Citric Acid → 4'-((R)-2-(tert-butoxycarbonylamino)-4-((R)-3-(1-(3-methoxypropyl)-1H-benzo[d]imidazol-2-yl)piperidin-1-yl)-4-oxobutyl)biphenyl-4-carboxylic acid

Participants

Reaction Steps

Methyl 4′-((R)-2-(tert-butoxycarbonylamino)-4-((R)-3-(1-(3-methoxypropyl)-1H-benzo[d]imidazol-2-yl)piperidin-1-yl)-4-oxobutyl)biphenyl-4-carboxylate (53A) (prepared by the procedure for Example 53, Step A) (0.815 mmoles, 0.545 g) was added to a 25 mL round-bottomed flask equipped for stirring under nitrogen. Tetrahydrofuran (2 mL), methanol (1 mL), and LiOH (2.0 mmoles, 1.0 mL of 2N in H2O) were then added and the resultant solution was allowed to stir at room temperature for 16 hrs. Citric acid (2.09 mmoles, 0.403 g) in H2O (1 mL) was then added and the resultant solution was concentrated in-vacuo, filtered, and then purified by preparative LC/MS. The resultant fractions were collected and the solvent was removed in-vacuo affording a brown colored oil. This oil was re-dissolved in CH3CN (1 mL) and water (2 mL). The resultant solution was frozen and lyophilized to afford 4′-((R)-2-(tert-butoxycarbonylamino)-4-((R)-3-(1-(3-methoxypropyl)-1H-benzo[d]imidazol-2-yl)piperidin-1-yl)-4-oxobutyl)biphenyl-4-carboxylic acid (86A) as a tan flocculent solid (0.637 mmoles, 0.417 g, 78% yield). ESI-MS: m/z 655.5 (M+H)+.

Provenance & Evidence