2-[(2-methylpropan-2-yl)oxycarbonyl-propan-2-ylamino]acetic acid

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Subsequently, to a solution of (N-t-butoxycarbonyl-N-isopropyl-amino)-acetic acid (2.05 g, 9.44 mmol) and p-nitrobenzyl alcohol (2.89 g, 18.9 mmol) in methylene chloride (100 ml) were added WSC (3.62 g, 18.9 mmol) and 4-dimethylaminopyridine (120 mg, 0.98 mmol) in an ice bath under an atmosphere of nitrogen, and then the mixture was stirred at room temperature overnight. After checking the completion of the reaction, the reaction mixture was partitioned between ethyl acetate and saturated aqueous sodium chloride solution. The organic layer was dried over anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. The residue was purified by chromatography on a silica gel column using hexane:ethyl acetate (5:2) as the eluant to afford (N-t-butoxycarbonyl-N-isopropyl-amino)acetic acid p-nitrobenzyl ester (1.93 g, yield 58%) as a pale yellow transparent syrup. the completion of the reaction the reaction mixture was partitioned between ethyl acetate and saturated aqueous sodium chloride solution The organic layer was dried over anhydrous magnesium sulfate filtered concentrated under reduced pressure The residue was purified by chromatography on a silica gel column

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Subsequently, to a solution of (N-t-butoxycarbonyl-N-isopropyl-amino)-acetic acid (2.05 g, 9.44 mmol) and p-nitrobenzyl alcohol (2.89 g, 18.9 mmol) in methylene chloride (100 ml) were added WSC (3.62 g, 18.9 mmol) and 4-dimethylaminopyridine (120 mg, 0.98 mmol) in an ice bath under an atmosphere of nitrogen, and then the mixture was stirred at room temperature overnight. After checking the completion of the reaction, the reaction mixture was partitioned between ethyl acetate and saturated aqueous sodium chloride solution. The organic layer was dried over anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. The residue was purified by chromatography on a silica gel column using hexane:ethyl acetate (5:2) as the eluant to afford (N-t-butoxycarbonyl-N-isopropyl-amino)acetic acid p-nitrobenzyl ester (1.93 g, yield 58%) as a pale yellow transparent syrup. the completion of the reaction the reaction mixture was partitioned between ethyl acetate and saturated aqueous sodium chloride solution The organic layer was dried over anhydrous magnesium sulfate filtered concentrated under reduced pressure The residue was purified by chromatography on a silica gel column

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of (N-t-butoxycarbonyl-N-isopropyl-amino)-acetic acid methyl ester (5.59 g, 24.2 mmol) in a mixture of methanol (112 ml) and distilled water (56 ml) was added 1M aqueous sodium hydroxide solution (37 ml) in an ice bath, and the mixture was stirred at room temperature for 7 hours. After checking the completion of the reaction, Dowex-50W was added thereto in the ice bath to adjust the pH of the reaction mixture to 5 to 4. The reaction mixture was filtered and the filtrate concentrated under reduced pressure to give (N-t-butoxycarbonyl-N-isopropyl-amino)acetic acid (5.25 g) as a crude product. distilled water (56 ml) was added 1M aqueous sodium hydroxide solution (37 ml) in an ice bath the completion of the reaction, Dowex-50W was added The reaction mixture was filtered the filtrate concentrated under reduced pressure

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Subsequently, to a solution of (N-t-butoxycarbonyl-N-isopropyl-amino)-acetic acid (2.05 g, 9.44 mmol) and p-nitrobenzyl alcohol (2.89 g, 18.9 mmol) in methylene chloride (100 ml) were added WSC (3.62 g, 18.9 mmol) and 4-dimethylaminopyridine (120 mg, 0.98 mmol) in an ice bath under an atmosphere of nitrogen, and then the mixture was stirred at room temperature overnight. After checking the completion of the reaction, the reaction mixture was partitioned between ethyl acetate and saturated aqueous sodium chloride solution. The organic layer was dried over anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. The residue was purified by chromatography on a silica gel column using hexane:ethyl acetate (5:2) as the eluant to afford (N-t-butoxycarbonyl-N-isopropyl-amino)acetic acid p-nitrobenzyl ester (1.93 g, yield 58%) as a pale yellow transparent syrup. the completion of the reaction the reaction mixture was partitioned between ethyl acetate and saturated aqueous sodium chloride solution The organic layer was dried over anhydrous magnesium sulfate filtered concentrated under reduced pressure The residue was purified by chromatography on a silica gel column

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of (N-t-butoxycarbonyl-N-isopropyl-amino)-acetic acid methyl ester (5.59 g, 24.2 mmol) in a mixture of methanol (112 ml) and distilled water (56 ml) was added 1M aqueous sodium hydroxide solution (37 ml) in an ice bath, and the mixture was stirred at room temperature for 7 hours. After checking the completion of the reaction, Dowex-50W was added thereto in the ice bath to adjust the pH of the reaction mixture to 5 to 4. The reaction mixture was filtered and the filtrate concentrated under reduced pressure to give (N-t-butoxycarbonyl-N-isopropyl-amino)acetic acid (5.25 g) as a crude product. distilled water (56 ml) was added 1M aqueous sodium hydroxide solution (37 ml) in an ice bath the completion of the reaction, Dowex-50W was added The reaction mixture was filtered the filtrate concentrated under reduced pressure