Sodium Hydroxide → 2-[(Dimethylamino)methylidene]cyclohexane-1,3-dione

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Reaction Steps

To an ethanol suspension (60 ml) of 10.73 g (40 mmol) of 1-amidino-4-benzylpiperazine sulfate, were added an ethanol solution (80 ml) of 1.6 g (40 mmol) of sodium hydroxide and then 6.69 g (40 mmol) of the 2-dimethylaminomethylenecyclohexane-1,3-dione obtained in Referential Example 46. The resultant mixture was heated under reflux for 4 hours. After cooling the reaction mixture to room temperature, the solvent was distilled off. The residue was added with 100 ml of water and then extracted twice with 200 ml of ethyl acetate. The ethyl acetate layer was washed with saturated saline and then dried with anhydrous magnesium sulfate. Ethyl acetate was the distilled off under reduced pressure. The residue was purified by silica gel column chromatography (eluent: ethyl acetate/hexane=3/7) to obtain 9.90 g of the intended product as light yellowish crystals (yield: 77%).

Provenance & Evidence