反应详情

温度

-10 °C

Methyl 1-methyl-2-oxo-4-imidazolidinecarboxylate (1 g, 6.32 mmol) (prepared as described in step (iii) of Example 1, starting from (4S)-2-oxo-3-{[(phenylmethyl)oxy]carbonyl}-4-imidazolidinecarboxylic acid) was dissolved in anhydrous tetrahydrofuran (10 ml), cooled to −10° C. under argon, and treated with methyl iodide (1.57 ml, 25.3 mmol). Sodium hydride (60% in oil, 0.24 g, 6.0 mmol) was then added in portions over a period of 15 minutes and the mixture was allowed to warm to room temperature and stirred for 18 hrs. The reaction mixture was then reduced in vacuo and the residue partitioned between ethyl acetate (40 ml) and brine (20 ml). The organic layer was separated, passed through a hydrophobic frit, and reduced in vacuo to give a yellow oil. This material was purified by automated flash silica gel column chromatography (Biotage SP4), eluting with 50% ethyl acetate in hexane (5 column volumes) and then with a gradient of 50-80% in hexane (15 column volumes), to give methyl 1,3-dimethyl-2-oxo-4-imidazolidinecarboxylate (0.479 g) as a yellow oil which was used without further purification.

1. temperatureto warm to room temperature
2. customthe residue partitioned between ethyl acetate (40 ml) and brine (20 ml)
3. customThe organic layer was separated
4. customto give a yellow oil
5. customThis material was purified by automated flash silica gel column chromatography (Biotage SP4)
6. washeluting with 50% ethyl acetate in hexane (5 column volumes)