Acetic Anhydride → HCID 86601468, compound

Participants

Reaction Steps

methyl 2-(tertbutoxycarbonyl)-3-hydroxypropanoate (29) (2.2 g, 10.0 mmol, 1.0 equiv.) was added to a 100 mL RBF followed by CH2Cl2 (40 mL). Next, DIEA (2.1 mL, 12.0 mmol, 1.2 equiv.) and acetic anhydride (1.2 mL, 13.0 mmol, 1.3 equiv.) were added to the reaction mixture and the solution was stirred at rt. The reaction solution was stirred for a total of 21 h. The solution was transferred to a separatory funnel with CH2Cl2 (75 mL), washed with 1% HCl (2×50 mL), and sat. NaCl (2×50 mL). The organic layers were dried over Na2SO4, concentrated on a rotary evaporator, and dried under vacuum to give 2.4 g (91%) of 30 as a clear oil which crystallized to a white solid upon standing. Rf=0.37 (25% EtOAc/hexanes); mp=61-62° C.; IR (KBr) 3327, 2985, 1742, 1683, 1533, 1348, 1241, 1166, 1071, 1038 cm−1; 1H NMR (500 MHz, CDCl3) δ 5.33 (br d, J=8.0 Hz, 1H, carbamate-NH), 4.58 (m, 1H, Boc-NH—CH), 4.44 (dd, J=11.0, 3.5 Hz, 1H, CH—CH2), 4.33 (dd, J=11.0, 3.5 Hz, 1H, CH—CH2), 3.78 (s, 3H, OCH3), 2.06 (s, 3H, O═C—CH3), 1.46 (s, 9H, t-butyl-CH3).; 13C NMR (125 MHz, CDCl3) δ 170.6, 170.5, 155.3, 80.5, 64.5, 53.0, 52.9, 28.4, 20.8; LRMS (ESI-MS m/z): Mass calcd for C11H19NNaO6 [M+Na]+, 284.26. Found 284.

Provenance & Evidence