Hydrochloric Acid → HCID 72558430, compound

Participants

Reaction Steps

A solution of triethylamine (3.1 mL, 1.1 equivalent) and methyl 4-aminobutyrate hydrochloride (3.2 g, 1.05 equivalent) in 25 ml of anhydrous N,N-dimethylformamide was stirred at −10° C. under N2 atmosphere for 10 minutes. Sequential addition of Boc-L-alanine (3.8 g, 1.0 equivalent), N-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (4.2 g, 1.1 equivalents), 1-hydroxybezotriazole (1.8 g, 0.6 equivalent), and 15 mL of anhydrous N,N-dimethylformamide was carried out at the same temperature. The final solution was stirred under N2 atmosphere at room temperature overnight and diluted with ethyl acetate. The resulting solution was washed sequentially with 1 M HCl(aq), saturated NaHCO3(aq), and saturated NaCl(aq), followed by a rapid filtration through a pad of silica gel and Na2SO4. The filtrate was concentrated and dried under reduced pressure to give a crude paste (4.8 g). The paste was stirred in a mixture of 50 mL of tetrahydrofuran, 25 mL of methanol, and 20 mL of water with the presence of LiOH (0.45 g, 1.1 equivalents) for 1 hour at room temperature. The solution was acidified with concentrated HCl and extracted with ethyl acetate. The organic extracts were combined and washed with saturated NaCl(aq) and rapidly filtered through a pad of silica gel and Na2SO4. The filtrate was concentrated and dried under reduced pressure to give 4-(2-t-butoxycarbonylamino-propionylamino)butyric acid as a paste (4.0 g, 72% yield); H1-NMR (DMSO-d6), δ=1.1 ppm (d, 3H), 1.3 ppm (s, 9H), 1.6 ppm (p, 2H), 2.2 ppm (t, 2H), 3.0 ppm (m, 2H), 3.8 ppm (m, 1H), 6.8 ppm (d, 1H), 7.8 ppm (t, 1H).

Provenance & Evidence