反应详情

A mixture of the dihydro-imidazole of step 3 (3. 95 g, 13.9 mmol) and p-toluenesulfonic acid monohydrate (785 mg, 4 mmol) in toluene (500 ml) was heated to reflux for 4–5 hours. The reaction mixture was cooled and 10 ml of triethylamine was added and the solvent removed-under reduced pressure. The crude mixture was purified by chromatography on silica gel using ethyl acetate to give the desired product which was used in the next reaction without further purification.

1. temperaturewas heated
2. temperatureto reflux for 4–5 hours
3. temperatureThe reaction mixture was cooled
4. customThe crude mixture was purified by chromatography on silica gel