Lithium Hydroxide → 1-{3-[(tert-butoxycarbonyl)amino]propyl}-2-[(3,4,5-trimethoxyphenyl)amino]-1H-benzimidazole-6-carboxylic acid

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Reaction Steps

Lithium hydroxide (2.18 g, 6 eq) is added to a solution of methyl 1-{3-[(tert-butoxycarbonyl)amino]propyl}-2-[(3,4,5-trimethoxyphenyl)amino]-1H-benzimidazole-6-carboxylate (4.4 g, 1 eq) in a mixture of tetrahydrofuran (40 ml) and water (30 ml). The mixture is heated under reflux for 18 hours then cooled down to ambient temperature and concentrated under reduced pressure at 40° C. Dichloromethane (150 ml) and water (100 ml) are added to the residue. The mixture is acidified by the addition of acetic acid to pH 5. After decantation and extractions, the combined organic phases are dried over sodium sulphate and concentrated under reduced pressure. The solid obtained is washed with ethyl ether (3.95 g; 93%).

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