反应详情

A reaction of 5-nitrobenzimidazole (3.3 g, 20 mmol) and 2-hydroxyethyl bromide (2.2 ml, 31 mmol) in a procedure described in Example 9 produces a mixture of 1- and 3-(2-5 hydroxyethyl)-5-nitrobenzimidazole, which was converted to the corresponding amines in hydrogenation (H2/Pd—C). The amine mixture (3.4 g, 19 mmol) in 50 ml of AcOH was added solution of Br2 in AcOH until it produces a precipitation. The reaction mixture was concentrated in vacuo to provide a brown solid which was subjected to column chromatography (5% NH3 sat'd isopropanol/CHCl3) to provide 0.42 g (1.6 mmol) of 3-(2-hydroxyethyl)-4-bromo-5-aminobenzimidazole and 0.57 g (2.2 mmol, 11%) of 1-(2-hydroxyethyl) -4-bromo-5-aminobenzimidazole.

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