82683-51-0

933-02-8

105-53-3

82683-51-0

GENERAL STEPS: A mixture of 1-cyclopentadienylpropan-2-one (1 g, 9.4 mmol) and diethyl malonate (1.75 g, 11 mmol) was slowly added dropwise to a sodium methanolate solution prepared from sodium metal (0.25 g, 11 mmol) dissolved in methanol (3 mL). The reaction mixture was heated under reflux conditions for 2 hours. Subsequently, a hot solution of barium hydroxide (11.23 g, 73 mmol) dissolved in 100 mL of water was added to the reaction system and reflux was continued for 24 hours. After the reaction was completed, it was neutralized to pH 6 with dilute hydrochloric acid and filtered while hot. The filtrate was cooled, acidified to pH 1 with dilute hydrochloric acid, refluxed again for 15 min, filtered while hot and cooled. The precipitated solid was filtered, washed with water and dried to give 0.87 g (56% yield) of spiro[4.5]decane-7,9-dione.