4-[(tert-Butoxycarbonyl)(methyl)amino]butanoic acid

24424-99-5

6976-17-6

94994-39-5

At room temperature, 4-(methylamino)butyric acid hydrochloride (1.00 g, 6.51 mmol) and triethylamine (2.72 mL, 19.5 mmol) were dissolved in dichloromethane (60 mL) and mixed with stirring. Subsequently, di-tert-butyl dicarbonate (1.56 g, 7.16 mmol) was slowly added to the mixture. The reaction mixture was stirred continuously at room temperature for about 72 hours. The reaction progression was monitored by LC-MS to confirm product formation (retention time 4.11 min; m/z 216.2 [M + H]+). Upon completion of the reaction, dichloromethane and water were added for dilution, and the pH of the aqueous layer was adjusted to 4.5-6.0 with 1 M aqueous hydrochloric acid.The organic and aqueous layers were separated, and the organic layer was dried over anhydrous sodium sulfate, filtered, and then concentrated under reduced pressure to afford 4-(tert-butoxycarbonyl(methyl)amino)butyric acid (1.5 g, 100% yield) as a light yellow thick oil.1H NMR (CDCl3) δ: 3.28 (broad peak, 1H), 2.85 (single peak, 3H), 2.35 (triple peak, 2H), 1.84 (triple peak, 2H), 1.46 (single peak, 9H).