Yield:-

Reaction Conditions:

Stage #1:methyl 4'-[2-n-propyl-4-methyl-6-hydroxycarbonyl-benzimidazol-1-yl]-methyl-biphenyl-2-carboxylate with potassium hydroxide;water in N,N-dimethyl acetamide at 70 - 75; for 2 - 3 h;
Stage #2: with hydrogenchloride in water; pH=4 - 5 at 25 - 35; for 0.5 - 0.75 h;

Steps:

18
EXAMPLE 18; PREPARATION OF 4'- [2-n-PROPYL-4-METHYL-6-CARBOXYLIC ACID- BENZIMIDAZOL-1-YL] -METHYL-BlPHENYL-2- CARBOXYLIC ACID (FORMULA XV); 15 g of the acid ester of Example 14 and 8.4 g of potassium hydroxide were charged into a round bottom flask containing 225 ml of acetonitrile. The contents were heated to 70-75° C and stirred for 2-3 hours. Reaction completion was confirmed by thin layer chromatography and the solvent was distilled completely under vacuum. Reaction mass was cooled to 25-35° C and charged 225 ml of water. Reaction mass pH was adjusted to 4-5 with 36% aqueous hydrochloric acid (12 ml) and stirred for 30-45 minutes. Filtered the solid and washed with 30 ml of water.The wet solid was charged into a flask containing 70 ml of acetonitrile at room temperature. Stirred for 30-45 minutes, filtered the solid and washed with acetonitrile (20 ml). Dried the solid at 25-35° C for 4-5 hours to get 10 g of the title compound.

References:

DR. REDDY'S LABORATORIES LTD.;DR. REDDY'S LABORATORIES, INC. WO2006/44754, 2006, A2 Location in patent:Page/Page column 37