139481-69-9

139481-44-0

139481-69-9

1. Methyl 2-ethoxy-1-[(2'-cyanobiphenyl-4-yl)methyl]-1H-benzimidazole-7-carboxylate (310 g) and toluene (2.48 L) were added to a reactor, followed by tributyltin chloride (737 g), sodium azide (146 g) and tetrabutylammonium bromide (31 g). 2. The reaction mixture was slowly heated to 110 °C and maintained at 110-115 °C for 24 h, during which the progress of the reaction was monitored by TLC. 3. After completion of the reaction, the reaction mixture was cooled to 15 °C and methanol (3.1 L), water (2.17 L) and acetic acid (930 g) were added sequentially. 4. The mixture was stirred at 15-20 °C for 1 h to promote product separation. 5. After addition of toluene (1.24 L), the reaction mixture was filtered at 15-20 °C. 6. the filter cake was washed thoroughly with water (0.93 L) until the pH of the wash solution reached 5.5-7.0 to completely remove the acid. 7. The filter cake was washed again with toluene (0.62 L) and dried by suction filtration. 8. The product was air dried at 50-55 °C to give methyl 2-ethoxy-1-[[(2'-(1H-tetrazol-5-yl)biphenyl-4-yl)methyl]benzimidazole]-7-carboxylate. Yield: 290 g (85%).