The present invention relates to a method for preparation of alkyl 4-[5-[bis(2-hydroxyethyl)amino]-1-methyl-1H-benzimidazol-2-yl]butanoate (7) from 2-fluoro-5-nitroaniline, comprising the steps of: (a) conversion of 2-fluoro-5-nitroaniline to 5-(2-fluoro-5-nitroanilino)-5-oxopentanoic acid (1) using glutaric anhydride, conversion of compound (1) to methylammonium 5-[2-(methylamino)-5-nitroanilino]-5-oxopentanoate (2) using methylamine; conversion of compound (2) to 5-[2-(methylamino)-5-nitroanilino]-5-oxopentanoic acid (3) and condensation of compound (3) to 4-(1-methyl-5-nitro-1H-benzimidazol-2-yl)butanoic acid (4); (b) esterification of the product (4) of step a) to alkyl 4-(1-methyl-5-nitro1H-benzimidazol-2-yl)butanoate (5); (c) reduction of the product of step b) to alkyl 4-(5-amino-1-methyl-1H-benzimidazol-2-yl)butanoate (6), and (d) conversion of the product of step c) to alkyl 4-[5-[bis(2-hydroxyethyl)amino]-1-methyl-1H-benzimidazol-2-yl]butanoate (7)
该发明涉及一种从
2-氟-5-硝基苯胺制备烷基4-[5-[双(2-羟乙基)
氨基]-1-甲基-1H-
苯并咪唑-2-基]
丁酸酯(7)的方法,包括以下步骤:(a)将
2-氟-5-硝基苯胺转化为5-(
2-氟-5-硝基苯胺基)-
5-氧代戊酸(1),使用
戊二酸酐,将化合物(1)转化为
甲胺基5-[2-(甲基
氨基)-5-
硝基苯胺基]-
5-氧代戊酸酯(2),使用
甲胺;将化合物(2)转化为5-[2-(甲基
氨基)-5-
硝基苯胺基]-
5-氧代戊酸(3),并将化合物(3)缩合为4-(1-甲基-5-硝基-1H-
苯并咪唑-2-基)
丁酸(4);(b)酯化步骤a)的产物(4)为烷基4-(1-甲基-5-硝基1H-
苯并咪唑-2-基)
丁酸酯(5);(c)还原步骤b)的产物为烷基4-(5-
氨基-1-甲基-1H-
苯并咪唑-2-基)
丁酸酯(6),以及(d)将步骤c)的产物转化为烷基4-[5-[双(2-羟乙基)
氨基]-1-甲基-1H-
苯并咪唑-2-基]
丁酸酯(7)。