Ethyl bromoacetate → (4-Methylpiperazin-1-yl)acetic acid

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Reaction Steps

Dissolve N-methylpiperazine (5.0 mL, 45.09 mmol) in diethyl ether in a stoppered flask and treat with neat ethyl bromoacetate (3.012 g, 18.036 mmol). Stir the reaction mixture at room temperature overnight, filter and wash the filter cake with diethyl ether. Combine the organic filtrates and evaporate the solvent in vacuo to give a light yellow oil. Take up in water (60 mL) and heat at 95° C. for 4 hours, allow to cool to room temperature and stir overnight. Evaporate the solvent in vacuo and dissolve the residue in acetonitrile and evaporate the solvent in vacuo (twice) to azeotrope residual water. Dissolve in a minimal amount of methanol, dilute with diethyl ether and place in the freezer. Isolate the crystals which form by decanting the supernatant and wash with diethyl ether. Obtain two more crops of crystals from the mother liquor to give 4-methylpiperazine-1-acetic acid (2.345 g, 82%); mp 158°-160° C. (lit 159.5°-161° C.), 1H NMR (D2O) δ3.98 (s, 2), 3.81-3.32 (m, 8), 2.89 (s, 3).

Provenance & Evidence