The general procedure for the synthesis of 1-(4-pyridyl)-piperidin-4-one from the compound (CAS:166954-75-2) was as follows: 79.7 g of the aforementioned ketone was dissolved in 2 L of tetrahydrofuran, followed by the addition of 1000 mL of 6 N hydrochloric acid solution. The reaction mixture was stirred at room temperature for 2 hours. Upon completion of the reaction, the solvent was removed by evaporation and concentration, and the pH was adjusted to alkaline with semi-concentrated ammonia. Extraction was carried out using dichloromethane and the combined organic phases were concentrated by evaporation to give 64.2 g (quantitative yield) of 2,3,5,6-tetrahydro-[1,4']bipyridin-4-one, which has a melting point of 102 °C.
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![8-(pyridin-4-yl)-1,4-dioxa-8-azaspiro[4.5]decane](/CAS/20180703/GIF/166954-75-2.gif)