(Boc-aminooxy)acetic acid is prepared by the reaction of Di-tert-butyl dicarbonate and Aminooxyacetic acid. The specific synthesis steps are as follows:
A 500 mL round-bottom flask was charged with a suspension of aminooxyacetic acid (4 g, 36.6 mmol) in CH2Cl2 (100 mL).
The solution was cooled to 0° C. and triethylamine (16 mL, 114 mmol) was added dropwise while stiffing to dissolve all solids.
To this mixture was added a solution of di-tert-butyl dicarbonate (12 g, 55 mmol) in CH2Cl2 (20 mL).
The reaction was stirred for 30 min at 0° C., then continued for 1 h at rt.
The solution was washed with three 100 mL portions of water.
The aqueous portion was combined and extracted with two 100 mL portions of EtOAc; this EtOAc was discarded.
The pH of the aqueous portion was adjusted to 3.5 with 1 M HCl, then extracted with five 50 mL portions of EtOAc, adjusting to maintain pH 3.5 as needed.
The combined EtOAc was dried over Na2SO4, filtered, and the solvent removed in vacuo to afford a white crystalline powder (5.8 g, 83percent). TLC: (MeOH:CH2Cl2, 1:9) Rf=0.08. 1H NMR (400 MHz, CD3OD): δ 1.48 (s, 9H), 4.47 (s, 2H), 7.94 (s, 1H).
13C NMR (100 MHz, CD OD): δ, 27.1, 47.0, 72.3, 81.4, 157.8, 171.3.
