反应详情

Combine phthalimido-(S)-phenyalanine amide (3.0 g, 10 mmol) and a solution of glutaric dialdehyde (2.0 g; 50% by weight in water) in dichloromethane (200 mL). Heat to reflux with azeotropic removal of water from the refluxate. Add p-toluenesulfonic acid (60 mg). Continue heating at reflux. Pass the refluxate through oven dried 4 Å molecular sieves. After 4 days, cool the reaction mixture to ambient temperature. Extract with 5% sodium bicarbonate solution. Extract the 5% sodium bicarbonate solution with dichloromethane. Combine the organic layers and dry over Na2 SO4, filter, and evaporate in vacuo to give a residue. Chromatograph the residue on silica gel eluting with 5% tetrahydrofuran/dichloromethane to give the title compound.

1. temperatureHeat
2. temperatureContinue heating
3. temperatureat reflux
4. customPass the refluxate through oven dried 4 Å molecular sieves
5. extractionExtract with 5% sodium bicarbonate solution
6. extractionExtract the 5% sodium bicarbonate solution with dichloromethane
7. customdry over Na2 SO4
8. filtrationfilter
9. customevaporate in vacuo
10. customto give a residue