2-[2-(2-Oxo-1-piperidinyl)ethyl]-1H-isoindole-1,3(2H)-dione

2-[2-(2-Oxo-1-piperidinyl)ethyl]-1H-isoindole-1,3(2H)-dione

Pthalimide (952 mg, 6.47 mmol) was added to a solution of the product from preparation 5 (842 mg, 5.88 mmol) in tetrahydrofuran (30 ml), and the mixture sonicated until a solution was obtained. Polymer supported triphenyl phosphine (2.5 g, 7.5 mmol) and diethyl azodicarboxylate (1.15 ml, 7.31 mmol) were added, and the reaction stirred at room temperature for 18 hours. The mixture was filtered through Arbocel®, the filtrate concentrated under reduced pressure and the residue azeotroped with dichloromethane. The crude product was purified by column chromatography on silica gel using an elution gradient of ethyl acetate:pentane (70:30 to 100:0), to give the title compound as a white foam, 1.6 g (containing some impurities); 

¹H NMR (CDCl₃, 400 MHz) δ: 1.60-1.80 (m, 4H), 2.17 (m, 2H), 3.30 (m, 2H), 3.60 (m, 2H), 3.83 (m, 2H), 7.62 (m, 2H), 7.79 (m, 2H); LRMS: m/z 273.2 (MH⁺).