BOC-D-ALA-NH2

General procedure: To a stirred solution of N-Boc-(R)-alanine (5.0 g, 26.4 mmol) in dry THF at -10 °C, were added triethylamine (3 mL, 21.12 mmol) and ethyl chloroformate (2.5 mL, 26.4 mmol). The reaction mixture was stirred for 1 h and then NHStep 1: tert-Butyl[(1S)-2-amino-1-methyl-2-oxoethyl]carbamate To a stirred solution of (2S)-2-[(tert-butoxycarbonyl)amino]propanoic acid (1 g, 0.005 mol) in THF at 0° C. was added 4-methylmorpholine (0.588 g, 0.00581 mol) followed by dropwise addition of isobutyl chloroformate (0.794 g, 0.00581 mol) over 2 min. The reaction was stirred at 0° C. for 30 min. after which a solution of 30 wt. percent ammonium hydroxide (12.0 mL, 0.0925 mol) was quickly poured into the reaction. The reaction was warmed to room temperature and stirred for 5 h. The reaction mixture was concentrated. Water was added and the mixture extracted with ethyl acetate. The combined organic layers were washed with brine, dried over MgSOTo a solution containing Boc-L-alanine (1.0 g, 5.29 mmol) in a mixture of tetrahydrofuran (25 mL) and N, N-dimethylformamide (5 mL) were added EDAC (1.5 g, 7.82 mmol) and N-hydroxysuccinimide (0.91 g, 7.91 mmol) and the mixture was stirred at room temperature for 16 hours. Aqueous ammonium hydroxide solution (15 mL, 28percent) was added and the mixture was stirred for 0.5 hours at room temperature. The reaction was partitioned between ethyl acetate and water, and the organic was washed with brine and dried over MgSOExample 474Atert-butyl (1S)-2-amino-1-methyl-2-oxoethylcarbamateTo a solution containing Boc-L-alanine (1.0 g, 5.29 mmol) in a mixture of tetrahydrofuran (25 mL) and N, N-dimethylformamide (5 mL) were added EDAC (1.5 g, 7.82 mmol) and N-hydroxysuccinimide (0.91 g, 7.91 mmol) and the mixture was stirred at room temperature for 16 hours. Aqueous ammonium hydroxide solution (15 mL, 28percent) was added and the mixture was stirred for 0.5 hours at room temperature. The reaction was partitioned between ethyl acetate and water, and the organic was washed with brine and dried over MgSOEthyichioroformate (3.4 g, 31.3 mmol) and Et3N (7.0 mL, 52.8 mmol) were added to a solution of compound la (5.0 g, 26.4 mmol) in THF (20 mL) and stirred at - 20 °C for 20 mm. After 20 minutes 25percent of aqueous ammonia (10 mL, 132.0 mmol) was added to the active mixed anhydride and stirred at 0-5 °C for 30 mm. The completeness of the reaction was confirmed by TLC analysis. The volatiles were evaporated underreduced pressure and partitioned between water and ethyl acetate. The organic layer was washed with NaHCO3 solution followed by citric acid solution and brine solution. The separated organic layer was dried over Na2SO4, filtered and evaporated under reduced pressure to yield 4.0 g of compound lb. LCMS: 89.3 (M-Boc+H).A mixture of Boc-Ala-OMe (5.000 g, 24.6 mmol, 1.0 equiv.) and 28percent aqueous ammonium hydroxide (100.00 mL, 1479.7 mmol, 60.1 equiv.) in methanol (100 mL) was stirred for 16 h at room temperature. The reaction mixture was concentrated in vacuo to afford the desired product as a white solid (4.65 g, 100percent).