Diethyl (ethoxymethylene)malonate → 1-Cyclohexylmethyl-2-oxo-1,2,5,6,7,8,9,10-octahydro-cycloocta[b]pyridine-3-carboxylic acid

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Reaction Steps

Under the nitrogen gas atmosphere, a solution of cyclooctanone (15 g, 118 mmol) and cyclohexylmethylamine (16.1 g, 142 mmol) in toluene (300 mL) was refluxed under azeotropic dehydration for 6 hours. After that, diethyl ethoxymethylenemalonate (24 mL, 142 mmol) was added, and the mixture was further refluxed for 2 hours. After the reaction mixture had been removed by distillation under reduced pressure, the residue was dissolved in the mixed solvent of THF (200 mL) and methanol (200 mL), then a 2M sodium hydroxide aqueous solution was added and the mixture was stirred for 2 hours at room temperature. The reaction mixture was removed by distillation under reduced pressure, water was added to the residue and the water layer was washed with diethyl ether one time. Then, after 2 M hydrochloric acid was added to the water layer to acidify it, the water layer was extracted with ethyl acetate. The organic layer was washed with water and then dried with anhydrous sodium sulfate. The solvent was removed by distillation under reduced pressure and a pale yellow solid (AA01, 21.5 g, 57%, mp: 162-163° C.) was obtained

Provenance & Evidence