(R)-alpha-[(2-t-Butoxycarbonylamino-2-methyl-1-oxopropyl)amino]-1H-indole-3-propanoic acid, benzyl ester → (R)-2-(2-((tert-Butoxycarbonyl)amino)-2-methylpropanamido)-3-(1H-indol-3-yl)propanoic acid

Participants

Reaction Steps

The benzyl ester (0.82 g, 1.71 mmol) obtained in Step C and 10% palladium on carbon (150 mg) were stirred together in ethyl acetate (5 mL). The solution was degassed and a hydrogen atmosphere introduced over the reactants using a balloon for 32 hours. The reaction products were isolated by filtering the reaction mixture through a Celite plug. The plug was washed with additional ethyl acetate (3×10 mL). The combined filtrates were evaporated under vacuum to afford the product (680 mg, 102%). 1H NMR (400 MHz, CDCl3): 1.30 (s, 9H), 1.41 (s, 6H), 3.32 (dd, 1H), 3.42 (m, 1H), 4.87 (br s, 1H), 6.82 (d, 1H), 7.13-7.35 (m, 8H), 7.60 (d, 1H), 8.28 (br s, 1H).

Provenance & Evidence