Pyridine → Tert-butyl 2-{[(4-methoxyphenyl)sulfonyl]amino}-3-methylbutanoate

Participants

Reaction Steps

To a stirred suspension of 2-Amino-3-methyl-butyric acid tert-butyl ester (H-D-Val-OtBu.HCl) (500 mg, 2.38 mmol) in acetonitrile (20 ml) was added pyridine (767 μl, 9.52 mmol) at ambient temperature. A clear and colourless solution was quickly obtained. Then a solution of 4-methoxyl-benzenesulfonyl chloride (541 mg, 2.62 mmol) in acetonitrile (10 ml) was added dropwise and the mixture became slightly yellow coloured and was stirred at ambient temperature. TLC (EtOAc/Hexane, 1:1) monitoring showed the reaction was completed after 3 hours. After evaporation of acetonitrile, the residue was taken up in dichloromethane (30 ml) and extracted once each with 10% sodium bicarbonate solution (30 ml) and water (30 ml). Then the phases were separated and the dichloromethane phase was dried (Na2SO4), filtered and evaporated to afford the crude product. Flash chromatography using (Ethyl acetate/Hexane, 1:1) gave the pure product as a white solid. Yield 801 mg (93.90%).

Provenance & Evidence