反应详情

To a solution of benzimidic acid methyl ester hydrochloride (1 g) in MeOH (25 ml) was added 1,2-diaminopropane (545 μL) then the mixture was heated to reflux. After 16 h the mixture was cooled to room temperature and concentrated. The residue was taken up in MeOH then passed through Dowex 1×2-400 ion exchange resin (prewashed with 1M NaOH, H2O, MeOH) washing with MeOH. The filtrate was concentrated. Flash column chromatography (gradient, 0-10% MeOH/CHCl3 saturated with NH3) gave 4-methyl-2-phenyl-4,5-dihydro-1H-imidazole as a white solid (1.04 g) which was sufficiently pure for use in the next step. 1H-NMR (400 MHz, CDCl3) δ 7.84 (m, 2 H), 7.55-7.38 (m, 3 H), 4.16 (m, 1 H), 3.95 (dd, J=9.98 and 1.83 Hz, 1 H), 3.40 (m, 1 H), 1.32 (d, J=6.41 Hz, 3 H).

1. temperaturethe mixture was heated to reflux
2. concentrationconcentrated
3. washwashing with MeOH
4. concentrationThe filtrate was concentrated