for each concentration), as in Fig. 1. Substitutions around the C3-OBn ring are destabilizing. Combining the substitutions of AK-24 and AK-33 has a synergistic effect on inhibitor potency (AK-42, purple). Data are given in Table 2.