Toluene → Ethyl 1-benzyl-4-oxo-2-imidazolidinepropanoate

Participants

Reaction Steps

A suspension of N-benzylglycinamide (35.5 g, 0.22 mol) and ethyl 4-oxobutanoate (31 g, 0.24 mol) in toluene (370 ml) was refluxed for 6 hours in a Dean-Stark apparatus. After cooling, the mixture was extracted twice with 10% sulphuric acid (200+100 ml); the aqueous extracts were neutralized with sodium hydrogen carbonate and extracted twice with toluene (250 ml of each time). The organic solution was washed with water (100 ml), dried (MgSO4) and evaporated under vacuum to afford an oil which was triturated with a mixture of diethyl ether-light petroleum (1:2) to give 45 g (75%), of the title compound as a yellow solid, m.p. 60°-62° C. NMR (CDCl3): deltaH =7.5 (bs, 1H, NH); 7.30 (bs, 5H, PhH); 4.5-4.25 (ABX, 1H, CH--M); 4.13 (q, J=6.9 Hz, 2H, OCH2); 4.00 and 3.53 (ABq, J= 12.4 Hz, 2H, PhCH2); 3.37 and 3.02 (ABX, J=14.9 Hz, 2H, NCH2CO); 2.65-2.30 (c.a., 2H, CH2CH2CO); 2.20-1.15 (c.a., 2H, CH2CH2CO); 1.24 (t, J=6.9 Hz, 3H, CH3). MS (E.I., 70 eV, 1.5 mA) m/z=276 (M+), 231 (M--OEt)+, 185 (M--PhCH2)+, 175 (M--C5H9O2)+, 91 (PhCH2)+.

Provenance & Evidence