Acetic Acid → HCID 54227914, compound

Participants

Reaction Conditions

Reaction Steps

Under an argon gas stream, N-(tert-butoxycarbonyl)-L-norleucine methyl ester (10.7 g, 38 mmol) was dissolved in toluene (68 ml), and cooled to -78° C. To the solution, while keeping the temperature at -60 to -70° C., was added gradually aluminum diisobutyl hydride (toluene 1.0 M solution, 51 ml). After stirring at -78° C. for an hour, the cooling bath was removed, methanol (2 ml) was added to the mixture. Tyrosine methyl ester hydrochloride (13.6 g, 59 mmol) and acetic acid (3.5 g, 59 mmol) were dissolved in methanol (69 ml)-tetrahydrofuran (98 ml), and added to the mixture. After addition of a suspension of sodium cyanoborohydride (2.7 g, 43 mmol) in tetrahydrofuran (30 ml), the mixture was stirred at room temperature for 2.5 hours, and water was added thereto. The solid was removed by decantation, and the solution was concentrated under reduced pressure. The organic matters were extracted with ethyl acetate, and washed with a saturated aqueous sodium bicarbonate solution, water and a saturated aqueous sodium chloride solution, successively. The organic layer was concentrated under reduced pressure and purified by column chromatography to give N-[(S)-2-(tert-butoxycarbonylamino)hexyl]-L-tyrosine methyl ester (4.9 g).

Provenance & Evidence