To a 100 mL three-necked flask equipped with a thermometer, mechanical stirrer and reflux condenser were added 1,1-cyclohexanediacetic acid (10.0 g, 50 mmol) and formamide (4.5 g, 100 mmol). The reaction mixture was heated and the initial suspension was gradually transformed into a clarified colorless solution, the heating was continued and the reaction was stirred at 150-160 °C for 4 hours. The hot clarified reaction mixture was carefully poured into water (40 mL). The resulting colorless precipitate was collected, washed with water (10 mL) and subsequently dried under vacuum to afford 8.80 g (97% yield) of 3,3-cyclopentanediyl glutarimide as a colorless solid (99.9% purity by HPLC) with a melting point of 168-169 °C (literature value 169-170 °C).1H NMR (300 MHz, DMSO-d6) δ: 10.67 (broad peak, 1H), 2.42 (single peak, 4H), 1.30-1.41 (multiple peaks, 10H); 13C NMR (75 MHz, DMSO-d6) δ: 172.72, 42.50, 35.29, 32.45, 25.36, 20.97. Mass spectrometry (ESI-MS): calculated value (M+H)+ for C10H15NO2: 182.23, measured value: 182.21.
