Hydrochloric Acid → methyl (3S)-3-hydroxy-3-{6-[(methylamino)carbonyl]-2-naphthyl}-3-(1-trityl-1H-imidazol-4-yl)propanoate

Participants

Reaction Steps

Under argon atmosphere, 0.49 g (1.66 mmol, 1.25 equivalents) of (+)-cinchonine was added to 10 mL (5.4 mmol) of the solution of methyl bromozincacetate in tetrahydrofuran obtained in Example 55 at 5˜8° C. 0.43 mL (5.32 mmol, 4 equivalents) of pyridine was added dropwise at 6˜8° C. The mixture was stirred at 4˜6° C. for 20 minutes. A solution of 0.69 g (1.32 mmol) of N-methyl-6-[(1-trityl-1H-imidazol-4-yl)carbonyl]-2-naphthamide in 6.9 mL of THF was added dropwise at −35˜−40° C. The mixture was stirred at −40˜−35° C. for 1 hour. 2.5 mL (1.32 mmol) of the solution of methyl bromozincacetate in tetrahydrofuran obtained in Example 55 was added dropwise at −40° C., and the mixture was stirred at −40˜−35° C. for 1 hour. 20 mL of 1N hydrochloric acid was added dropwise at 0° C. or lower, followed by dilution with 30 mL of ethyl acetate. The layers were separated. The organic layer was washed successively with 5 mL of 1N hydrochloric acid, 5 mL of water, 5 mL (×2) of an aqueous saturated sodium bicarbonate solution, 5 mL of water, and 5 mL (×2) of an aqueous saturated sodium chloride solution. After washing and concentration under reduced pressure, 4 mL of IPE was added, crystals were loosened, filtered, and washed with 1 mL (×2) of IPE. After washing, vacuum drying (40° C.) to a constant weight afforded 0.72 g of methyl (3S)-3-hydroxy-3-{6-[(methylamino)carbonyl]-2-naphthyl}-3-(1-trityl-1H-imidazol-4-yl)propanoate (yield 92%, enantiomer excess 93.6% ee).

Provenance & Evidence