Water → (S)-N-[2-(1,3-dihydro-1,3-dioxo-2H-isoindol-2-yl)-1-oxo-3-phenylpropyl]-1,4-dihydro-pyridine

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Reaction Steps

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 Na2SO4, 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.

Provenance & Evidence