Lithium Hydroxide → (R)-2-Acetamido-3-(prop-2-ynyloxy)propanoic Acid

Participants

Reaction Conditions

Reaction Steps

(R)-Methyl 2-acetamido-3-(prop-2-ynyloxy)propanoate (1.00 g, 5.03 mmol) was dissolved in THF (24 mL) and cooled to 0° C., and LiOH (aqueous 0.6 M sol., 8.4 mL, 5.03 mmol) was added. The reaction solution was stirred at 0° C. (2 h) and then concentrated in vacuo. The resulting aqueous phase was diluted with H2O (12 mL) and washed with Et2O (2×20 mL). The aqueous layer was acidified to pH 1-2 with aqueous 1 M HCl, and extracted with EtOAc (6×20 mL). The combined organic phases were washed with saturated aqueous brine (80 mL), dried (Na2SO4) and evaporated in vacuo to yield 0.87 g of desired product (94%) as a yellow oil: Rf=0.35 (15/5/1 EtOAc/hexanes/AcOH); IR (nujol mull) 2924, 2120, 1726, 1642, 1548, 1459 cm−1; 1H NMR (CD3OD) δ 2.01 (s, CH3C(O)), 2.88 (t, J=2.6 Hz, CH2CCH), 3.77 (dd, J=3.6, 9.7 Hz, CHH′OCH2), 3.92 (dd, J=5.0, 9.7 Hz, CHH′OCH2), 4.18 (d, J=2.6 Hz, OCH2C), 4.61-4.64 (m, CH); 13C NMR (CD3OD) δ 22.5 (CH3C(O)), 54.1 (CH), 59.3 (CH2CCH), 70.4 (CH2OCH2), 76.5 (CH2CCH), 80.2 (CH2CCH), 173.1, 173.5 (2 C(O)); HRMS (ESI) 186.0761 [M+H+] (calcd. for C8H12NO4 186.0766); Anal. (C8H11NO4, 0.14H2O) Calcd.: C, 51.18%; H, 6.06%; N, 7.46%. Found: C, 51.15%; H, 6.13%; N, 7.27%.

Provenance & Evidence