HCID 54174593, compound → HCID 18654575, compound

Participants

Reaction Steps

A solution of (S)-alpha-amino-N-[[(1,1 -dimethyethyl)oxy]carbonyl]-4-[[2-(cyclohexyloxy) ethyl]oxy]benzeneacetic acid benzyl ester (2.15 g) in dichloromethane (15 mL) containing trifluoroacetic acid (15 mL) was stirred at room temperature for 1 hour. After the solvents were removed under reduced pressure, the residue was dissolved in ethyl acetate and the mixture was basified to ~pH 9.5 with concentrated ammonium hydroxide. The organic layer was washed in turn with ammonium bicarbonate solution and brine, then was dried over anhydrous potassium carbonate (K2CO3) and evaporated to give 1.3 g of (S)-alpha-amino-4-[[2-(cyclohexyloxy)ethyl]oxy]benzeneacetic acid benzyl ester. A solution of the crude ester (1.25 g) in methanol (50 mL) was hydrogenated over 10% Pd/C at ambient temperature and pressure until the uptake of hydrogen had ceased. The reaction was diluted with methanol (100 ml), heated to reflux for five minutes, then the catalyst was filtered off through a bed of Celite, and washed with hot methanol (3×30 mL). The combined filtrates were concentrated at reflux to ~50 mL, then were cooled and the solids collected by filtration to yield 0.65 g of (S)-alpha-amino-4-[[2(cyclohexyloxy)ethyl]oxy]benzeneacetic acid, mp 219°-220° C.

Provenance & Evidence