Allylamine → HCID 10012544, compound

Participants

Reaction Steps

A solution of 3,4-diethoxy-3-cyclobutene-1,2-dione (5.2 g, 31 mmol) in ethanol (80 mL) was treated at room temperature with allylamine (2.3 mL, 31 mmol), which was dissolved in ethanol (40 mL), over a 2 hour period. The reaction mixture was concentrated in vacuo to afford crude 1-(2-propenylamino)-2-ethoxy-3,4-dioxo-1-cyclobutene as a light yellow solid (5.6 g). The crude intermediate was dissolved in anhydrous dimethylformamide (50 mL) and added dropwise to a suspension of 60% sodium hydride (1.5 g, 37 mmol) in anhydrous dimethylformamide (50 mL) under nitrogen. The anion was quenched with t-butyl bromoacetate (6.0 mL, 37 mmol) and the reaction mixture was stirred for 1.5 hours, poured into water (500 mL), extracted with ethyl acetate (2×200 mL), and dried (MgSO4) to yield N-(2-ethoxy-3,4-dioxo-1-cyclobuten-1-yl)-N-(2-propenyl)glycine 1,1-dimethylethyl ester. Purification was achieved by flash chromatography (10 cm diameter, elution with 20% ethyl acetate in petroleum ether) affording a yellow oil (4.56 g, 50%); 1H NMR (CDCl3, 300 MHz): δ 5.88-5.72 (m, 1H), 5.35-5.22 (m, 2H), 4.80-4.68 (m, 2H), 4.35, 4.08 (d, J=7 Hz, 2H), 4.28, 3.95 (s, 2H), 1.48 (s, 9H), 1.45 (t, J=7 Hz, 3H).

Provenance & Evidence