PROCESS FOR PRODUCING IMIDAZOPYRIDINE DERIVATIVE AND INTERMEDIATE

摘要

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.