申请人:Eisai Co., Ltd.
公开号:US05700938A1
公开(公告)日:1997-12-23
The present invention provides an industrially advantageous process for preparing a 2-alkyl-3-(biphenyl-4-yl)methyl-3H-imidazo\x9b4,5-b!pyridine derivative represented by the following formula (II) which is a precursor of an antagonist against an angiotensin II receptor useful as an antihypertensive drug, a biphenyl derivative which is a precursor of the substituent of the pyridine derivative, a process for the preparation thereof, and an intermediate useful for the preparation of the biphenyl derivative: ##STR1## The 2-alkyl-3-(biphenyl-4-yl)methyl-3H-imidazo\x9b4,5-b!pyridine derivative can be prepared in a high yield according to the present invention from a 2-amino-5-halogeno-3-nitropyridine derivative through amidation, N-alkylation and reductive cyclization. The halogen atom introduced at the 5-position as a protective group against nitration can be eliminated simultaneously in the step which is conducted thereafter. Thus, this process is industrially advantageous. Further, the biphenyl derivative of the present invention is excellent in reactivity and purity of the product, thus being an intermediate suitable for the industrial production.
本发明提供了一种工业上有利的制备2-烷基-3-(联苯基-4-基)甲基-3H-咪唑[4,5-b]吡啶衍生物的方法,该衍生物由以下式子(II)表示,是一种抗肾素II受体拮抗剂的前体,可用作降压药物,联苯衍生物是吡啶衍生物取代基的前体,提供了其制备方法和用于制备联苯衍生物的中间体:##STR1## 根据本发明,可以通过酰胺化,N-烷基化和还原环化从2-氨基-5-卤代-3-硝基吡啶衍生物高收率地制备2-烷基-3-(联苯基-4-基)甲基-3H-咪唑[4,5-b]吡啶衍生物。在随后进行的步骤中,引入的5位卤素原子作为对硝化的保护基可以同时消除。因此,这个过程具有工业上的优点。此外,本发明的联苯衍生物在反应性和产物纯度方面都很优秀,因此是适用于工业生产的中间体。