Hydrochloric Acid → HCID 178448321, compound

Participants

Reaction Conditions

Reaction Steps

Aqueous sodium hydroxide solution 10 M (approximately 41 ml; 410 mmol) is added to a stirred suspension of L-Valine (24.8 g; 210 mmol) and 2′-(1H-tetrazol-5-yl)-biphenyl-4-carbaldehyde (50 g; 200 mmol) in water (200 ml) at room temperature, until pH 11 is reached. The resulting clear solution is evaporated at 60° C. in vacuo, and remaining water is azeotropically removed with 1-butanol. The residue (imine as a solid foam) is dissolved in methanol (600 ml), and sodium borohydride (3.13 g; 80 mmol) is added in portions to the solution at 0-5° C. The reaction mixture is stirred for 30 min at 0-5° C., and, if the reaction is complete (HPLC), quenched by addition of water (300 ml) and hydrochloric acid 2.0 M (160 ml; 320 mmol). The organic solvent (methanol) is stripped off from the clear solution (pH 7) at 50° C. in vacuo. The remaining aqueous concentrate is adjusted to pH 2 by slow addition of hydrochloric acid 2.0 M (approximately 90 ml) at 40° C. During the addition the desired product precipitates. It is collected by filtration, washed with water and dried in vacuo. The crude product is suspended in methanol at 50° C., and stirred for a few minutes. Then the slurry is cooled to room temperature. (S)-3-methyl-2-((2′-(1H-tetrazol-5-yl)-biphenyl-4-yl-methyl)-amino)-butyric acid is collected by filtration and then dried in vacuo.

Provenance & Evidence