(3-Bromopropyl)benzene → (R)-Methyl 2-amino-3-(benzyloxy)propanoate

Participants

Reaction Steps

A solution of sodium ethoxide was generated by the addition of sodium metal (52.89 grams, 2.3007 mol) over 3 hours to ethanol (1500 mL). To the sodium ethoxide solution at ambient temperature was added a solution of diethylacetamidomalonate (499.75 grams, 2.3007 mol) dissolved in ethanol (225 mL). The reaction mixture was stirred for 1.5 hours at ambient temperature. 1-bromo-3-phenylpropane (458.07 grams, 2.3007 mol) was added over 15 minutes and the reaction mixture was refluxed until complete as determined by hplc (16 hours). The reaction mixture was concentrated to dryness and the residue partitioned between ethyl acetate (1×1500 mL and 2×500 mL) and water (1500 mL). The ethyl acetate layers were combined, washed with saturated sodium chloride solution (4×500 mL), dried using sodium sulfate, and concentrated to give 752.1 grams (98%) of the desired compound as a light yellow solid. A 1.0 gram sample was recrystallized from hexane:ethyl acetate (19:1, v:v) to give a mp 84-86° C. 1H nmr (CDCl3): δ1.18-1.23 (t, 6H), 1.37-1.50 (m, 2H), 2.02 (s, 3H), 2.34-2.41 (m, 2H), 2.58-2.62 (t, 2H), 4.16-4.24 (q, 4H), 6.76 (s, broad, 1H), 7.11-7.28 (m, 5H). 13C nmr (CDCl3): δ13.95, 23.03, 25.67, 31.85, 35.45, 62.46, 66.49, 125.40, 125.90, 128.27, 128.35, 141.77, 168.11, 168.94. MS (FIA) m/z 336.3 ([M+H]+). IR (KBr, cm−1) 1645.98 (amide), 1744.76 (C=O). Anal. Calcd. for C18H25NO5: C, 64.46; H, 7.51; N, 4.17. Found: C, 64.60; H, 7.37; N, 4.39.

Provenance & Evidence