反应详情

1-(4-chloro-2-fluoro-5-hydroxyphenyl)-4-(3-fluoropropyl)-1,4-dihydro-5H-tetrazol-5-one is etherified with 4-fluoronitrobenzene in the presence of potassium carbonate in N,N-dimethylformamide to form 1-[4-chloro-2-fluoro-5-(4-nitrophenoxy)phenyl]-4-(3-fluoropropyl)-1,4-dihydro-5H-tetrazol-5-one (Compound A). Compound A is then reduced with iron powder in acetic acid and water to produce 1-[5-(4-aminophenoxy)-4-chloro-2-fluorophenyl]-4-(3-fluoropropyl)-1,4-dihydro-5H-tetrazol-5-one (Compound B). Acetone is added to a stirring mixture of Compound B in hydrochloric acid. The mixture is cooled to about 5° C., and a solution of an equimolar amount of sodium nitrite in water and a molar excess of methyl acrylate are added in succession. The resultant mixture is stirred for 15-20 minutes, after which copper (I) chloride is slowly added. The mixture is stirred at room temperature for approximately 30 minutes and then poured into ice water. The resulting mixture is then treated with an organic solvent (e.g., ethyl acetate) to extract the product, methyl 2-chloro-3-[4-[2-chloro-4-fluoro-5-[4-(3-fluoropropyl)-1,4-dihydro-5H-5-oxo-tetrazol-1-yl]phenoxy]phenyl]propionate, which may then be purified, as by column chromatography on silica gel.