反应详情

1-(5-carboxypentyl)-2,3,3-trimethylindolium bromide (1.77 g, 5 mmol) and N,N′-diphenylformamidine (1.96 g, 10 mmol) were mixed in acetic acid (15 m); the resulting mixture was then heated at reflux. The reaction was monitored by UV/VIS spectroscopy (methanol solution, product absorbance λmax 398 nm) and TLC (silica. Methanol, 20: dichloromethane, 80; product runs as a yellow streak, Rf 0.1-0.25). After 2.5 hrs the orange-red solution was then left to cool over 16 hrs, then the solvent was removed under reduced pressure. The residue was purified by flash chromatography (silica. 5-20% methanol/dichloromethane) to give the title compound [1.3] as a yellow-orange foam after drying, 1.5 g (66%).

1. temperaturethe resulting mixture was then heated
2. temperatureat reflux
3. temperatureto cool over 16 hrs
4. customthe solvent was removed under reduced pressure
5. customThe residue was purified by flash chromatography (silica. 5-20% methanol/dichloromethane)