申请人:Eisai Co., Ltd.
公开号:EP0627433A1
公开(公告)日:1994-12-07
The invention provides an industrially excellent process for producing a 2-alkyl-3-(biphenyl-4-yl)-methyl-3H-imidazo[4,5-b]pyridine derivative represented by general formula (II), serving as a precursor of the angiotensin II receptor antagonist useful as an antihypertensive, a biphenyl derivative serving as a precursor of the substituent of the imidazopyridine derivative, a process for producing the biphenyl derivative, and an intermediate useful for producing the biphenyl derivative. The imidazopyridine derivative (II) can be produced in a high yield according to the process of the invention by subjecting a 2-amino-5-halogeno-3-nitropyridine derivative to amidation, N-alkylation and reductive cyclization. This process is industrially excellent, because the halogen atom introduced into the 5-position as a protective group in the nitration step can be eliminated simultaneously in the subsequent step. The above biphenyl derivative is excellent in reactivity and product purity, thus being an intermediate suitable for industrial production.
本发明提供了一种生产通式(II)代表的 2-烷基-3-(联苯-4-基)-甲基-3H-咪唑并[4,5-b]吡啶衍生物的工业化优良工艺,该衍生物可作为血管紧张素 II 受体拮抗剂的前体,用于抗高血压、作为咪唑并吡啶衍生物取代基前体的联苯衍生物,生产联苯衍生物的工艺,以及生产联苯衍生物的中间体。根据本发明的工艺,通过对 2-氨基-5-卤代-3-硝基吡啶衍生物进行酰胺化、N-烷基化和还原环化,可以高产率生产出咪唑吡啶衍生物 (II)。由于在硝化步骤中作为保护基团引入 5 位的卤素原子可以在后续步骤中同时消除,因此该工艺在工业上非常出色。上述联苯衍生物在反应活性和产品纯度方面都非常出色,因此是一种适合工业化生产的中间体。