Scheme 1.

Synthesis of Imidazole-Imine Series Compounds 2–15^a

^aR¹ is defined in Table 1. Conditions: (a) 3,5-dimethoxybenzylamine, NaBH(OAc)₃, CH₂Cl₂, rt, overnight, then 1,4-dioxane, 110 °C, 99%; (b) phenyl triflimide, i-Pr₂NEt, THF/CH₂Cl₂, rt, overnight, 79%; (c) B₂Pin₂, KOAc, PdCl₂(dppf)·CH₂Cl₂, 1,4-dioxane, 100 °C overnight, 99%; (d) CuBr₂, MeOH/H₂O, 80 °C, 90%; (e) LiBHEt₃ (1 M THF), THF, 0 °C, 1 h, 41%; (f) PBr₃, CH₂Cl₂, 0 °C, 42%; (g) 1-methyl-1H-imidazol-2-amine hydrochloride, i-Pr₂NEt, MeCN, 60 °C, overnight, quant.; (h) R¹–B(OH)₂ or R¹–B(Pin), PdCl₂(dppf)·CH₂Cl₂, K₂CO₃, 1,4-dioxane/H₂O, 80 °C, overnight, 20–70%.