申请人:Eisai Co., Ltd.
公开号:US05608068A1
公开(公告)日:1997-03-04
The present invention provides an industrially advantageous process for preparing a 2-alkyl-3-(biphenyl-4-yl)methyl-3H-imidazo[4,5-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-[4,5-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,该衍生物表示为以下式子(II),该衍生物是一种抗肾素II受体拮抗剂的前体,用作降压药物,一种联苯衍生物,它是吡啶衍生物的取代基的前体,一种用于制备联苯衍生物的中间体:##STR1## 该2-烷基-3-(联苯基-4-基)甲基-3H-咪唑[4,5-b]吡啶衍生物可以通过酰胺化、N-烷基化和还原环化从2-氨基-5-卤代-3-硝基吡啶衍生物中高产得到。在随后进行的步骤中,作为对硝化的保护基引入的卤原子可以同时消除。因此,此过程在工业上具有优点。此外,本发明的联苯衍生物在反应性和产品纯度方面均优异,因此是适用于工业生产的中间体。