Scheme 4. Synthesis of Candidate 2, Leveraging the Symmetry of Diester–Imidazole 11.

Reagents and conditions: (a) K₂CO₃, H₂O/EtOH, H₂NOSO₃H, 0–25 °C, 78%; (b) DIPEA, 2-Me-THF, reflux; (c) NBS, HOAc/MeCN, 70 °C, 48%, 2 steps; (d) 1,2,4-triazole, POCl₃, NEt₃, CH₂Cl₂; (e) pyrrolidine, NEt₃, CH₂Cl₂, 25 °C, 86%, 2 steps; (f) 10, Pd(dppf)Cl₂·CH₂Cl₂, Na₂CO₃, dioxane/H₂O, 110 °C, 91%; (g) LiBH₄, THF, 50 °C, 98%; (h) 1 M HCl, THF, reflux, 92%.