Triethylamine → 5-Chloro-N-{2-[1-(cyanomethyl)-4-piperidinyl]-1,3-dioxo-2,3-dihydro-1H-isoindol-4-yl}-2-thiophenecarboxamide

A mixture of 100 mg (0.26 mmol) of 5-chloro-N-[1,3-dioxo-2-(4-piperidinyl)-2,3-dihydro-1H-isoindol-4-yl]-2-thiophenecarboxamide, 0.022 ml (0.31 mmol) of α-bromoacetonitrile and 0.072 ml (0.51 mmol) of triethylamine in 2.5 ml of DMF are stirred at room temperature overnight. The mixture is concentrated and the residue is taken up in dichloromethane, washed with sodium bicarbonate solution, dried over magnesium sulfate and concentrated. The product is crystallized with ether, filtered off with suction and dried under high vacuum. Alternatively, the product can be purified by chromatography on silica gel (dichloromethane/methanol mixtures).