5-[Bis(2-hydroxyethyl)amino]-1-methyl-1H-benzimidazole-2-butanoic acid ethyl ester

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[1-Methyl-5-bis(2’-hydroxyethyl)aminobenzimidazolyl-2]butanoic Acid Ethyl Ester_x000D_Bendamustine Related Impurity 1 (cas# 3543-74-6) is a compound useful in organic synthesis.

Stir and dissolve 5-amino-1-methyl-1H-2-benzimidazole butyric acid ethyl ester (60g, 0.23mol), 600mL water, and 300mL glacial acetic acid in a 2L reaction flask, and cool to -50, Add 120 mL of ethylene oxide, and control the temperature to complete the reaction. Adjust the pH of the potassium carbonate solution to 7.0-7.3, extract with dichloromethane 300 mL×3, combine the organic phases, wash with purified water 200 mL×3, dry with anhydrous magnesium sulfate, filter, and concentrate to obtain a brown solid. Then add 1200 mL of ethyl acetate and heat to 70-80° C. to dissolve, cool to room temperature to crystallize, filter and dry to obtain 63 g of light brown solid 5-[Bis(2-hydroxyethyl)amino]-1-methyl-1H-benzimidazole-2-butanoic acid ethyl ester with a purity of 99.3%. The yield was 78.5%.