Cyclooctanone → N-cyclooctyl-gamma-tert-butyl-L-glutamic acid

関与物質

反応手順

To a stirred suspension of γ-tert-butyl-L-glutamic acid (4.06 g, 20.0 mmol) and cyclooctanone (3.15 g, 25 mmol) in N,N-dimethylformamide/acetic acid (99:1, v/v, 50 mL) was added sodium triacetoxyborohydride (6.36 g, 30.0 mmol) in small portions and the mixture was stirred overnight. After evaporation of the solvent, the residue was dissolved in water (50 mL). The pH was adjusted to 9 with 2 N sodium hydroxide solution, followed by extraction with diethylether (50 mL). Subsequently, the pH of the aqueous layer was carefully adjusted to 2.5 using 1.0 N hydrochloric acid. Extraction with dichloromethane afforded an organic layer, which was dried (magnesium sulphate) and concentrated under reduced pressure, yielding 4.82 g (77%) of the title compound as a white solid. ESI-MS: 314.2 (M+H)+, 336.2 (M+Na)+. Rf (silica gel; ethyl acetate/pyridine/acetic acid/water 63:20:6:11, v/v): 0.80.

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