Sodium Hydroxide → isobutyl (4S)-4-benzyl-5-oxo-2-imidazolidinepropanoate

Participants

Reaction Steps

To a solution of L-phenylalaninamide hydrochloride (20 g, 0.1 mol) in water (200 ml), adjusted to pH 8.2 with 10% sodium hydroxide (about 35 ml), was added isobutyl 4-oxobutanoate (16 g, 0.1 mol). The solution was refluxed for 24 hours After cooling, the solution was extracted with dichloromethane (4×200 ml). The organic phase was dried and evaporated to dryness under vacuum. The residue was chromatographed over silica gel (dichloromethanemethanol 9:1) to afford 6 g (20%) of the title compound, as an oil, which was characterized as the hydrochloride, m.p. 152°-155° C. (with decomposition) (after crystallization from ethanol-diethyl ether). NMR (DMSO-d6, CDCl13): deltaH =9.25 (b.s., 1H, CONH); 7.6-7.1 (c.a., 5H, PhH), 4.90 (t, J=6.1 Hz, 1H, NHCHNH); 4.17 (t, J=6.1 Hz, 1H, CHCH2Ph); 3.84 (d, J=6.9 Hz, 2H, COOCH2CH); 3.35 (c.a., 2H, CH2Ph); 2.50-1.60 (c.a., 5H, CH2CH2COO, CH2CH(CH3)2. MS (E.I., 70 eV, 1.5 mA) m/z=304 (M+), 213 (M--C7H7)+, 84 (C3H4N2O)+.

Provenance & Evidence