4-Amino-1,2,2,6,6-pentamethylpiperidine → 4-(5,6-Dichlorobenzimidazol-2-yl)-N-(1,2,2,6,6-pentamethylpiperidin-4-yl)-3-methoxybenzamide

Participants

Reaction Steps

A solution of 5,6-dichloro-2-(4-carboxy-2-methoxyphenyl)benzimidazole (0.8 g, 2,36 mmol), prepared as described in Preparation 6,1-hydroxybenzotriazole (0.32 g, 2.36 mmol) and N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (0.56 g, 2.9 mmol) in 80 ml of DMF/THF (50:50) was refluxed for 5 h. A solution of 1,2,2,6,6-pentamethyl-4-aminopiperidine (0.5 g, 2.9 mmol) in THF (5 ml) was added dropwise and the reaction was refluxed for additional 3 h. After cooling, solvent was removed under reduced pressure and the residue was treated with 1N NaOH (10 ml) and extracted with dichloromethane (50 ml). The organic layer was washed with water, dried over Na2SO4, filtered and evaporated under reduced pressure. The residue was triturated with diisopropyl ether (150 ml), stirred for 1 h, filtered to give 0.55 g of the title compound (yield 47.6%), mp=285–286° C.

Provenance & Evidence