6-Aminohexanoic Acid → HCID 57796841, compound

Participants

Reaction Steps

(Method J15E) A solution of 3-(1H-indol-3-yl)-2-(4-1H-indol-3-yl-butyrylamino)-propionic acid (16/97) (2.628 g, 6.75 mmol) and N-hydroxysuccinimide (0.776 g, 6.75 mmol) in acetonitrile at 0° C. was treated with N,N′-dicyclocarbodiimide (1.400 g, 6.8 mmol) The resulting suspension was allowed to stand at 15° C. for 3 hours, the precipitate was filtered off and washed with acetonitrile (2×15 ml). To the filtrate was added a solution of 6-aminohexanoic acid (0.881 g, 6.72 mmol) and NaHCO3 (1.014 g, 13 mmol) in water (20 ml) and the resulting mixture was stirred at room temperature for 3 hours. Acetonitrile was evaporated under reduced pressure, the residue was acidified with citric acid to pH 2 and extracted with ethyl acetate (100 ml). The organic layer was washed with water (2×20 ml), brine (20 ml), and dried (MgSO4). The solvent was evaporated and the residue was dissolved in tetrahydrofuran (100 ml). To the obtained solution under argon atmosphere 1,1′-carbonyldiimidazole was added and the mixture was stirred at room temperature for 40 min. To the reaction mixture a suspension of O-benzylhydroxylamine hydrochloride (1.053 g, 6.60 mmol) and triethylamine (0.666 g, 6.60 mmol) in tetrahydrofuran (30 ml) was added and the resulting suspension was vigorously stirred at room temperature for 24 hours. The mixture was evaporated and the residue was dissolved in ethyl acetate (150 ml). The solution was washed successively with water (2×20 ml), 5% citric acid (20 ml), water (20 ml), brine (20 ml), and dried (MgSO4). The solvent was removed and the residue was crystallized from ethyl acetate to give the title product (2.163 g, 53%). 1H NMR (DMSO-d6, HMDSO) δ: 1.02-1.60 (6H, m); 1.64-2.36 (8H, m); 2.80-3.20 (4H, m); 4.33-4.66 (1H, m); 4.78 (2H, s); 6.84-8.03 (17H, m); 10.73 (1H, s); 10.91 (1H, s).

Provenance & Evidence