49805-30-3

542-92-7

506-77-4

49805-30-3

In a 1000 mL reaction flask equipped with a thermometer and an off-gas absorption device, 500 mL of methanol, 50 g of cross-linked polystyrene-sulfinyl and 5.0 g of cyclopentadiene were added. The reaction system was cooled to 0-5°C and 2.5 g of cyanogen chloride gas was slowly passed through, while an ethanol solution of 5% sodium hydroxide was added dropwise to maintain the pH of the reaction system between 4-5. After the dropwise addition, the reaction was continued for 8 hours. After completion of the reaction, the solid was separated by filtration. The resulting solid was added to 100 mL of 5% ethanol solution of acetic acid and the reaction was continued for 8 hours at room temperature. Subsequently, the solid catalyst particles were removed by filtration and the filtrate was concentrated to afford the white crystalline product 2-azabicyclo[2.2.1]hept-5-en-3-one in a yield of 4.21 g in 95% yield (as cyanogen chloride) and 99.5% purity.