Dabigatran etexilate (N-[2-{4-[N-(hexyloxycarbonyl)amidino]phenylaminomethyl}-1methyl-1H-benzimidazol-5-ylcarbonyl]-N-(2-pyridyl)-β-alanine ethyl ester, 9) is a selective, reversible, and direct inhibitor of thrombin; it has been clinically developed for the prevention of venous thrombolism and cardioembolic stroke.1–3 A key intermediate in the preparation of dabigatran etexilate is reported4,5 to be 3-[(3-amino-4-methylaminobenzoyl)pyridin-2-yl-amino]propionic acid ethyl ester (6), which has been obtained from 4-methylamino-3-nitrobenzoic acid (1) in only 25∼50% overall yield (Scheme 1).4–6

中文翻译：

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3-[(3-Amino-4-methylaminobenzoyl pyridin-2-yl)amino]丙酸乙酯的新型一锅法合成

达比加群酯（N-[2-{4-[N-（己氧羰基）脒基]苯基氨基甲基}-1甲基-1H-苯并咪唑-5-基羰基]-N-（2-吡啶基）-β-丙氨酸乙酯，9）是一种选择性、可逆和直接的凝血酶抑制剂；它已在临床上开发用于预防静脉血栓形成和心源性中风。1-3 据报道，制备达比加群酯的关键中间体 4,5 是 3-[(3-amino-4-methylaminobenzoyl)pyridin-2-yl -氨基]丙酸乙酯(6)，从4-甲氨基-3-硝基苯甲酸(1)得到的总产率仅为25~50%(方案1).4-6