p-Fluoronitrobenzene → 2-(4-bromo-benzyl)-1-(4-nitro-phenyl)-4-(2,4-dichloro-phenyl)-1H-imidazole

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Reaction Steps

2-(4-Bromo-benzyl)-4-(2,4-dichlorophenyl)-1H-imidazole (3.27 g, 8.6 mmol) was treated as described in general procedure B using 4-fluoronitrobenzene to provide 2-(4-bromo-benzyl)-4-(2,4-dichloro-phenyl)-1-(4-nitro-phenyl)-1H-imidazole, which was treated with 4-hydroxyphenyl boronic acid according to general procedure G to provide 4′-[4-(2,4-dichloro-phenyl)-1-(4-nitro-phenyl)-1H-imidazol-2-ylmethyl]-biphenyl-4-ol (996 mg, 22% for two steps). To a solution of the phenol in THF (0.5 M) was added N-boc-4-hydroxypiperidine (2 eq) and triphenylphosphine (2 eq) under nitrogen, then while sonicating this mixture diisopropyl azodicarboxylate (2 eq) was added. After sonicating 1 hour the reaction mixture was evaporated in vacuo and the reside was purified by silica gel column chromatography to afford 4-{4′-[4-(2,4-dichloro-phenyl)-1-(4-nitro-phenyl)-1H -imidazol-2-ylmethyl]-biphenyl-4-yloxy}-piperidine-1-carboxylic acid tert-butyl ester.

Provenance & Evidence